Anisodine hydrobromide alleviates oxidative stress caused by hypoxia/reoxygenation in human cerebral microvascular endothelial cells predominantly via inhibition of muscarinic acetylcholine receptor 4

Background:Anisodine hydrobromide(AT3),an anti-cholinergic agent,could be delivered to the brain across the blood-brain barrier and has been used clinically for the treatment of cerebral ischemia/reperfusion injury.Endothelial dysfunction can be caused by hypoxia/reoxygenation(H/R)via oxidative stress and metabolic alterations.The present study investigated whether AT3 regulates the production of nitric oxide(NO)and reactive oxygen species(ROS),and the HIF-1αpathway via regulation of muscarinic acetylcholine receptors(mAChRs)in brain microvascular endothelial cells after H/R exposure.Methods:Under H/R conditions,hCMEC/D3 cerebral microvascular endothelial cells were treated with AT3.Specific inhibitors of M2-and M4-mAChRs were used to explore the mechanism by which AT3 influences oxidative stress in endothelial cells.Then,mAChRs expression was detected by western blotting and NO production was detected by Greiss reaction.The intracellular ROS level was measured using DCFH-DA probes.The expression of hypoxia-inducible transcription factor 1α(HIF-1α)was also detected.Results:While H/R induced the expression of M2-and M4-mAChRs,AT3 suppressed the H/R-upregulated M2-and M4-mAChRs.H/R also induced the production of NO,ROS,and apoptosis.AT3 and M4-mAChR inhibitors inhibited the H/R-induced production of NO and ROS and apoptosis.HIF-1αwas induced by H/R,but was suppressed by AT3.Conclusion:Thus,the in vitro evidence shows that AT3 protects against H/R injury in cerebral microvascular endothelial cells via inhibition of HIF-1α,NO and ROS,predominantly through the downregulation of M4-mAChR.The findings offer novel understandings regarding AT3-mediated attenuation of endothelial cell apoptosis and cerebral ischemia/reperfusion injury.

Offspring of rats with cerebral hypoxia-ischemia manifest cognitive dysfunction in learning and memory abilities

Neonatal hypoxic-ischemic encephalopathy is a serious neurological disease,often resulting in long-term neurodevelopmental disorders among surviving children.However,whether these neurodevelopmental issues can be passed to offspring remains unclear.The right common carotid artery of 7-day-old parental-generation rats was subjected to permanent ligation using a vessel electrocoagulator.Neonatal hypoxic-ischemic rat models were established by subjecting the rats to 8%O2–92%N2 for 2 hours.The results showed that 24 hours after hypoxia and ischemia,pathological damage,cerebral atrophy,liquefaction,and impairment were found,and Zea-Longa scores were significantly increased.The parental-generation rats were propagated at 3 months old,and offspring were obtained.No changes in the overall brain structures of these offspring rats were identified by magnetic resonance imaging.However,the escape latency was longer and the number of platform crossings was reduced among these offspring compared with normal rats.These results indicated that the offspring of hypoxic-ischemic encephalopathy model rats displayed cognitive impairments in learning and memory.This study was approved by the Animal Care&Welfare Committee of Kunming Medical University,China in 2018(approval No.kmmu2019072).

An animal model of cerebral palsy induced by prenatal exposure to lipopolysaccharide and hypoxia

BACKGROUND： Neonatal cerebral palsy is mainly caused by prenatal factors. At present, an animal model of prenatal infection and early postnatal hypoxia does not exist. OBJECTIVE： To observe morphology and motor performance following prenatal infection and hypoxic insult-induced brain damage of neonatal rats to verify the feasibility to establish a model of cerebral palsy. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratories of Xinjiang Center for Disease Control and Prevention from September 2007 to June 2008. MATERIALS： The hypoxic incubator was purchased from Shanghai Pediatric Medical Institute, China. Lipopolysaccharide （LPS, Escherichia coil, 055： B5） was purchased from Sigma-Aldrich （St. Louis, MO, USA）. METHODS： A total of 27 Wistar rats, aged 7 days, were randomly assigned to sham-surgery group （n = 15） with no carotid artery incision or hypoxia treatment, hypoxia/ischemia （H/I） group （n = 12） undergoing ligature of the right common carotid artery followed by exposure to hypoxia at postnatal day 7 （P7）, and LPS/H group （n = 19）, in which pregnant rats were exposed in utero to LPS followed by prenatal hypoxia at embryonic day 16. MAIN OUTCOME MEASURES： Behavior, compound muscle action potential, and pathological changes were observed in 28-day-old rats. RESULTS： The footprint repeat space showed that left limb footprint repeatability in the H/I and LPS/H groups was lower than in the sham-surgery group （P 〈 0.05）. The space between the footprints was larger and unstable. Hind limb quadricep compound muscle action potential in the H/I and LPS/H groups showed lower wave amplitude compared with the sham-surgery group （P〈 0.05） Hematoxylin and eosin staining showed irregular cells around the ventricle, as well as periventricular leukomalacia. CONCLUSION： An animal model of cerebral palsy was established, which simulated the human condition most likely associated with occurrence of this disease. This model could be used for experimental studies related to cerebral palsy.

