Treatment with β-sitosterol ameliorates the effects of cerebral ischemia/reperfusion injury by suppressing cholesterol overload, endoplasmic reticulum stress, and apoptosis

β-Sitosterol is a type of phytosterol that occurs naturally in plants.Previous studies have shown that it has anti-oxidant,anti-hyperlipidemic,anti-inflammatory,immunomodulatory,and anti-tumor effects,but it is unknown whetherβ-sitosterol treatment reduces the effects of ischemic stroke.Here we found that,in a mouse model of ischemic stroke induced by middle cerebral artery occlusion,β-sitosterol reduced the volume of cerebral infarction and brain edema,reduced neuronal apoptosis in brain tissue,and alleviated neurological dysfunction;moreover,β-sitosterol increased the activity of oxygen-and glucose-deprived cerebral cortex neurons and reduced apoptosis.Further investigation showed that the neuroprotective effects ofβ-sitosterol may be related to inhibition of endoplasmic reticulum stress caused by intracellular cholesterol accumulation after ischemic stroke.In addition,β-sitosterol showed high affinity for NPC1L1,a key transporter of cholesterol,and antagonized its activity.In conclusion,β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.

A feasible strategy for focal cerebral ischemiareperfusion injury: remote ischemic postconditioning

It is difficult to control the degree of ischemic postconditioning in the brain and other isch- emia-sensitive organs. Remote ischemic postconditioning could protect some ischemia-sensitive organs through measures on terminal organs. In this study, a focal cerebral ischemia-reperftlsion injury model was established using three cycles of remote ischernic postconditioning, each cycle consisted of 10-minute occlusion of the femoral artery and 10-minute opening. The results showed that, remote ischemic postconditioning significantly decreased the percentage of the in- farct area and attenuated brain edema. In addition, inflammatory nuclear factor-KB expression was significantly lower, while anti-apoptotic Bcl-2 expression was significantly elevated in the ce- rebral cortex on the ischemic side. Our findings indicate that remote ischemic postconditioning attenuates focal cerebral ischemia/reperfusion injury, and that the neuroprotective mechanism is mediated by an anti-apoptotic effect and reduction of the inflammatory response.

A molecular probe carrying anti-tropomyosin 4 for early diagnosis of cerebral ischemia/reperfusion injury

In vivo imaging of cerebral ischemia/reperfusion injury remains an important challenge.We injected porous Ag/Au@SiO_(2) bimetallic hollow nanoshells carrying anti-tropomyosin 4 as a molecular probe into mice with cerebral ischemia/reperfusion injury and observed microvascular changes in the brain using photoacoustic imaging with ultrasonography.At each measured time point,the total photoacoustic signal was significantly higher on the affected side than on the healthy side.Twelve hours after reperfusion,cerebral perfusion on the affected side increased,cerebrovascular injury worsened,and anti-tropomyosin 4 expression increased.Twenty-four hours after reperfusion and later,perfusion on the affected side declined slowly and stabilized after 1 week;brain injury was also alleviated.Histopathological and immunohistochemical examinations confirmed the brain injury tissue changes.The nanoshell molecular probe carrying anti-tropomyosin 4 has potential for use in early diagnosis of cerebral ischemia/reperfusion injury and evaluating its progression.

Electroacupuncture preconditioning protects against focal cerebral ischemia/reperfusion injury via suppression of dynamin-related protein 1

Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.

Inhibition of cerebral ischemia/reperfusion injuryinduced apoptosis:nicotiflorin and JAK2/STAT3 pathway

Nicotiflorin is a flavonoid extracted from Carthamus tinctorius.Previous studies have shown its cerebral protective effect,but the mechanism is undefined.In this study,we aimed to determine whether nicotiflorin protects against cerebral ischemia/reperfusion injury-induced apoptosis through the JAK2/STAT3 pathway.The cerebral ischemia/reperfusion injury model was established by middle cerebral artery occlusion/reperfusion.Nicotiflorin（10 mg/kg） was administered by tail vein injection.Cell apoptosis in the ischemic cerebral cortex was examined by hematoxylin-eosin staining and terminal deoxynucleotidyl transferase d UTP nick end labeling assay.Bcl-2 and Bax expression levels in ischemic cerebral cortex were examined by immunohistochemial staining.Additionally,p-JAK2,p-STAT3,Bcl-2,Bax,and caspase-3 levels in ischemic cerebral cortex were examined by western blot assay.Nicotiflorin altered the shape and structure of injured neurons,decreased the number of apoptotic cells,down-regulates expression of p-JAK2,p-STAT3,caspase-3,and Bax,decreased Bax immunoredactivity,and increased Bcl-2 protein expression and immunoreactivity.These results suggest that nicotiflorin protects against cerebral ischemia/reperfusion injury-induced apoptosis via the JAK2/STAT3 pathway.

