Overexpression of C-terminal fragment of glutamate receptor 6 prevents neuronal injury in kainate-induced seizure via disassembly of Glu R6-PSD95-MLK3 signaling module

Our previous study showed that when glutamate receptor （GluR）6 C terminus-containing peptide conjugated with the human immunodeficiency virus Tat protein （GluR6）-9c is delivered into hippocampal neurons in a brain ischemic model, the activation of mixed lineage kinase 3 （MLK3） and c-Jun NH2-terminal kinase （JNK） is inhibited via GluR6-postsynaptic density protein 95 （PSD95）. In the present study, we investigated whether the recombinant adenovirus （Ad） carrying GluR6c could suppress the assembly of the GluR6-PSD95-MLK3 signaling module and decrease neuronal cell death induced by kainate in hippocampal CA1 subregion. A seizure model in Sprague-Dawley rats was induced by intraperitoneal injections of kainate. The effect of Ad- Glur6-9c on the phosphorylation of INK, MLK3 and mitogen-activated ldnase kinase 7 （MKK7） was observed with western immunoblots and immunohistochemistry. Our findings revealed that overexpression of GluR6c inhibited the interaction of GluR6 with PSD95 and prevented the kainate-induced activation of INK, MLK3 and MKK7. Furthermore, kainate-mediated neuronal cell death was significantly suppressed by GluR6c. Taken together, GluR6 may play a pivotal role in neuronal cell death.

Neuronal injury and brain-derived neurotrophic factor expression in a rat model of amygdala kindling seizures Differences in brain regions and kindling courses

BACKGROUND：Studies have demonstrated that brain-derived neurotrophic factor （BDNF） has a dual effect on epilepsy. However, the relationship between epilepsy-induced brain injury and BDNF remains poorly understood.OBJECTIVE：According to ultrastructural and molecular parameters, to detect the degree of neuronal injury and BDNF expression changes at different brain regions and different kindling times to determine the effects of BDNF on epilepsy-induced brain injury.DESIGN, TIME AND SETTING：A randomized, controlled, animal experiment based on neuropathology and molecular biology was performed at the Department of Physiology and Department of Pathology, Basic Medical College of Jilin University in 2003.MATERIALS：UltraSensitiveTM SP kit for immunohistochemistry （Fuzhou Maxim Biotechnology, China）, BDNF antibody （concentrated type, Wuhan Boster Biological Technology, China）, JEM-1000SX transmission electron microscopy （JEOL, Japan）, and BH-2 light microscope （Olympus, Japan） were used in the present study.METHODS：Wistar rats were randomly assigned to control （n = 6）, sham-surgery （n = 6）, and model （n = 60） groups. The control group rats were not treated; an electrode was embedded into the amygdala in rats from the sham-surgery and model groups; an amygdala kindling epilepsy model was established in the model group.MAIN OUTCOME MEASURES：Pathological changes in the temporal lobe and hippocampus were observed by light and electron microscopy at 1, 3, 7, 14, and 21 days following kindling, and BDNF expression in the various brain regions was determined by immunohistochemistry.RESULTS：In the model group, temporal lobe cortical and hippocampal neurons were swollen and the nuclei were laterally deviated. There were also some apoptotic neurons 3 days after kindling. The nucleoli disappeared and the nuclei appeared broken or lysed, as well as slight microglia hyperplasia, at 7 days. Electron microscopic observation displayed chromatin aggregation in the nuclei and slight mitochondrion swelling 3 days after kindling. Injury changes were aggravated at 7 days, characterized by broken cytoplasmic membrane and pyknosis. With the development of seizure, the number of BDNF-positive neurons in the hippocampus and temporal lobe increased and peaked at 7 days. Moreover, hippocampal and cortical temporal lobe injury continued. Following termination of electrical stimulation after 7 days of kindling, BDNF expression decreased, but continued to be expressed, up to 21 days of kindling. In addition, the number of temporal and hippocampal BDNF-positive neurons was greater than the control group.CONCLUSION：Brain injury and BDNF expression peaked at 7 days after kindling, and hippocampal changes were significant.