Changes of hypoxia-inducible factor-1 signaling and the effect of cilostazol in chronic cerebral ischemia

Hypoxiainducible factor1 and its specific target gene heme oxygenase1, are involved in acute cerebral ischemia. However, very few studies have examined in detail the changes in the hy poxiainducible factor1/heme oxygenase1 signaling pathway in chronic cerebral ischemia. In this study, a rat model of chronic cerebral ischemia was established by permanent bilateral common carotid artery occlusion, and these rats were treated with intragastric cilostazol （30 mg/kg） for 9 weeks. Morris water maze results showed that cognitive impairment gradually worsened as the cerebral ischemia proceeded. Immunohistochemistry, semiquantitative PCR and western blot analysis showed that hypoxiainducible factorla and heme oxygenase1 expression levels in creased after chronic cerebral ischemia, with hypoxiainducible factorla expression peaking at 3 weeks and heme oxygenase1 expression peaking at 6 weeks. These results suggest that the elevated levels of hypoxiainducible factorla may upregulate heine oxygenase1 expression fol lowing chronic cerebral ischemia and that the hypoxiainducible factor1/heme oxygenase1 sig naling pathway is involved in the development of cognitive impairment induced by chronic cerebral ischemia. Cilostazol treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, decreased hypoxiainducible factorla and heme oxygenase1 expression levels, and reduced apoptosis in the frontal cortex. These findings demonstrate that cilostazol can protect against cognitive impairment induced by chronic cerebral ischemic injury through an antiapoptotic mechanism.

A rat pup model of cerebral palsy induced by prenatal inflammation and hypoxia

Animal models of cerebral palsy established by simple infection or the hypoxia/ischemia method cannot effectively simulate the brain injury of a premature infant. Healthy 17-day-pregnant Wistar rats were intraperitoneally injected with lipopolysaccharide then subjected to hypoxia. The pups were used for this study at 4 weeks of age. Simultaneously, a hypoxia/ischemia group and a control group were used for comparison. The results of the footprint test, the balance beam test, the water maze test, neuroelectrophysiological examination and neuropathological examination demonstrated that, at 4 weeks after birth, footprint repeat space became larger between the forelimbs and hindlimbs of the rats, the latency period on the balance beam and in the Morris water maze was longer, place navigation and ability were poorer, and the stimulus intensity that induced the maximal wave amplitude of the compound muscle action potential was greater in the lipopolysaccharide/hypoxia and hypoxia/ischemia groups than in the control group. We observed irregular cells around the periventricular area, periventricular leukomalacia and breakage of the nuclear membrane in the lipopolysacchadde/hypexia and hypoxia/ischemia groups. These results indicate that we successfully established a Wistar rat pup model of cerebral palsy by intraperitoneal injection of lipopolysaccharide and hypoxia.

Expression of hypoxia inducible factor-1 alpha and ischemic erythropoietin tolerance in the brain of cerebral ischemic tolerance model rats

BACKGROUND： Hypoxia inducible factor-1 alpha （HIF-1 （x） and erythropoietin（EPO）, possessing neuroprotective effect in the cerebral ischemia, might play an important role in the formation of cerebral ischemic tolerance （IT）. OBJECTIVE：To observe the neuroprotective effect of cerebral ischemic preconditioning（IPC） of rats, and the expression and mechanism of HIF-1α and target gene erythropoietin in the brain tissue following the formation of cerebral IT. DESIGN ： A randomized and controlled observation SETTING： Department of Neurology, the Affiliated Hospital of Medical College, Qingdao University MATERIALS： Totally 84 enrolled adult healthy male Wistar rats of clean grade, weighing 250 to 300 g, were provided by the Animal Experimental Department, Tongji Medical College of Huazhong University of Science and Technology. Ready-to-use SABC reagent kit and rabbit anti-rat HIF-1α monoclonal antibody were purchased from Boshide Bioengineering Co.Ltd （Wuhan）; Rabbit anti-rat EPO monoclonal antibody was purchased from Santa Cruz Company （USA）. METHODS： This experiment was carried out in the Department of Anatomy, Medical College, Qingdao University during March 2005 to March 2006. ① The 84 rats were divided into 3 groups by a lot： IPC group （n=40）, sham-operation group （n=40） and control group （n=4）. In the IPC group, middle cerebral artery was occluded for 2 hours respectively on the 1^st, 3^rd, 7^th, 14^th and 21^st days of the reperfusion following 10-minute preischemia was made using a modified middle cerebral artery second suture method from Zea-Longa. The rats were sacrificed 22 hours after reperfusion in the end of middle cerebral artery occlusion （MCAO）. That was to say, after 10-minute preischemia, suture was exited to the extemal carotid artery and embedded subcutaneously. Middle cerebral artery was occluded again to form the second reperfusion at the set time point after reperfusion. Twenty-two hours later, rats were sacrificed; In the sham-operation group,the preischemia was substituted by sham-operation（only common carotid artery and crotch were exposed, and MCAO by suture was omitted）, and the other procedures were the same as those in the IPC group. In the control group, rats were given sham-operation twice at an interval of one day, and they were sacrificed 24 hours after the second sham-operation. ② Brain tissue was taken from the rats in each group. Cerebral infarction area of each layer was measured with TTC staining, and total cerebral infarction volume （The total cerebral infarction area of each layerxinterspace ） was calculated. After brain tissue was stained by haematoxylin-esoin （HE）, the form of nerve cells was observed under an optical microscope, and the expressions of HIF-1α（and EPO protein in the brain tissue were detected with immunohistochemical method. MAIN OUTCOME MEASURES： ①Cerebral infarction volume;②form of nerve cell; ③ the expression of HIF-1α and EPO protein in the brain tissue. RESULTS：Totally 84 rats were enrolled in the experiment. The dead rats were randomly supplied during the experiment, and finally 84 rats entered the stage of result analysis. ① Detection of cerebral infarction volume of rats in each group： Cerebral infarction volume in the IPC group was significantly smaller than that in the sham-operation group on the 1^st, 3^rd and 7^th days after reperfusion respectively [（161.2±6.9） mm^3 vs （219.9±11.2） mm^3, （134.9±9.0） mm^3 vs （218.6±13.0） mm^3, （142.9±13.7） mm^3 vs （221.3±14.2） mm^3, t=-8.924, 10.587,7.947, P〈 0.01]. ② Observation of nerve cell form of brain tissue： HE staining showed that the ischemic degree, range and cerebral edema degree of IPC group were significantly milder than those of sham-operation group. ③ The expressions of HIF-1α and EPO protein in cerebral cortex and hippocampus ： The expression of HIF-1αof IPC group was significantly higher than that of sham-operation group on the 1^st, 3^rd and 7^th days after reperfusion respectively （125.93±3.79 vs 117.65±5.60, 140.63±4.64 vs 119.33±4.26, 131.15±2.74 vs 107.60±3.89, t=2.449, 6.763,9.899,P 〈 0.05-0.01）. The expression of EPO of IPC group was significantly higher than that of sham-operation group on the 3^rd and 7^th days after perfusion respectively （141.68±3.29 vs 126.33±4.51, 138.88±2.59 vs 125.58±6.18,t=5.499,3.970, P〈 0.05）. CONCLUSION ： ①IPC can protect the never cells in rat brain and the best time to onset of cerebral IT induced by IPC is 1 to 7 days after reperfusion. ② Neuroprotective effect of cerebral IT might be related to the expression of HIF-1α and its target gene EPO.