Vascular endothelial growth factor induced angiogenesis following focal cerebral ischemia/reperfusion injury in rabbits

BACKGROUND： Therapeutic angiogenesis has opened up new pathway for the treatment of ischemic cerebrovascular disease in recent years. The exploration of the effect of vascular endothelial growth factor （VEGF） on inducing angiogenesis following ischemia/reperfusion injury can provide better help for the long-term treatment of cerebrovascular disease in clinic. OBJECTIVE： To observe the effect of VEGF on inducing angiogenesis following focal cerebral ischemia /reperfusion injury in rabbits through the angiogenesis of microvessels reflected by the expression of the factors of vascular pseudohemophilia. DESIGN： A randomized controlled animal tria SETTNG： Department of Medical Imaging, Second Hospital of Hebei Medical University MATERIALS： Sixty-five healthy male New Zealand rabbits of clean degree, weighing （2.6±0.2） kg, aged 4.5-5 months, were used. The polyclonal antibody against vascular pseudohemophilia （Beijing Zhongshan Company）, recombinant VEGF165 （Peprotech Company, USA）, biotinylated second antibody and ABC compound （Wuhan Boster Company） were applied. METHODS： The experiments were carried out in the Laboratory of Neuromolecular Imaging and Neuropathy, Second Hospital of Hebei Medical University from May to August in 2005. （1） The rabbits were randomly divided into three groups： sham-operated group （n=15）, control group （n=25） and VEGF-treated group （n=-25）. In the control group and VEGF-treated group, models were established by middle cerebral artery occlusion （MCAO） induced focal cerebral ischemia/reperfusion. In the VEGF-treated group, VEGF165 （2.5 mg/L） was stereotactically injected into the surrounding regions of the infarcted sites immediately after the 2-hour ischemia/reperfusion; Saline of the same dosage was injected in the control group. But the rabbits in the sham-operated group were only drilled but not administrated. （2） The experimental indexes were observed on the 3^rd 7^th, 14^th, 28^th and 70^th days of the experiment respectively, 3 rabbits in the sham-operated group and 5 in the control group and VEGF-treated group were observed at each time point. The brain tissues in the surrounding regions of the infarcted sites were collected. The positive expressions of the factors of vascular pseudohemophilia in vascular endothelial cells were analyzed with immunohistochemical method. The microvessels in unit statistical field were counted with the imaging analytical software. MAIN OUTCOME MEASURES： The changes of microvascular density in the brain tissue and the positive expressions of the factors of vascular pseudohemophilia in the surrounding regions of the infarcted sites were observed on the 3^rd 7^th, 14^th, 28^th and 70^th days of the experiment. RESULTS： All the 65 New Zealand rabbits were involved in the analysis of results without deletion. Changes of the number of microvessels at different time points in each group： There were no obvious changes at different time points in the sham-operated group. The numbers of microvessels at 7 and 14 days were obviously more in the control group than in the sham-operated group [（6.0±1.1）, （9.0±0.9） microvessels; （3.0±1.1）, （3.0±1.1） microvessels; P〈 0.05-0.01], and those at 3, 7, 14 and 28 days were obviously more in the VEGF-treated group than in the control group [（8.3±2.0）, （13.4±1.4）, （15.5±2.3）, （6.8± 1.0） microvessels; （3.4±0.6）, （6.0±1.1）, （9.0±0.9）, （3.2±0.8） microvessels; P 〈 0.01]. （2） Positive expressions of the factors of vascular pseudohemophilia in the surrounding regions of infarcted sites： There were no obvious changes at different time points in the sham-operated group. In the control group, the changing law of the expressions was the same as that for the number of microvessels that the expression began to mildly increase at 7 days, reached the peak value at 14 days, and began to reduce at 28 days. In the VEGF-treated group, the expression was obviously increased at 3 days, also reached the peak value at 14 days, and reduced to the normal level at 70 days, but the expressions were obviously stronger than those in the control group at the same time points. CONCLUSION： Angiogenesis can be obviously induced in rabbits after the focal cerebral ischemia/reperfusion injury is treated with VEGF for 18 days.

Acupuncture effects on serum myelin basic protein and remyelination following 30 minutes and 2 hours of ischemia in a rat model of cerebral ischemia-reperfusion injury