The metabolic brain network in patients with Parkinson's disease based on ^(18)F-FDG PET imaging: evaluation of neuronal injury and regeneration

Over the past two decades, the development of functional imaging methods has greatly promoted our understanding on the changes of neurons following neurodegenerative disorders, such as Parkin- son＇s disease （PD）. The application of a spatial covariance analysis on 18F-FDG PET imaging has led to the identification of a distinc- tive disease-related metabolic pattern. This pattern has proven to be useful in clinical diagnosis, disease progression monitoring as well as assessment of the neuronal changes before and after clinical treatment. It may potentially serve as an objective biomarker on disease progression monitoring, assessment, histological and func- tional evaluation of related diseases.

Icariin Ameliorates D-galactose-induced Cell Injury in Neuron-like PC12 Cells by Inhibiting MPTP Opening

Objective Icariin(ICA)has a good neuroprotective effect and can upregulate neuronal basal autophagy in naturally aging rats.Mitochondrial dysfunction is associated with brain aging-related neurodegenerative diseases.Abnormal opening of the mitochondrial permeability transition pore(mPTP)is a crucial factor in mitochondrial dysfunction and is associated with excessive autophagy.This study aimed to explore that ICA protects against neuronal injury by blocking the mPTP opening and down-regulating autophagy levels in a D-galactose(D-gal)-induced cell injury model.Methods A cell model of neuronal injury was established in rat pheochromocytoma cells(PC12 cells)treated with 200 mmol/L D-gal for 48 h.In this cell model,PC12 cells were pre-treated with different concentrations of ICA for 24 h.MTT was used to detect cell viability.Senescence associatedβ-galactosidase(SA-β-Gal)staining was used to observe cell senescence.Western blot analysis was performed to detect the expression levels of a senescence-related protein(p21),autophagy markers(LC3B,p62,Atg7,Atg5 and Beclin 1),mitochondrial fission and fusion-related proteins(Drp1,Mfn2 and Opa1),and mitophagy markers(Pink1 and Parkin).The changes of autophagic flow were detected by using mRFP-GFP-LC3 adenovirus.The intracellular ultrastructure was observed by transmission electron microscopy.Immunofluorescence was used to detect mPTP,mitochondrial membrane potential(MMP),mitochondrial reactive oxygen species(mtROS)and ROS levels.ROS and apoptosis levels were detected by flow cytometry.Results D-gal treatment significantly decreased the viability of PC12 cells,and markedly increased the SA-β-Gal positive cells as compared to the control group.With the D-gal stimulation,the expression of p21 was significantly up-regulated.Furthermore,D-gal stimulation resulted in an elevated LC3B II/I ratio and decreased p62 expression.Meanwhile,autophagosomes and autolysosomes were significantly increased,indicating abnormal activation of autophagy levels.In addition,in this D-gal-induced model of cell injury,the mPTP was abnormally open,the ROS generation was continuously increased,the MMP was gradually decreased,and the apoptosis was increased.ICA effectively improved mitochondrial dysfunction to protect against D-gal-induced cell injury and apoptosis.It strongly inhibited excessive autophagy by blocking the opening of the mPTP.Cotreatment with ICA and an mPTP inhibitor(cyclosporin A)did not ameliorate mitochondrial dysfunction.However,the protective effects were attenuated by cotreatment with ICA and an mPTP activator(lonidamine).Conclusion ICA inhibits the activation of excessive autophagy and thus improves mitochondrial dysfunction by blocking the mPTP opening.