Expression of c-Fos protein and nitricoxide synthase in neurons of cerebral cortex from fetal rats in hypoxia and protective role of Angelica sinensis

BACKGROUND： Both c-Fos protein and nitricoxide synthase （NOS） have been used as general indexes in relative research about neurons, but it is lack of reports that c-Fos protein and NOS are applied synchronously to study the neurons of hypoxic fetal rats in uterus. OBJECTIVE： To study the effect of hypoxia in uterus on the expression of c-Fos protein and NOS in neurons of cerebral cortex from fetal rats and whether Angelica sinensis has the protective effect on these neurons in hypoxia. DESIGN： Randomized control experiment.SETTING ： Department of Histology and Embryology, Luzhou Medical College.MATERIALS ： Twelve adult female Wistar rats in oestrum and 1 male Wistar rat with bodymass from 220 to 250 g were chosen. Parenteral solution of Angelica sinensis mainly contained angelica sinensis, 10 mL/ampoule, was provided by Department of Agent of the Second Hospital Affiliated to Hubei Medical University （batch number： 01062310）. METHODS ： This experiment was completed in the Department of Histology and Embryology of Luzhou Medical College from September 2003 to June 2004. ①Twelve adult female Wistar rats in oestrum and 1 male Wistar rat were housed in one rearing cage. Vaginal embolus was performed on conceive female rat at 8： 00 am next day. On the 15^th conceiving day, all conceiving rats were divided randomly into three groups： control group, hypoxia group and Angelica group with 4 in each group. Rats in hypoxia group and Angelica group were modeled with hypotonic hypoxia in uterus. Angelica group： Rats were injected with 8 mL/kg Angelica sinensis injection through caudal veins before hypoxia. Hypoxia group： Rats were injected with the same volume of saline. Control group： Rats were not modeled and fed with normal way. ② Twenty embryos of rats were chosen randomly from each group and then routinely embedded in paraffin. Paraffin sections were cut from the brain of embryos to anterior fontanelle. Double-label staining was used to detect the expression of nNOS and c-Fos in neurons of cerebral cortex from embryos of rats. OLYMPUS Bx-50 microscope was used to observe sections and DP12 digit camera was also used under 400 times to detect types of cells. Under microscope, the number of c-Fos, NOS, c-Fos/NOS positive neurons in cerebral cortex from embryos of rats were counted in 2 fields with magnification of 400 in one section per animal. ③ The data in experiments were analyzed by one-way analysis of variance （ANOVA） followed by q test. MAIN OUTCOME MEASURES： ① Results of immunohistochemical double-label staining of c-Fos/NOS from cerebral cortex; ② Comparison of amount immunohistochemical double-label staining of c-Fos/NOS positive cells from cerebral cortex. RESULTS：① The positive NOS cells and c-Fos/NOS cells in the three groups were mainly distributed in cerebral cortex, but positive c-Fos neurons were not observed. ② Positive NOS cells and c-Fos/NOS cells in hypoxia group were more than those in control group （76.55±12.02, 50.45±10.39; 33.35±7.42, 26.35±6.67, P 〈 0.05）, but those in Angelica group were less than those in hypoxia group （51.70±9.82, 35.65±8.37, P 〈 0.05）. CONCLUSION： Hypoxia can stimulate the increase of expression of c-Fos protein and NOS in neurons of cerebral cortex. However, Angelica sinensis can decrease this expression so as to play a protective role in cerebral neurons of hypoxic fetal rats.