BACKGROUND： Acupuncture treatment on injured cerebral axons has shown to provide efficacy in clinical practice. It is unknown whether acupuncture produces therapeutic effects by protecting injured cerebral myelin in ischemic stroke. OBJECTIVE： To test whether acupuncture provides protection for injured cerebral myelin, based on quantitative data from cerebral ischemia-reperfusion rats, and to compare the effects of early and late acupuncture on serum myelin basic protein （MBP） content and remyelination of the ischemic internal capsule.DESIGN, TIME AND SETTING： A randomized, controlled experiment was performed at the Neurobiological Laboratory, Sichuan University from March 2005 to March 2006. MATERIALS： ＂Hua Tuo＂ Brand filiform needles were produced by the Medical Instrument Factory of Suzhou, China.METHODS： A total of 52 adult, healthy, male, Sprague Dawley rats were randomly assigned to four groups： control （n = 4）, model （n = 16）, early acupuncture （n = 16）, and late acupuncture （n = 16）. The focal cerebral ischemia-reperfusion model was established by middle cerebral artery occlusion in the right hemisphere using the modified thread embolism method in the latter three groups. Early and late acupuncture groups underwent acupuncture after ischemia for 30 minutes and 2 hours using the Xingnaokaiqiao needling method, respectively. Acupoints were ＂Neiguarf＇ （PC 6） and ＂Sanyinjiao＂ （SP 6） on the bilateral sides, as well as ＂Shuigou＇ （DU 26） and ＂Baihui＂ （DU 20） with stimulation for 1 minute at each acupoint. Acupuncture at all acupoints was performed two or three times while the needle was retained, once per day. No special handling was administered to the control clroup.MAIN OUTCOME MEASURES： For each group, remyelination of the internal capsule was observed by Pal-Weigert＇s myelin staining and serum MBP content was detected using enzyme-linked immunosorbent assay method on days 1,3, 5, and 7 following ischemia-reperfusion injury.RESULTS： Compared with the control group, massive demyelination of the internal capsule occurred, and serum MBP content increased in the model group （P 〈 0.05）. Compared with the model group, the extent of demyelination in the internal capsule was less distinct and serum MBP content was significantly less in the early and late acupuncture group （P 〈 0.01 ）. Compared with the late acupuncture group, serum MBP content reached a peak later and the peak value was less in the early acupuncture group. CONCLUSION： Results suggest that acupuncture exerts a protective effect on injured cerebral myelin in ischemia-reperfusion rats by reducing serum MBP content and promoting remyelination. The study also suggests that the effect of early acupuncture is superior to late acupuncture.

Effects of NG-nitro-L-arginine on focal cerebral ischemic injury in rats

BACKGROUND： Previous researches have proved that aminoguanidin can cure cerebral ischemic injury remarkably as a selective induced nitricoxide synthase （iNOS） inhibitor. However, whether nonselective NOS inhibitor could protect cerebral ischemic injury or not is unclear. OBJECTIVE： To investigate the effects of NG-nitro-L-arginine （L-NA）, a nonselective nitricoxide synthase （NOS） inhibitor, on cerebral ischemic injury of rats and the possible mechanism.DESIGN： Randomized controlled study.SETTING ： Pharmacological Department of Medical Academy of Science of Hebei Province.MATERIALS： A total of 56 male healthy SD rats, of grade Ⅱ, weighting 250-290 g, were provided by the Experimental Animal Center of Hebei Province （certification： 04036）. METHODS： The experiment was completed in the Pharmacological Department of Medical Academy of Science of Hebei Province from March 2005 to January 2006.① Grouping： Rats were randomly divided into 3 groups： sham operation group （n=8）, model group （n=24） and L-NA group （n=24）.② Modeling： Middle cerebral artery （MCA） was established on rats in model group and L-NA group with intreluminal line occlusion methods, and rats in sham operation group were separated their external carotid arteries without occlusion of internal carotid artery. ③ Intervention study： Rats in model group and L-NA group were injected intreperitoneally with 10 mL/kg and 20 mg/kg L-NA at 2, 6 and 12 hours respectively after ischemia twice a day for 3 consecutive days. ④ Rats were sacrificed on the third day for measuring volume of cerebral infarction with image analysis and swelling degrees and activities of mitochondria with electron microscope. Effect of L-NA on ultrastructural changes of neurons in cortex was observed after ischemia. MAIN OUTCOME MEASURES：① Volume of cerebral infarction; ②Swelling degrees, contents of nitric oxide （NO） and malondialdehyde （MDA） and activities of adenosine triphosphatase （ATPase）, superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） in mitochondria;③ Ultrastructural changes of mitochondria in brain tissue after cerebral ischemia. RESULTS： ① At 12 hour after ischemia, volume of cerebral infarction in L-NA group was lower than that in model group （P 〈 0.01）. ② Content of NO in mitochondria in L-NA group was decreased as compared with that in model group at 2, 6 and 12 hours after ischemia （P 〈 0.05）; swelling degree of mitochondria in brain tissue was relieved in L-NA group at 12 hour after ischemia, and content of MDA was decreased （P 〈 0.05）; mitochondrial activity in L-NA group was increased at 12 hour after ischemia, and activities of ATPase, SOD and GSH-Px in mitochondria were increased （P 〈 0.05）.③ Degrees of mitochondrial injury in brain tissue were relieved in L-NA group at 12 hour after ischemia as compared with those in model group and L-NA group at 2 and 6 hours after ischemia. CONCLUSION ： ①L-NA can beneficially inhibit NO production, but not protect brain against damage in ischemia acute stage. ②L-NA might have protective effects on cerebral injury through inhibiting the production of oxygen free radical, increasing antioxidation, ameliorating energy metabolism, beneficially improving the integrity of form and function of mitochondria in brain tissue during postischemia in rats.