Correlation between neuronal injury and Caspase-3 after focal ischemia in human hippocampus

Background Cerebral ischemia is a significant clinical problem, and cerebral ischemia usually causes neuron injury such as apoptosis in various brain areas, including hippocampus. Cysteinyl aspartate-specific protease (Caspases) are fundamental factors of apoptotic mechanism. Caspase-3 inhibitors show effect in attenuating brain injury after ischemia. But all the results were from animal models in research laboratories. This study aimed at investigating the correlation between the change of ischemic neuronal injury and Caspase-3 post-ischemia in human hippocampus. Methods We selected and systematized 48 post-mortem specimens from 48 patients, who died of cerebral infarction. Morphological change was firstly analyzed by observing hematoxyline/eosin-staining hippocampal sections. The expression of Caspase-3 was investigated using the methods of in situ hybridization and immunohistochemistry. Terminal deoxynucleotidyl transferase-mediated 2’-deoxyuridine 5’-triphosphate-biotin nick-end labeling (TUNEL) method was used to clarify the involvement of Caspase-3 in neuron death. The loss of MAP 2 (MAP-2) was applied to judging the damaged area and degree of neuronal injury caused by ischemia.Results In the CA1 sector of hippocampus, Caspase-3 immunostaining modestly increased at 8 hours [8.05/high-power field (hpf)], dramatically increased at 24 hours (24.85/hpf), decreased somewhat after 72 hours. Caspase-3 mRNA was detectable at 4 hours (6.75/hpf), reached a maximum at 16 hours (17.60/hpf), faded at 72 hours. TUNEL-positive cells were detectable at 24 hours (10.76/hpf), markedly increased at 48-72 hours. The loss of MAP-2 was obviously detected at 4 hours, progressed significantly between 24 and 72 hours; MAP-2 immunoreactivity was barely detectable at 72 hours. Before 72 hours, the Caspase-3 evolution was related with the upregulation of TUNEL and the loss of MAP-2. The positive correlation between Caspase-3 mRNA and TUNEL was significant at the 0.05 level (correlation coefficient was 0.721); the negative correlation between Caspase-3 mRNA and MAP-2 was significant at the 0.05 level (correlation coefficient is 0.857). In the early stage (before 72 hours), the staining of Caspase-3 mRNA and immunohistochemistry was predominantly present in cytoplasm; the staining of TUNEL was predominantly localized in nucleus. At 4-16 hours, most neurons in hippocampal CA1 areas had relatively normal morphology; at 24-48 hours, neurons showed apoptotic morphology; at 72 hours, most cells showed significantly pathological morphology. Conclusions There exist a time-dependent evolution of neuronal damage after hippocampal ischemia in human brain, which was characterized by its close correspondence to Caspase-3.

Treatment of radiation-induced brain injury with bisdemethoxycurcumin

Radiation therapy is considered the most effective non-surgical treatment for brain tumors.However,there are no available treatments for radiation-induced brain injury.Bisdemethoxycurcumin(BDMC)is a demethoxy derivative of curcumin that has anti-proliferative,anti-inflammatory,and anti-oxidant properties.To determine whether BDMC has the potential to treat radiation-induced brain injury,in this study,we established a rat model of radiation-induced brain injury by administe ring a single 30-Gy vertical dose of irradiation to the whole brain,followed by intraperitoneal injection of 500μL of a 100 mg/kg BDMC solution every day for 5 successive weeks.Our res ults showed that BDMC increased the body weight of rats with radiation-induced brain injury,improved lea rning and memory,attenuated brain edema,inhibited astrocyte activation,and reduced oxidative stress.These findings suggest that BDMC protects against radiationinduced brain injury.