Effects of L-Tetrahydropalmatine on NOSⅢ Gene Expression in Hypoxia and Cultured Porcine Cerebral Arterial Endothelial Cells during Reoxygenation

To investigate the expression of NOSⅢ mRNA and protein in cultured porcine cerebral arterial endothelial cells (CAEC) during hypoxia and reoxygenation and the effects of L-Tetrahydropalmatine (L-THP) on the gene expression of NOSⅢ in CAEC during hypoxia and reoxygenation. The cultured CAEC were divided into 5 groups: control, hypoxia, hypoxia+reoxygenation, hypoxia+L-THP and reoxygenation+L-THP groups. NOSⅢ mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR). Immunocytochemistry was used to detect the level of NOSⅢ protein. The expression of NOSⅢ mRNA and protein were increased when CAEC were exposed to hypoxia for 1 h, and significantly decreased during reoxygenation 2, 6 and 12 h after 1-h of hypoxia. L-THP from 10 -8 mol/L to 10 -3 mol/L could inhibit the up-regulation of NOSⅢ gene expression during hypoxia and down-regulation of NOSⅢ gene expression during reoxygenation.

Factors Accounting for Different Responses of Pulmonary and Cerebral Vessels to Hypoxia

The roles of sympathicus, sensory neuropeptides (SNP),cyclooxygenase metabolites (COX-M), lipoxygenase metabolites (LOX-M), endothelium derived relaxing factor (EDRF),reactive oxygen (ROS) and potassium channels (PC) in the hypoxic pulmonary vasoconstriction (HPV) and hypoxic cerebral vasodilation (HCVD) were investigated in intact rats, rabbits and dogs. The results showed that during hypoxia,the excitation of sympathicus caused a constriction of both pulmonary and cerebral vessels,while SNP, EDRF and the opening of voltage sensitive PC caused the dilation of both of them; LOX-M mediated HPV and HCVD, COX-M might serve as their modulators; the blockade of ATP sensitive PC induced by hypoxia mediated HPV, but had no effect on HCVD; the reduction of O_2￣- in the lung might potentiate HPV, however, O_2￣- remained unchanged in brain during hypoxia. It is suggested that the alterations of LOX-M,ROS and the ATP sensitive PC are the factors accounting for the difference in the response of pulmonary and cerebral vessels to hypoxia.

Correlation of hypoxia-inducible factor-1 alpha and erythropoietin protein and mRNA to cerebral ischemic tolerance in a focal ischemia/reperfusion model using the twice suture method

BACKGROUND： Numerous studies have shown that transient ischemic preconditioning induces cerebral ischemic tolerance. However, the underlying mechanisms of endogenous protection following ischemic preconditioning remain unclear. OBJECTIVE： To dynamically measure erythropoietin and hypoxia-inducible factor-1α （HIF-1α） mRNA and protein expression at various times following preconditioning, and to investigate effects of erythropoietin and HIF-1α on cerebral ischemic tolerance in a model of focal ischemia/reperfusion established using the twice suture method. DESIGN, TIME AND SETTING： The randomized, controlled study was performed at the Institute of Anatomy, Medical College, Qingdao University, China from March 2006 to March 2007. MATERIALS： Rabbit anti-rat HIF-1α monoclonal antibody and biotinylated goat anti-rabbit IgG （Boster, China）, rabbit anti-rat erythropoietin monoclonal antibody （Santa Cruz Biotechnology, USA）, and one-step RT-PCR kit （Qiagen, Germany） were used in this study. METHODS： A total of 99 healthy, male, Wistar rats were randomly assigned to three groups： sham surgery （n = 9）, non-ischemic preconditioning （n = 45）, and ischemic preconditioning （n = 45）. In the ischemic preconditioning group, rat models of pre-ischemia-reperfusion-ischemia-reperfusion were established by occluding the left middle cerebral artery using the twice suture method. In the non-ischemic preconditioning group, pre-ischemia was replaced by sham surgery. Subsequently, the ischemic preconditioning and non-ischemic preconditioning groups were equally divided into five subgroups according to time of first reperfusion, including 1-, 3-, 7-, 14-, and 21-day subgroups. The sham surgery group received the sham surgery twice. MAIN OUTCOME MEASURES： HIF-la and erythropoietin protein expression was measured in the cerebral cortex, corpus striatum, and hippocampus of the ischemic hemisphere. HIF-1α and erythropoietin mRNA expression were determined in the frontal and parietal cortex of the ischemic hemisphere. RESULTS： （1） Intergroup comparison： compared with the non-ischemic preconditioning group, HIF-1α protein expression significantly increased in the rat cerebral cortex, corpus striatum, and hippocampus in the ischemic hemisphere at 1,3, and 7 days following reperfusion in the ischemic preconditioning group （P 〈 0.05 or P 〈 0.01）. Erythropoietin protein expression significantly increased in the cerebral cortex, corpus striatum, and hippocampus, as well as HIF-1α and erythropoietin mRNA expression in the frontal and parietal cortex in the ischemic hemisphere, at 3 and 7 days following reperfusion in the ischemic preconditioning group （P 〈 0.05）. （2） Temporal expression： HIF-1α protein expression in the rat cerebral cortex, corpus striatum, and hippocampus, as well as HIF-la mRNA expression in the frontal and parietal cortex, in the ischemic hemisphere increased at 3 days, and gradually decreased from 7 days following reperfusion in the ischemic preconditioning group. Temporal erythropoietin protein and mRNA expression was consistent with HIF-1α protein expression. （3） Correlation： erythropoietin mRNA expression positively correlated with HIF-1α mRNA expression （r= 0.737, P 〈 0.01）. CONCLUSION： Ischemic preconditioning induced cerebral ischemic tolerance. Pre-ischemiainduced increase in endogenous HIF-1αexpression, as well as its target gene erythropoietin, participated in the formation of cerebral ischemic tolerance.