Neuroprotective effect of ischemic preconditioning in focal cerebral infarction: relationship with upregulation of vascular endothelial growth factor

Neuroprotection by ischemic preconditioning has been confirmed by many studies, but the precise mechanism remains unclear. In the present study, we performed cerebral ischemic pre- conditioning in rats by simulating a transient ischemic attack twice （each a 20-minute occlusion of the middle cerebral artery） before inducing focal cerebral infarction （2 hour occlusion-reper- fusion in the same artery）. We also explored the mechanism underlying the neuroprotective effect of ischemic preconditioning. Seven days after ocdusion-reperfusion, tetrazolium chloride staining and immunohistochemistry revealed that the infarct volume was significantly smaller in the group that underwent preconditioning than in the model group. Furthermore, vascular endothelial growth factor immunoreactivity was considerably greater in the hippocampal CA3 region of preconditioned rats than model rats. Our results suggest that the protective effects of ischemic preconditioning on focal cerebral infarction are associated with upregulation of vascu- lar endothelial growth factor.

Buyanghuanwu decoction promotes angiogenesis after cerebral ischemia/reperfusion injury：mechanisms of brain tissue repair

Buyanghuanwu decoction has been shown to protect against cerebral ischemia/reperfusion injury,but the underlying mechanisms remain unclear.In this study,rats were intragastrically given Buyanghuanwu decoction,15 m L/kg,for 3 days.A rat model of cerebral ischemia/reperfusion injury was established by middle cerebral artery occlusion.In rats administered Buyanghuanwu decoction,infarct volume was reduced,serum vascular endothelial growth factor and integrin αvβ3 levels were increased,and brain tissue vascular endothelial growth factor and CD34 expression levels were increased compared with untreated animals.These effects of Buyanghuanwu decoction were partially suppressed by an angiogenesis inhibitor（administered through the lateral ventricle for 7 consecutive days）.These data suggest that Buyanghuanwu decoction promotes angiogenesis,improves cerebral circulation,and enhances brain tissue repair after cerebral ischemia/reperfusion injury.

Effects of reduction of Sheng-Nao-Kang decoction in focal cerebral ischemia/reperfusion model rats

Aim Reduction of Sheng-Nao-Kang decoction （RSNK）, is a modified traditional Chinese medicinal formula of Sheng-Nao-Kang pill preparation, which is protective in rats against focal cerebral ischemia/reperfusion （I/R） injury. In the current study, we investigate the protective effect of RSNK against apoptosis and oxidative damage induced by cerebral I/R and explore the underlying mechanisms. Cerebral I/R injury was induced by in- traluminal middle cerebral artery occlusion （MCAO） for 2 h followed by reperfusion for 24 h in adult male Sprague- Dawley rats. Rats were randomized into seven groups （n- 8）： Sham group, I/R group, RSNK-treated groups （ 0.7 g · kg ^- 1, 1 . 4 g · kg ^- 1 and 2. 8 g · kg^ - 1 ） , nimodipine （NMP） -treated group and Whitmania pigra Whitman （WW）-treated group. Neurological deficit scores, cerebral humidity content and cerebral infarction volume were measured after the 24 h reperfusion. Malondialdehyde （ MDA）, superoxide dismutase （ SOD）, catalase （ CAT）, inducible nitric oxide synthase （iNOS） and total nitric oxide synthase （TNOS） in serum were measured by assay kits for biochemical analysis. Histological structures of the cortex of the ipsilateral ischemic cerebral hemisphere in rats were observed by Nissl staining. The caspase-3 protein content in the hippocampus and cortex was detected by immunohistochemistry. Additionally, Bax and Bcl-2 protein expressions in the injured brain were evaluated by Western blot. RSNK administration not only markedly improved neurological deficit scores, but also reduced cere- bral humidity content and cerebral infarction volume, lowered MDA content, up-regulated SOD and CAT levels, down-regulated iNOS and TNOS levels, restrained the expression of caspase-3 positive protein and alleviated the Bax and Bcl-2 protein expressions.

Hyperlipidemia affects neuronal nitric oxide synthase expression in brains of focal cerebral ischemia rat model