Ocimum sanctum extract preserves neuronal echotexture and controls seizure in lithium-pilocarpine induced status epilepticus rats

Objective:To investigate the effect of Ocimum sanctum hydroalcoholic extract(OSHE)on seizure control and neuronal injury in rats with lithium-pilocarpine-induced status epilepticus(SE).Methods:SE was induced by administering lithium chloride followed by pilocarpine 24 h later.OSHE was administered either alone or in combination with valproate(VPA)3 days before SE induction until 14 days post-SE induction.Seizure parameters were recorded on day 1(0-3 h),day 1-3 and day 4-14 post-SE.On day 14 post-SE,neurobehavioural tests(elevated plus maze and passive avoidance)were done followed by total antioxidant capacity,neuron-specific enolase,immunohistochemistry,and electron microscopic assessment in the hippocampus and cortex tissue.Results:OSHE+VPA provided more significant seizure protection(75%)than VPA(62.5%),OSHE(62.5%),or SE control(12.5%)(overall P=0.003).The latency to stage-3/4 seizures was increased and the number of stage-3/4 seizures was reduced in all treatment groups compared to the SE control group(P=0.002 and<0.001,respectively).The OSHE+VPA group also had better memory retention than other treatment groups(P<0.001)in the passive avoidance test.Total antioxidant capacity level was significantly higher and neuron-specific enolase was lower in the OSHE and OSHE+VPA groups compared to the SE control group.Electron microscopic study showed significant myelin sheath damage(67.5%,P<0.05)and axonal degeneration(51.8%,P<0.001)in the hippocampus of the SE control group,which were alleviated by OSHE or OSHE+VPA treatment.In immunohistochemical analysis,the OSHE,OSHE+VPA,and VPA groups had a significantly higher number of viable neurons and less neuronal loss compared to the SE control in the hippocampus(P<0.001).Conclusions:OSHE either alone or in combination with VPA shows better seizure control by preservation of neuronal echotexture and reducing oxidative stress in the hippocampus.

“Standby” EMT and “immune cell trapping” structure as novel mechanisms for limiting neuronal damage after CNS injury

The central nervous system （CNS） contains the two most important organs, the brain and spinal cord, for the orchestration of the mental and physical activities of life. Because of its importance, the human body has evolved barrier systems to protect CNS tissue from the external environment. This barrier is a membrane composed of tightly apposed cells and is selectively permeable to specific molecules by way of membrane transporters.

Effect of ketamine on aquaporin-4 expression and neuronal apoptosis in brain tissues following brain injury in rats