Protective effect of Angelica sinensis on cerebral neurons from rat embryos under hypoxia

BACKGROUND： The enhanced expression of c-Fos protein in nerve cells after hypoxia is the marker for converting extracellular hypoxia information to intracellular changes at hypoxia, and it is suspected that the increase of c-Fos protein can lead to the synthesis and excretion of related neurotrophic factor and nerve growth factor. However, it is still unclear what functional changes of nerve cells are induced by the increase of c-Fos protein at hypoxia, and whether it is good for the survival of damaged neurons. OBJECTIVE： To observe the expression of c-Fos in the cerebral neurons from embryos of rats with hypoxia in uterus, and investigate the pathway for the protective effect of Angelica sinensis injection on the cerebral neurons from rat embryos under hypoxia. DESIGN： A completely randomized controlled study. SETTING： Department of Histology and Embryology, Luzhou Medical College. MATERIALS： Twelve female Wistar rats in oestrum and 1 male adult Wistar rat with body mass of 220 to 250 g were selected. Rabbit-anti-rat neuro-specific enolase （NSE） and rabbit-anti-rat c-Fos were purchased from Wuhan Boster Biological Technology Co., Ltd.; Double-staining kit was bought from Beijing Zhongshan Golden Bridge Biotechnology Co., Ltd. Angelica sinensis injection was produced by the Department of Pharmacy, the Second Affiliated Hospital of Hubei Medical University. METHODS： The experiments were completed in the experimental animal center and the Department of Histology and Embryology of Luzhou Medical College from December 2004 to December 2005. ①Twelve adult female Wistar rats in oestrum and 1 male Wistar rat were housed in one rearing cage. The appearance of vaginal embolus at 8：00 in the next morning was recorded as 0 day of pregnancy and the rats were recorded for 15 days, and they were divided randomly into three groups, control group （n =4）, hypoxia group （n =4） and Angelica group （n =4）. The pregnant rats in the hypoxia group were firstly injected with saline （8 mL/kg）, then put into 2 L wide-mouthed bottle containing 100 g sodalime, and then the lid of the bottle was closed tightly to induce hypotonic hypoxia for 1 hour followed by 1-hour re-oxygenation. The pregnant rats were killed under anesthesia, and then fetuses were taken out by rapid cesarean. Part of the brain tissues were exposed and then fixed in formaldehyde （40 g/L）. The pregnant rats in the Angelica group were treated the same as those in the hypoxia group except that saline was replaced by 250 g/L Angelica sinensis injection which was injected via caudal vein （8 mL/kg）. The rats in the control group were injected with saline （8 mL/kg） slowly via caudal vein, but not put into the wide-mouthed bottle for hypoxia, and then the brain tissues were removed and fixed as those in the hypoxia group after 1 hour. ②Twenty embryos from rats were chosen randomly in each group and then routinely embedded in paraffin. Paraffin sections of 4 μ m thick were prepared through the anterior fontanelle of head of the fetal rats. The sections were immunohistologically stained with c-Fos/NSE. ③The one-way analysis of variance （ANOVA） was used to compare the differences of measurement data among the groups, and the q test was applied in the two-two comparison. MAIN OUTCOME MEASURES： The numbers of c-Fos and c-Fos/NSE positive neurons in cerebrum from rat embryos were observed. RESULTS： ① Numbers of NSE positive neurons in cerebrum of rat embryos in the control group, hypoxia group and Angelica group were （84.3 ±9.0）, （90.2±12.5） and （86.7±9.7） cells/high power field （P 〉 0.05）. ②The number of c-Fos/NSE positive neurons was more in the hypoxia group than in the control group and Angelica group [（38.4±5.28）, （11.35±2.67）, （20.65±4.07） cells/high power field, q =29.17, 19.14, P 〈 0.05]. CONCLUSION： Hypoxia can stimulate the expression of c-Fos in cerebral neurons from rat embryos. Angelica sinensis injection could reducing the damage of hypoxia to neurons and play a neuroprotective role by decreasing the expression of c-Fos protein in hypoxic neurons.