BACKGROUND： Hyperlipidemia, a risk factor for ischemic cerebrovascular disease, may mediate production of neuronal nitric oxide synthase （nNOS） to induce increased nitric oxide levels, resulting in brain neuronal injury. OBJECTIVE： To investigate effects of hyperlipidemia on brain nNOS expression, and to verify changes in infarct volume and pathology during reperfusion, as well as neuronal injury following ischemia/reperfusion in a rat model of focal cerebral ischemia. DESIGN, TIME AND SETTING： Complete, randomized grouping experiment was performed at the Laboratory of Physiology, Shanxi Medical University from March 2005 to March 2006. MATERIALS： A total of 144 eight-week-old, male, Wistar rats, weighing 160-180 g, were selected. A rat model of middle cerebral artery occlusion was established by suture method after 4 weeks of formulated diet. Nitric oxide kit and rabbit anti-rat nNOS kit were respectively purchased from Nanjing Jiancheng Bioengineering Institute, China and Wuhan Boster Biological Technology, Ltd., China. METHODS： The rats were equally and randomly divided into high-fat diet and a normal diet groups. Rats in the high-fat diet group were fed a high-fat diet, consisting of 10% egg yolk powder, 5% pork fat, and 0.5% pig bile salt combined with standard chow to create hyperlipidemia. Rats in the normal diet group were fed a standard rat chow. A total of 72 rats in both groups were randomly divided into 6 subgroups： sham-operated, 4-hour ischemia, 4-hour ischemia/2-hour reperfusion, 4-hour ischemia/4-hour reperfusion, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion, with 12 rats in each subgroup. MAIN OUTCOME MEASURES： nNOS expression was measured by immunohistochemistry, and pathomorphology changes were detected by hematoxylin-eosin staining. Infarct volume and nitric oxide levels were respectively measured using 2, 3, 5-triphenyltetrazolium chloride （TTC） and immunohistochemistry. RESULTS： In the ischemic region, pathology changes were significant in the 4-hour ischemia/4-hour, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion subgroups fed on a high-fat diet compared to the same groups fed on a normal diet. In each ischemia subgroup, nNOS expression in brain tissues was higher than in the sham-operated subgroups fed on either the high-fat diet or normal diet （P 〈 0.01）. At each ischemia/reperfusion time point, rats fed on a high-fat diet expressed higher levels of nNOS compared to rats fed on the normal diet （P 〈 0.05）. When tissue was stained with TTC, a white infarction area was detected in the ischemic hemisphere, demonstrating that the infarct volume gradually increased with prolonged reperfusion time in each ischemia subgroup. At each ischemia/reperfusion time point, the infarct volume was larger in rats fed on a high-fat diet compared to those fed on a normal diet. CONCLUSION： nNOS expression was greater in hyperlipidemia rats following ischemia/reperfusion. Cerebral ischemia/reperfusion injury is aggravated with prolonged reperfusion time.

Effects of Salvia miltiorrhiza on cerebral infarction volume,nerve behavior and SOD,GSH-px,MDA,BDNF and GDNF in rats

Objective:To investigate the effects of Salvia miltiorrhiza on cerebral infarction volume,nerve behavior and brain tissue SOD,GSH-Px,MDA,GDNF,BDNF in rats with focal cerebral ischemia reperfusion injury.Methods:Healthy adult male SD rats(clean grade)80,were randomly divided into sham operation group(saline),model group(saline),low dose group(10 mg/kg salvianolate),high dose group(30 mg/kg salvianolate)and edaravone group(6 mg/kg)with 16 rats in each groups were compared after operation in rats,48 h neural behavior of 24 h and 72 h scores,cerebral infarction volume 24 h after operation;SOD,GSH-Px and other indicators of brain tissue of rats after the determination of 72 h.Results:After 24 h,low dose group,high dose group and edaravone group,the cerebral infarction volume were less than the model group,high dose group and edaravone group,the infarct volume was less than the low dose group;after 24 h,48 h,72 h,scores of neurological behavior in the low dose group and high dose group and Yidala in the study group were lower than model group,neural behavior in high dose group and edaravone group scores were lower than the low dose group;low dose group,high dose group and edaravone group in the brain tissue of SOD,GSH-Px,BDNF,GDNF were higher than that of model group,and MDA was lower than that of model group;high dose group and edaravone group in the brain tissue of SOD,GSH-Px,BDNF,GDNF were higher than those in the low dose group,and MDA was lower than that of low dose group.Conclusion:The treatment of focal cerebral ischemia reperfusion injury in rats by inhibiting lipid peroxidation,protecting Magnesium Oxide's activity,thereby reaching the therapeutic effect.