BACKGROUND： Aquaporin-4 （AQP-4） is closely related to the formation of brain edema. Neuronal apoptosis plays an important part in the conversion of swelled neuron following traumatic brain injury. At present, the studies on the protective effect of ketamine on brain have involved in its effect on aquaporin-4 expression and neuronal apoptosis in the brain tissues following brain injury in rats. OBJECTIVE： To observe the effect of ketamine on AQP-4 expression and neuronal apoptosis in the brain tissue following rat brain injury, and analyze the time-dependence of ketamine in the treatment of brain injury.DESIGN： Randomized grouping design, controlled animal tria SETTING ： Department of Anesthesiology, the Medical School Hospital of Qingdao University MATERIALS： Totally 150 rats of clean grade, aged 3 months, were involved and randomized into control group and ketamine-treated group, with 75 rats in each. Each group was divided into 5 subgroups separately at 6,12, 24, 48 and 72 hours after injury, with 15 rats at each time point. Main instruments and reagents： homemade beat machine, ketamine hydrochloride （Hengrui Pharmaceutical Factory, Jiangsu）, rabbit anti-rat AQP-4 polyclonal antibody, SABC immunohistochemical reagent kit and TUNEL reagent kit （Boster Co.,Ltd., Wuhan）. METHODS： This trial was carried out in the Institute of Cerebrovascular Disease, Medical College of Qingdao University during March 2005 to February 2006. A weight-dropping rat model of brain injury was created with Feeney method. The rats in the ketamine-treated group were intraperitoneally administered with 50 g/L ketamine （120 mg/kg） one hour after injury, but ketamine was replaced by normal saline in the control group. In each subgroup, the water content of cerebral hemisphere was measured in 5 rats chosen randomly. The left 10 rats in each subgroup were transcardiacally perfused with ketamine, then the brain tissue was made into paraffin sections and stained by haematoxylin and eosin. Neuronal morphology was observed. AQP-4 expression and neuronal apoptosis were measured with immunohistochemical method and TUNEL method respectively. MAIN OUTCOME MEASURES： Water content in brain tissue, neuronal morphology, the number of AQP-4 positive neurons and TUNEL positive neurons in rats of two groups at each time point after injury. RESULTS： Totally 150 rats entered the stage of result analysis. （1） Water content of brain tissue： The water content of brain tissue at each time point after injury in the ketamine-treated group was lower than that in the control group. There were very significant differences in water content at 12 and 24 hours after injury respectively between ketamine-treated group and control group [（77.34±2.35）% vs. （82.31 ±1.48）%; （78.01 ±2.21 ）% vs. （83.86±2.37）%, t=-4.001 6,4.036 7, both P 〈 0.01]. （2） Neuronal morphology： Pathological changes in traumatic region and peripheral region of injury in the ketamine-treated group were significantly lessened, and necrotic and apoptotic cells in the ketamine-treated group were also significantly reduced as compared with control group. （3） AQP-4 expression： AQP-4 positive neurons at each time point in the ketamine-treated group were significantly less than those in the control group. There were very significant differences in AQP-4 expression at 12 and 24 hours after injury between ketamine-treated group and control group [（34.17±4.74） /visual field vs. （43.42±5.65） /visual field;（40.83±3.17） /visual field vs. （58.88±6.23） /visual field,t=3.966 3,8.165 7, both P〈 0.01]. （4） Neuronal apoptosis： TUNEL positive neurons at each time point in the ketamine-treated group were less than those in the control group. There were very significant differences in the neuronal apoptosis at 12 and 24 hours after injury between ketamine-treated group and control group [（26.25±3.04） /visual field vs. （32.75±4.39） /visual field; （29.33± 4.02） /visual field vs. （39.83±5.61） /visual field,t=-3.849 3,5.169 2,both P 〈 0.01]. CONCLUSION： Ketamine can reduce brain edema, AQP-4 expression and neuronal apoptosis following brain injury in rats, and has obvious therapeutic effect on brain injury, especially at 12 and 24 hours after injury.

Neuronal PPARαdeficiency-induced axonal mitochondrial transport defects underly isch⁃emic stroke pathology

OBJECTIVE Peroxisome proliferator activated receptor alpha(PPARα)is an important protective factor in neurovascular diseases such as ischemic stroke.Although PPARαexpression is higher in neurons than astrocytes and microglia,the pathophysiological functions of neuronal specific-PPARαin isch⁃emic stroke remains unknown.Here,we report that neuronal PPARαdeficiency is a key factor of neuronal injury.PPARαexpression markedly decreased in neurons after ischemic stroke.METHODS AND RESULTS Neuronal-specific PPARαknockout(NCKO)exacerbates neuronal damage and brain ischemic injury.PPARαdefi⁃ciency disrupts axonal microtubule organization and mitochondrial transport by decreasing the expression of dynein light chain Tctex-type 1(Dynlt1),which is implicated in cytoprotective role with damaged neurons.Furthermore,resto⁃ration of Dynlt1 expression in neurons of NCKO mice rescue mitochondrial transport disorder,cognitive deficits and brain ischemic injury asso⁃ciated with PPARαdeletion.CONCLUSION These results reveal a critical role for neuronal PPARαin ischemic brain injury by modulating axonal mitochondrial transportation.