Effect of polygonatum polysaccharide on the hypoxia-induced apoptosis and necrosis in in vitro cultured cerebral cortical neurons from neonatal rats

BACKGROUND： Cardiocerebrovascular diseases induced cerebral circulation insufficiency and senile vascular dementia can result in ischemic/hypoxic apoptosis of central neurons, which we should pay more attention to and prevent and treat as early as possible. Traditional Chinese medicine possesses the unique advantage in this field. Polygonatum, a Chinese herb for invigorating qi, may play a role against the hypoxic apoptosis of brain neurons. OBJECTIVE ： To observe the protective effect of polygonatum polysaccharide on hypoxia-induced apoptosis and necrosis in cerebral cortical neurons cultured in vitro. DESIGN： A comparative experiment.SETTING： Laboratory of Cell Biology, Institute of Basic Medical Sciences, Jiangxi Provincial Academy of Traditional Chinese Medicine. MATERIALS： The experiment was carried out in the Laboratory of Cell Biology, Institute of Basic Medical Sciences, Jiangxi Provincial Academy of Traditional Chinese Medicine from November 2003 to April 2005. Totally 218 Wistar rats （male or female） of clean degree within 24 hours after birth were purchased from the animal center of Jiangxi Medical College （certification number was 021-97-03）. METHODS：① Preparation of cerebral cortical neurons of rats： The cerebral cortical tissues were isolated from the Wistar rats within 24 hours after birth, and prepared to single cell suspension, and the cerebral cortical neurons of neonatal rats were in vitro cultured in serum free medium with Neurobasal plus B27 Supplement. ② Observation on the non-toxic dosage of polygonatum polysaccharide on neurons： After the neurons were cultured for 4 days, polygonatum polysaccharide of different dosages （1-20 g/L） was added for continuous culture for 48 hours, the toxicity and non-toxic dosage of polygonatum polysaccharide on neurons were observed and detected with trypan blue staining. ③Grouping： After hypoxia/reoxygenation, the cultured neurons were divided into normal control group, positive apoptotic group and polygonatum polysaccharide group. In the normal control group, the neurons were cultured at 37℃ in CO2 with the volume fraction of 0.05 under saturated humidity for 6 days. In the apoptotic positive group, the neurons were cultured with hypoxia for 12 hours after 4-day culture, and followed by reoxygenation for 48 hours. In the polygonatum polysaccharide group, polygonatum polysaccharide with the terminal concentration of 0.5, 1 and 1.5 g/L was added to some neurons at 10 hours before the hypoxia culture, and then the neurons were cultured with hypoxia for 12 hours, followed by reoxygenation for 48 hours; polygonatum polysaccharide with the terminal concentration of 0.5, 1 and 1.5 g/L was added to the other neurons at 12 hours after hypoxia followed by reoxygenation for 48 hours.④ The Hoechst33342 fluorescence staining, Annexin V/PI flow cytometer, appearance of DNA agarose gel electrophoresis gradient strap and immunohistochemical staining were used to observe the expressions of Bcl-2, Bax and Caspase-3 apoptotic and anti-apoptotic proteins and the ratio of Bcl-2/Bax, and observe the effect of polygonatum polysaccharide against the hypoxic apoptosis of cerebral cortical neurons of neonatal rats. MAIN OUTCOME MEASURES： ① Toxicity and non-toxic dosage of polygonatum polysaccharide on neurons;② Apoptotic rate of neurons detected with Hoechst33342 fluorescence staining;③ Early apoptotic rate and necrotic rate of neurons detected with Annexin V/PI flow cytometer; ④DNA agarose gel electrophoresis ladder-like strap appeared or not;⑤ Expressions of Bcl-2, Bax and Caspase-3 apoptotic and anti-apoptotic proteins and the ratio of Bcl-2/Bax. RESULTS：① Polygonatum polysaccharide within 6 g/L had no cytotoxicity on the normal cultured cerebral cortical neurons （P 〉 0.05）. ②The apoptotic rates of neurons detected with Hoechst33342 fluorescence staining had significant differences between the polygonatum polysaccharide groups and positive apoptosis group added to neurons at 10 hours before the hypoxia culture [（13.00±4.52）%,（12.72±2.15）%, （11.80±1.18）%,（38.03±1.05）%, P 〈 0.01], and had no significant differences between the polygonatum polysaccharide groups and positive apoptosis group added to neurons at 12 hours after the hypoxia culture （36.77±1.45）%, （36.60±1.61）%, （36.37±2.02）%, （38.03±1.05）%, P 〉 0.05].③ Annexin V/PI flow cytometer detected that the anti-necrotic effect was enhanced with the increased concentration of polygonatum polysaccharide within 0.5-1.5 g/L （P 〈 0.01）. Polygonatum polysaccharide of 0.5-1.5 g/L added before hypoxia could significantly decrease the apoptotic rate of neurons induced by hypoxia/reoxygenation （P 〈 0.01）. ④ No DNA agarose gel electrophoresis ladder-like strap appeared in the groups with polygonatum polysaccharide of 0.5-1.5 g/L added at 10 hours before hypoxia;⑤ After Polygonatum polysaccharide of 0.5-1.5 g/L was added before hypoxia, the expression of Bcl-2 protein of hypoxic neurons was increased （P 〈 0.01）, and those of Bax protein and Caspase-3 protein were reduced （P 〈 0.01）, and the ratio of Bcl-2/Bax was increased （P 〈 0.01）. CONCLUSION： Polygonatum polysaccharide within 6 g/L has no cytotoxicity on the normal cultured cerebral cortical neurons. Polygonatum polysaccharide of 0.5-1.5 g/L added before hypoxia plays a role agains necrosis of neurons induced by hypoxia. Polygonatum polysaccharide of 0.5-1.5 g/L can significantly reduce the apoptosis of neurons induced by hypoxia through up-regulating the expression of Bcl-2 protein, down-regulating the expressions of Bax protein and Caspase-3 protein, and increasing the ratio of Bcl-2/Bax.