基于环磷酸腺苷/蛋白激酶A/环磷酸腺苷反应元件结合蛋白通路探究丙泊酚对局灶性脑缺血再灌注大鼠神经功能改善机制

目的:基于环磷酸腺苷/蛋白激酶A/环磷酸腺苷反应元件结合蛋白(cAMP/PKA/CREB)通路探究丙泊酚对局灶性脑缺血再灌注大鼠神经功能的改善机制。方法:采用改良线栓法缺血2 h,再灌注24 h建立大鼠脑缺血再灌注损伤(CIRI)模型,将造模成功大鼠随机分为模型组和丙泊酚低(1 mg/ml)、中(2.5 mg/ml)、高剂量(5 mg/ml)组,各12只,另设含有12只大鼠的假手术组。分组后即开始给药,1次/d,共4周,末次给药12 h后,采用改良神经功能评分(mNSS)法进行神经缺损评分;采用TTC染色法检测脑梗死面积;HE、Nissl染色进行神经元细胞及尼氏小体形态学观察;Tunel法进行神经元细胞凋亡检测;Elisa法检测脑组织cAMP、脑源性神经营养因子(BDNF)、神经生长因子(NGF)含量;免疫荧光法检测脑组织环磷酸腺苷(cAMP)、p-PKA、p-CREB阳性细胞数及其蛋白共表达阳性细胞数;Western blot法检测脑组织PKA、p-PKA、CREB、p-CREB蛋白表达量。结果:模型组大鼠比较假手术组大鼠的mNSS评分、脑梗死面积百分比显著增加(均P<0.05),HE染色和Nissl染色可见明显的神经元细胞损伤和尼氏小体破坏,脑组织cAMP、BDNF、NGF含量和PKA、p-PKA、CREB、p-CREB蛋白表达量显著下降,模型组大鼠比较假手术组大鼠的cAMP、p-PKA、p-CREB阳性细胞数和蛋白共表达阳性细胞数也明显下降(均P<0.05)。与模型组比较,丙泊酚给药组大鼠mNSS评分、脑梗死面积百分比显著降低(均P<0.05),HE染色和Nissl染色可见神经元细胞损伤和尼氏小体破坏有不同程度改善,脑组织cAMP、BDNF、NGF含量和PKA、p-PKA、CREB、p-CREB蛋白表达量显著升高(均P<0.05),cAMP、p-PKA、p-CREB阳性细胞数及其蛋白共表达阳性细胞数均显著升高(均P<0.05)。结论:丙泊酚可能通过cAMP/PKA/CREB通路改善CIRI大鼠神经功能。

杜鹃花总黄酮通过抑制TNF-α/caspase-8/caspase-3信号通路减轻大鼠脑缺血再灌注损伤的作用

目的探索杜鹃花总黄酮(TFR)通过抑制TNF-α/caspase-8/caspase-3信号通路保护脑缺血再灌注(I/R)损伤的机制。方法采用大脑中动脉闭塞术(MCAO)建立大鼠I/R模型,将造模成功大鼠随机分为假手术(Sham)、脑缺血再灌注(MCAO)和脑缺血再灌注术后TFR 200 mg/kg干预(TFR 200 mg/kg)组,制备MCAO大鼠模型,在脑缺血再灌注损伤手术后,TFR 200 mg/kg组连续14 d给予TFR(200 mg/kg)药物溶液。术后14 d,依据大鼠神经功能评分,脑血流图观察脑血流情况,处死大鼠,苏木精-伊红(HE)染色观察脑组织细胞形态学变化,试剂盒检测大鼠血清中乳酸脱氢酶(LDH或LD)和神经特异性烯醇化酶(NSE)两种酶活性;ELISA试剂盒检测白细胞介素-1(IL-1)和IL-6水平,Western blot和免疫组化同时检测大鼠脑组织中裂解型胱天蛋白酶3(cleaved caspase-3)、caspase-8、肿瘤坏死因子(TNF)-α蛋白的表达水平。结果脑缺血再灌注处理后,MCAO导致了大鼠神经功能异常,神经功能评分指数显著升高,脑组织病理形态学和脑血流量变化明显,脑组织中cleaved caspase-3、caspase-8、TNF-α蛋白的表达水平显著增加,血清中LDH、NSE、IL-1、IL-6水平明显升高;TFR 200 mg/kg组大鼠神经功能评分明显降低,脑组织病理损伤显著改善,脑组织中cleaved caspase-3、caspase-8、TNF-α蛋白的表达以及血清中LDH、NSE、IL-1、IL-6水平降低。结论TFR可能通过抑制TNF-α/caspase-8/caspase-3信号通路减轻脑缺血缺氧性损伤。