Underlying mechanism of protection from hypoxic injury seen with n-butanol extract of Potentilla anserine L. in hippocampal neurons

The alcohol and n-butanol extract of Potentilla anserine L. significantly protects myocardium from acute ischemic injury. However, its effects on rat hippocampal neurons and the mechanism of protection remain unclear. In this study, primary cultured hippocampal neurons from neonatal rats were incubated in 95% N2 and 5% CO2 for 4 hours. Results indicated that hypoxic injury decreased the viability of neurons, increased the expression levels of caspase-9 and caspase-3 mRNA, as well as cytochrome c, Caspase-9, and Caspase-3 protein. Pretreatment with 0.25, 0.062 5, 0.015 6 mg/mL n-butanol extract of Potentilla anserine L. led to a significant increase in cell viability. Expression levels of caspase-9 and caspase-3 mRNA, as well as cytochrome c, Caspase-9, and Caspase-3 protein, were attenuated. The neuroprotective effect of n-butanol extract of Potentilla anserine L. was equivalent to tanshinone IIA. Our data suggest that the n-butanol extract of Potentilla anserine L. could protect primary hippocampal neurons from hypoxic injury by deactivating mitochondrial cell death.

Role of neuronal gap junctions in NMDA receptor-mediated excitotoxicity and ischemic neuronal death

In the mammalian central nervous system（CNS）coupling of neurons by gap junctions and the expression of neuronal gap junction protein,connexin 36（Cx36）rapidly increases（usually during 1–2 hours）following a wide range of neuronal injuries,including ischemia,traumatic brain injury（TBI）,spinal cord injury and epilepsy（reviewed in Belousov and Fontes,2013）.Pharmacological blockade or genetic elimi-nation of Cx36-containing gap junctions dramatically re- duce neuronal death in animal models of ischemia, TBI and epilepsy and prevent NMDA receptor （NMDAR）-mediated excitotoxicity （Belousov and Fontes, 2014）.

Protective effect of melatonin on neurons after oxidative-stress injury

BACKGROUND:It has been suggested that melatonin(MT)can protect secondary neuronal injury.However,the protective effect of MT on neuronal injury in ischemia/reperfusion models in vitro still has not been proved.OBJECTIVE:To investigate the protective effect of MT on central ischemic injury of nerve cells and analyze its possible mechanism.DESIGN:Contrast observational study.SETTING:Department of Biochemistry and Molecular Biology,Tongji Medical College,Huazhong University of Science and Technology.MATERIALS:Rats aged 7-8 days and weighing 10-12 g were provided by Medical Experimental Animal Center,Tongji Medical College,Huazhong University of Science and Technology.MT was provided by Sigma Company,USA.METHODS:The experiment was carried out in the Laboratory of Biochemistry and Molecular Biology,Tongji Hospital,Huazhong University of Science and Technology from October 2002 to March 2004.The effects of MT on the neurodegeneration induced by oxygen-glucose-deprivation(OGD)were tested in cultured rat cerebellar granule cells.Neuron damage was quantitatively assessed by Typan Blue exclusion and MTT assay at different time points after oxygen-glucose-deprivation(90 minutes).DNA gel electrophoresis and acridine orange stain were performed to determine the nature of cell damage.And fluorescence spectrophotometer was used for quantification of intracellular malondialdehyde(MDA)at various time intervals.MAIN OUTCOME MEASURES:Correlation between degrees of neuronal injury and reperfusion times,apoptosis,and production of MDA in cells.RESULTS:①The neuron injury was aggravated with reperfusion time.②The protective effect of MT was time-and dose-dependent when its concentration was not higher than 10μmol/L.③When neurons were exposed to OGD for 90 minutes,part of the cells exhibited typical features of apoptosis:internucleosomal DNA condensation and DNA ladder on agarose gel electrophoresis.MT added to cells recovering from OGD exerted neuroprotective action against OGD-induced apoptosis.④In OGD exposed cultures,the production of MDA burst 12 hours after OGD,while MT significantly decreased the generation of MDA(P<0.05)in a time-dependent manner.CONCLUSION:MT may have therapeutic potential in the prevention and treatment of ischemic/hypoxic neuronal damage,and this neuroprotective action may contribute to the antioxidant nature of MT.