Effects of recombinant adenovirus-mediated hypoxia-inducible factorlalpha gene on proliferation and differentiation of endogenous neural stem cells in rats following intracerebral hemorrhage

Objective:To investigate the effects of adenovirus(Ad)-mediated hypoxia-inducible factor-1alpha(HIF-1α)gene on proliferation and differentiation of endogenous neural stem cells(NSCs)in rats following intracerebral hemorrhage(ICH)and the underlying mechanisms.Methods:A total of 120 specific pathogen-free,adult,male Sprague-Dawley rats were included in this study.After establishment of ICH models in rats,PBS,Ad,or Ad-HIF-1αwas administered via the ischemic ventricle.On the 1st,7th,14th,21st and 28th d after ICH,rat neurological deficits were scored,doublecortin(DCX)expression in the subventricular zone cells was detected by immunohistochemical staining,and 5-bromo-2'-deoxyuridine(Brdtl)-,BrdU/DCX-,and BrdU/glial fibrillary acidic prolein-posilive cells in the subventricular zone were counted using immumofluorescence method among PBS,Ad,and Ad-HIF-1αgroups.Results:On the 7th,14th,21st and 28th d after ICH,neurological deficit scores in the Ad-HIF-1αgroup were significantly lower than in the PBS and Ad groups(P<0.05).In the Ad-HIF-lαgroup,DCX expression was significantly increased on the 7th d,peaked on the 14th d,and then gradually decreased.In the Ad-HIF-1αgroup,BrdU-positive cells were significantly increased over time course,and significant difference in BrdU-positive cell counts was observed when compared with the PBS and Ad groups at each time point(P<0.01 or 0.05).On the 7th,14th,21st and 28th d after ICH,the number of DCX-,BrdU-,BrdU/DCX-,and BrdU/DCX-positive cells in the Ad-HIF-1αgroup was significantly greater than in the PBS and Ad groups(P<0.05).Conclusions:HIF-1αgene can promote the proliferation,migration and differentiation of endogenous neural stem cells after ICH,thereby contributing to neurofunctional recovery after ICH.

Dynamic changes in cerebral microcirculation and hypoxia in the early stages of diffuse axonal injury

This study demonstrated that damage to the cerebral microvasculature, the formation of microthrombi and swelling of vascular endothelial cells occur early and peak 12 hours after injury in a rat model of diffuse axonal injury. Moreover, these pathological changes were most evident in the cerebral cortex. Cerebral microcirculatory dysfunction peaked later and had a shorter duration than axonal injury. In addition, the radioactive imaging agent, 99Tcm-4, 9-diaza-2, 3, 10, 10- tetramethyldodecan-2, 11 -dione dioxime, was used to visualize the dynamic changes that occur in tissue with cerebral hypoxia. The results demonstrated that cerebral hypoxia occurs at an early stage in diffuse axonal injury. Cerebral hypoxia was evident 12 hours after injury and declined slightly 24 hours after injury, but was significantly higher than in the control group. The pathological changes that underpin microcirculatory dysfunction did not occur at the same time as axonal injury, but did occur simultaneously with neuronal injury. Cerebral hypoxia plays a key role in promoting the secondary brain injury that occurs after diffuse axonal injury.

Effects of Chinese herbal monomers on oxidative phosphorylation and membrane potential in cerebral mitochondria isolated from hypoxia-exposed rats in vitro

Mitochondrial dysfunction is the key pathogenic mechanism of cerebral injury induced by high-altitude hypoxia. Some Chinese herbal monomers may exert anti-hypoxic effects through enhancing the efficiency of oxidative phosphorylation, in this study, effects of 10 kinds of Chinese herbal monomers on mitochondrial respiration and membrane potential of cerebral mitochondria isolated from hypoxia-exposed rats in vitro were investigated to screen anti-hypoxic drugs. Rats were exposed to a low-pressure environment of 405.35 mm Hg （54.04 kPa） for 3 days to establish high-altitude hypoxic models. Cerebral mitochondria were isolated and treated with different concentrations of Chinese herbal monomers （sinomenine, silymarin, glycyrrhizic acid, baicalin, quercetin, ginkgolide B, saffron, pipedne, ginsenoside Rgl and oxymatrine） for 5 minutes in vitro. Mitochondrial oxygen consumption and membrane potential were measured using a Clark oxygen electrode and the rhodamine 123 fluorescence analysis method, respectively. Hypoxic exposure significantly decreased the state 3 respiratory rate, respiratory control rate and mitochondrial membrane potential, and significantly increased the state 4 respiratory rate. Treatment with saffron ginsenoside Rgl and oxymatrine increased the respiratory control rate in cerebral mitochondria isolated from hypoxia-exposed rats in dose-dependent manners in vitro, while ginsenoside Rgl, piperine and oxymatrine significantly increased the mitochondrial membrane potential in cerebral mitochondria from hypoxia-exposed rats. The Chinese herbal monomers saffron, ginsenoside Rgl piperine and oxymatrine could thus improve cerebral mitochondrial disorders in oxidative phosphorylation induced by hypobaric hypoxia exposure in vitro.