温阳复元方通过调控miRNA-137/线粒体铁死亡通路保护大鼠脑缺血再灌注损伤机制研究

目的探讨温阳复元方对miRNA-137/线粒体铁死亡通路的调控作用,阐明该方对脑缺血再灌注损伤(CIRI)的神经保护作用机制。方法线栓法制备大鼠CIRI模型,将144只SD大鼠随机分为假手术(SO)组、模型(I/R)组、补阳还五汤对照(BYHW)组、温阳复元方(WYFY)组、温阳复元方+miRNA-137模拟物(WYFY+mimic)组、温阳复元方+miRNA-137抑制物(WYFY+Inhibitor)组,每组按再灌注时间点分为3个亚组。采用Zea-Longa评分法进行神经功能缺损评分(NFS);TTC染色测量脑梗死体积;qRT-PCR和Western blot法观察miRNA-137、膜铁转运蛋白(FPN)和二价金属离子转运体1(DMT1)的mRNA及其蛋白表达水平。结果(1)NFS结果:I/R组NFS较SO组显著增加(P<0.01),与I/R组相比,BYHW组NFS仅在12 h时评分降低(P<0.05),而WYFY组在24 h和3 d的NFS明显降低(P<0.05或P<0.01),WYFY+mimic组NFS显著下降(P<0.01),WYFY+Inhibitor组在3 d时NFS降低(P<0.05);与WYFY组相比,WYFY+mimic组NFS仅在12 h时明显降低(P<0.05)。(2)TTC染色结果:I/R组梗死体积较SO组显著增大(P<0.01),BYHW组和WYFY组较I/R组明显减小(P<0.05或P<0.01),WYFY组梗死体积较BYHW组进一步减小(P<0.01);相较于WYFY组,WYFY+mimic组能进一步减小其梗死体积(P<0.05),而WYFY+Inhibitor组梗死灶明显增大(P<0.05)。(3)miRNA-137 mRNA表达水平:I/R组miRNA-137mRNA的表达较SO组显著下降(P<0.01),WYFY治疗后其表达量显著增加(P<0.01),且WYFY组其表达水平较BYHW组进一步增高(P<0.01);与WYFY组同期比较,WYFY+mimic组miRNA-137 mRNA表达量均进一步升高(P<0.01),WYFY+Inhibitor组抑制该表达(P<0.01)。(4)FPN mRNA及蛋白表达水平:I/R组FPN mRNA和蛋白表达水平较SO组均降低(P<0.01),WYFY组能显著增加其表达(P<0.01),该组在12 h和3 d时的表达量较BYHW组进一步增加(P<0.05或P<0.01);与WYFY组同期对比,WYFY+mimic组其表达水平在24 h及3 d时增加(P<0.01),而WYFY+Inhibitor组其表达水平均降低(P<0.01)。(5)DMT1 mRNA及蛋白表达水平:I/R组DMT1mRNA和蛋白表达量较SO组均显著增加(P<0.01);与I/R组比较,WYFY能降低其表达水平(P<0.01),且WYFY组在3 d时其表达量较BYHW组进一步降低(P<0.05);与WYFY组同期相比,WYFY+mimic组其表达水平在24 h和3 d时均降低(P<0.01),而WYFY+Inhibitor组其表达水平均显著增加(P<0.01)。结论温阳复元方可能通过上调miRNA-137的表达,进而上调铁转运蛋白FPN的表达,下调DMT1的表达,调节铁代谢,最终抑制线粒体铁死亡,发挥其神经保护作用,其疗效优于补阳还五汤。

壮药双路通脑方对脑缺血再灌注损伤大鼠神经元凋亡的影响

目的 基于氧化应激和炎症反应探讨壮药双路通脑方对脑缺血再灌注损伤大鼠神经元凋亡的影响。方法 将大鼠随机分为假手术组,模型组,壮药双路通脑方低、中、高剂量组(9.0、18.0、36.0 g/kg),依达拉奉组(3.0 mg/kg),每组18只,采用线栓法构建大脑中动脉闭塞/再灌注模型以模拟脑缺血再灌注损伤,给予相应药物干预6 d,采用Zeal Longa评分法对大鼠进行神经功能缺损评分,TTC染色检测脑梗死面积,HE染色和TUNEL染色检测脑组织缺血半暗带海马CA1区神经元病理损伤和细胞凋亡情况,试剂盒检测脑组织SOD活性和GSH、MDA、IL-6、IL-1β、TNF-α水平,Western blot法检测大鼠脑组织Bax、Bcl-2、caspase-3、cleaved-caspase-3、TLR4、NF-κB p65、Nrf2、HO-1蛋白表达。结果 与模型组比较,壮药双路通脑方中、高剂量组和依达拉奉组大鼠神经功能缺损评分,脑梗死率,神经元凋亡率,脑组织缺血半暗带IL-6、IL-1β、TNF-α、MDA水平,Bax、TLR4蛋白表达,cleaved-caspase-3/caspase-3、p-NF-κB p65/NF-κB p65比值降低(P<0.05),GSH水平、SOD活性和Bcl-2、Nrf2、HO-1蛋白表达升高(P<0.05)。结论 壮药双路通脑方可抑制氧化应激和炎症反应,抑制神经元凋亡,改善神经功能,减轻脑缺血再灌注损伤大鼠的脑损伤,其机制可能与抑制TLR4/NF-κB信号通路和激活Nrf2/HO-1信号通路有关。