The Role of Vitamin E in Cerebral Hypoxia: An Ultrastructural Study

Hypoxia, due to impaired cerebral blood flow, has hazardous effects on brain structure and function. To minimize as much as possible the neurological consequences from hypoxic-ischemic (HI) brain injury, neuro-protective strategies are urgently required. Vitamin E has been shown to have protective effects against cerebral ischemia, possibly due to its anti-oxidant effects. Thirty albino rats, of both sexes, were obtained from the animal house at King Khalid University Hospital, King Saud University. They were divided into three groups;each included 10 animals: Group A was considered as a control one, animals of Group B were subjected to a permanent link to the carotid arteries on both sides and animals of Group C underwent permanent link to carotid arteries on both sides and concomitantly were given Vitamin E as an anti-oxidant. Animals of Group C were injected by Vitamin E (equivalent to 15 mg/day), into the peritoneal cavity as a single dose for a week and after the prescribed period the mice were sacrificed under deep anesthesia and their brains were extracted and prepared for an electron microscopic study of brain tissue. Specimens from animals of Group B showed a large number of neurons that had been deteriorated. Mitochondria were the most affected organelles. There were a large number of dark cells which probably resulted from shrunken nerve cells and exhibited opaque nuclei. The number of affected nerve cells was much lower in brain tissues from animals of the Group C which revealed absence of dark cells. The study did not disclose any similar changes in brain tissues of the control group animals. Our results suggested that treatment with Vitamin E after hypoxia-ischemia led to a neuro-protective effect that appeared in reduction of cell death of neurons. Thus, the present study provides an evidence that Vitamin E protects the brain tissue of the consequences of hypoxia caused by ischemia in the tested experimental animals. It could be recommended in the treatment of cerebrovascular stroke and neurodegenerative diseases.

Early identification of acute hypoxia based on brain NADH fluores cence and cerebral blood flow

Hypoxia is closely related to many diseases and often leads to death.Early detection andidentification of the hypoxia causes may help to promptly determine the right rescue plan andreduce the mortality.We proposed a new multiparametric monitoring method employingmitochondrial reduced nicotinamide adenine dinucleotide(NA DH)fluorescence,regional reflectance,regional cerebral blood flow(CBF),electrocardiography(ECG),and respiration under sixkinds of acute hypoxia in four categories to investigate a correlation bet ween the parametervariances and the hypoxia causes.The variation patterns of the paramet ers were discussed,andthe combination of NADH and CBF may contribute to the identification of the causes of hypoxia.

Effect of pre-ischemia on hypoxia-inducible factor expression in the brain tissue of rats with cerebral ischemia/reperfusion injury

Hypoxia-inducible factor 1 （HIF-1） can lead to the adaptative reaction of body for hypoxia and ischemia. HIF-1 plays an important role in the response of ischemia-hypoxia. At present, there has been no overall report on the significance for the expression of HIF-1 following experimental cerebral ischemia. OBJECTIVE： To observe the expression of HIF-1 after middle cerebral artery occlusion （MCAO） by immunohistochemical method. DESIGN： Completely randomly grouped controlled animal experiment. SETTING： Second Hospital, Xi＇an Jiaotong University. MATERIALS： Thirty-six Sprague-Dawley healthy male rats, with body mass of 250 - 330 g, were used in this study. Thirty-six rats were randomized into 3 groups： preischemia group, sham-operation group and control group, with 12 rats in each. METHODS： This study was carried out in the clinical laboratory, People＇s Hospital of Ningjin County of Shandong Province from March 2006 to January 2007. Rats in the pre-ischemia group were created into preischemia models by two embolisms twice. Three days after ischemic preconditioning, middle cerebral artery （MCA） was occluded for 2 hours with the same method. After being perfused for 22 hours, the rats were euthanized. In the sham-operation group, rats were not given the treatment of preischemia. In the first operation, only common carotid artery （CCA） and its crotch were exposed in the first operation, and MCA was not blocked by inserting embolism. At postoperative 3 days, rats were euthanized after being subjected to MCAO for 2 hours and reperfusion 22 hours by the same procedure as that in the preischemia group. As for each rat in the control group, only CCA and its crotch were exposed, and no any other treatment was carried out on them. MAIN OUTCOME MEASURES： Brain tissue of each rat was performed immunohistochemical staining at reperfusion 22 hours after preischemia, HIF-1 expression and brain infarct volume were detected. RESULTS： Thirty-six Sprague-Dawley rats were involved in the experiment. During the experiment, 8 rats dropped out, and another 8 rats were supplemented. The infarct volume of rats in the preischemia group was significantly smaller than that in the sham-operation group （t=3.22, P 〈 0.01 ） . HIF-1 expression was not found in the control group, but many HIF-I positive cells were found in the other two groups. Absorbance in the preischemia group was significantly higher than that in the sham-operation group （t=4.31, P 〈 0.01）. CONCLUSION： Slight ischemia caused preconditioning can increase HIF-1 content, and it is one of protective mechanisms for nerve cells.

Corrigendum: Offspring of rats with cerebral hypoxia-ischemia manifest cognitive dysfunction in learning and memory abilities

In“Offspring of rats with cerebral hypoxia-ischemia manifest cognitive dysfunction in learning and memory abilities”,which was published on pages 1662-1670,Issue 9,Volume 15 of Neural Regeneration Research(Xue et al.,2020),Figure 1A appears incorrectly because of the author’s error made in image selection.

Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine（BrdU） incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.