抑制水通道蛋白4表达对脑缺血再灌注模型小鼠自噬和凋亡的影响

目的:探讨抑制水通道蛋白4(AQP4)表达对脑缺血再灌注模型小鼠自噬和凋亡的影响及其机制。方法:采用暂时性大脑中动脉闭塞(tMCAO)建立小鼠脑缺血再灌注损伤模型。将60只小鼠按随机数字表法分成假手术(sham)组、I/R组、AQP4抑制组和自噬抑制剂3-甲基腺嘌呤(3-MA)组,每组15只,sham组和I/R组腹腔注射生理盐水,AQP4抑制组和3-MA组分别腹腔注射AER-271(2 mg·kg^(-1)·d^(-1))和AER-271+3-MA(2 mg·kg_(-1)·d^(-1)),给药3 d,每天1次。观察各组小鼠神经功能Longa评分,记录体重变化;采用苏木精-伊红(HE)染色法观察脑梗死体积及组织病理变化;采用Western blot检测AQP4、LC3-Ⅱ、P62和cleaved caspase 3含量变化,采用免疫荧光法检测LC3-Ⅱ、P62、cleaved caspase-3与NeuN(神经元标志物)的共定位及表达情况。结果:I/R组与AQP4抑制组检测到大面积的脑梗塞和脑水肿,以及较高的Longa评分;与I/R组比较,AQP4抑制组的脑梗塞体积、脑水肿体积和Longa评分均显著降低(P<0.05);与sham组比较,I/R组的AQP4、LC3-Ⅱ和cleaved caspase-3的表达显著增加(P<0.01),而小鼠体重和P62表达则显著降低(P<0.05,P<0.01)。与I/R组比较,AQP4抑制组和3-MA组的AQP4、LC3-Ⅱ和cleaved caspase-3表达显著降低(P<0.05,P<0.01),而小鼠体重和P62表达则显著增加(P<0.05,P<0.01)。然而,与AQP4抑制组比较,3-MA组小鼠Longa评分、脑梗死体积、小鼠体重和AQP4、LC3-Ⅱ、cleaved caspase-3及P62的表达无显著差异。结论:抑制AQP4的表达能够显著减小tMCAO模型小鼠的脑梗死面积和减轻神经损伤程度。同时,抑制AQP4的表达对脑梗死后自噬和凋亡具有减缓作用,而加用自噬抑制剂后对AQP4抑制剂的保护作用无显著影响。

西格列汀对局灶性脑缺血再灌注小鼠血-脑脊液屏障通透性的影响及抗凋亡作用

目的研究西格列汀(SIT)在非糖尿病的小鼠脑缺血再灌注(I/R)时的神经保护作用。方法采用大脑中动脉栓塞(MCAO)模型,脑缺血60 min后实施再灌注。SIT按低剂量(40 mg·kg^(-1))、高剂量(80 mg·kg^(-1))在手术前口服给药3d,术后再次给药。术后24 h检测小鼠神经功能、梗死体积和脑水肿,通过Western blot评估Bcl-2和Akt的蛋白表达,RT-qPCR评估Bax和Bcl-2的转录水平。SIT对血-脑脊液屏障(BCFB)通透性的影响通过伊文思蓝渗出和Claudin-5的蛋白表达来测量。结果本研究结果表明,SIT可减轻CD-1小鼠大脑中动脉栓塞再灌注24h后的肢体功能障碍,减少脑梗死体积,减轻脑水肿。SIT显著增加Bcl-2和磷酸化Akt的蛋白表达水平,下调Bax、上调Bcl-2的基因表达。减少小鼠脑组织伊文思蓝渗出并增加Claudin-5的蛋白表达水平(~均P<0.05)。结论SIT在非糖尿病小鼠的脑I/R急性期,降低神经功能缺损评分、减少脑梗死体积、保护BCFB,具有脑保护作用,机制可能与抗凋亡有关。这些发现为急性缺血性脑血管病的治疗提供新的策略。

加味孔圣枕中丹含药血清调控SIRT1/PGC-1α通路改善氧糖剥夺再灌注PC12细胞的线粒体功能

目的基于SIRT1/PGC-1α通路探讨加味孔圣枕中丹含药血清对氧糖剥夺再灌注(OGD/R)损伤PC12细胞的线粒体功能的改善作用及机制。方法采用大鼠PC12细胞构建体外OGD/R细胞模型。细胞分组:正常组(10%FBS)、模型组(10%FBS)、10%含药血清组、5%含药血清组(5%含药血清+5%空白血清)、10%空白血清组(对照组)。采用CCK-8法检测细胞存活率,筛选合适的氧糖剥夺时间(2、4、6、8 h);MTT法检测细胞活性;线粒体压力测试(MST)法检测细胞氧气消耗速率(OCR);流式细胞术(Annexin V-PE/7-AAD双染法)检测细胞凋亡情况;Western Blot法检测PC12细胞SIRT1、PGC-1α蛋白表达水平。结果与正常组比较,氧糖剥夺2、4、6、8 h后的PC12细胞活性均明显下降(P<0.05),选择氧糖剥夺6 h作为后续实验造模时间。与正常组比较,模型组的细胞活性明显下降(P<0.05);细胞基础呼吸值、最大呼吸值、质子漏、ATP产生、备用呼吸能力的OCR值均明显降低(P<0.05);细胞凋亡率明显升高(P<0.05);细胞中SIRT1、PGC-1α蛋白表达水平明显下降(P<0.05)。与模型组比较,加味孔圣枕中丹10%、5%含药血清组的细胞活性明显提高(P<0.05);细胞基础呼吸值、最大呼吸值、质子漏、ATP产生、备用呼吸能力的OCR值均明显升高(P<0.05);细胞凋亡率明显降低(P<0.05);细胞中SIRT1、PGC-1α蛋白表达水平明显升高(P<0.05)。结论加味孔圣枕中丹含药血清能改善OGD/R损伤PC12细胞的线粒体功能障碍,抑制神经元凋亡,促进神经元存活,其作用机制可能与激活SIRT1/PGC-1α信号通路有关。