The expression of histone deacetylases and the regenerative abilities of spinal-projecting neurons after injury

Epigenetic control of regeneration after spinal cord injury： Com- plete spinal cord injury （SCI） in humans and other mammals leads to irreversible paralysis below the level of injury, due to failure of axonal regeneration in the central nervous system （CNS）. Previous work has shown that successful axon regeneration is dependent upon transcription of a large number of regeneration-associated genes （RAGs） and transcription factors （TFs） （Van Kesteren et al., 2011）. A prominent theory in the field of axon regeneration is that the large differences in regenerative potential between peripheral nervous system （PNS） neurons, which regenerate well, and CNS neurons, which do not, reflect differences in intrinsic transcriptional net- works, rather than individual genes （Van Kesteren et al., 2011）.

Argon: a novel therapeutic option to treat neuronal ischemia and reperfusion injuries?

Neuronal injury and neuroprotection：Ischemia and reperfusion injuries in neuronal cells such as acute ischemic stroke-represent the third leading cause of death in the world.Current therapeutic concepts mainly aim to re-establish cerebral blood flow within a time window of less than 3 hours with the goal of limiting secondary brain injury.

Supplementary motor area deactivation impacts the recovery of hand function from severe peripheral nerve injury

Although some patients have successful peripheral nerve regeneration,a poor recovery of hand function often occurs after peripheral nerve injury.It is believed that the capability of brain plasticity is crucial for the recovery of hand function.The supplementary motor area may play a key role in brain remodeling after peripheral nerve injury.In this study,we explored the activation mode of the supplementary motor area during a motor imagery task.We investigated the plasticity of the central nervous system after brachial plexus injury,using the motor imagery task.Results from functional magnetic resonance imaging showed that after brachial plexus injury,the motor imagery task for the affected limbs of the patients triggered no obvious activation of bilateral supplementary motor areas.This result indicates that it is difficult to excite the supplementary motor areas of brachial plexus injury patients during a motor imagery task,thereby impacting brain remodeling.Deactivation of the supplementary motor area is likely to be a serious problem for brachial plexus injury patients in terms of preparing,initiating and executing certain movements,which may be partly responsible for the unsatisfactory clinical recovery of hand function.

Comparison of the severity of injury of hippocampal neuron in rats induced by simulated push-pull maneuver at various degrees

BACKGROUND： Push-pull effect is often caused during maneuver, and the changes of unconsciousness induced can affect or damage cerebral neurons at various degrees. OBJECTIVE： To observe the effect of simulated push-pull maneuver at various degrees on injury of hippocampal neurons in rats and analyze its phase effect. DESIGN： Randomized control study.SETTING ： Physiological Department of Jilin Medical College.MATERIALS： A total of 40 healthy male Wistar rats, of clean grade, weighting 205-300 g, aged 3-4 months, were randomly divided into control group （n=4） and three push-pull experimental groups, including ＋2 Gz group （intensity： -2 Gz to ＋2 Gz, n=12）, ＋6 Gz group （-6 Gz to ＋6 Gz, n=12） and ＋8 Gz group （-8 Gz to ＋8 Gz, n=12）.METHODS： The experiment was completed in the Physiological Department of Jilin Military Medical College from March 2002 to May 2003. ① Rats in the experimental groups were put at the specially rolling arm of animal centrifugal machine. Then, they were pushed and pulled with ±2 Gz, ±6 Gz and ±8 Gz, respectively. The jolt was 1 Gz/s. However, rats in control group were not treated with any ways. ② Stroke index and neurological evaluation were performed on rats in the experimental groups at 0.5, 6 and 24 hours after push-pull. Stroke index was 25 points in total. The higher the scores were, the severer the cerebral injury was. Neurological evaluation was 10 points in total. The higher the scores were, the severer the nerve injury was. ③ Hippocampal tissue in brain of rats were selected to cut into sections at each time points, and form and distribution of neurons were observed in hippocampal areas with HE staining. Degrees of neuronal injury in hippocampal CA1 area were assayed after push-pull at various degrees with electron microscope. ④ Measurement data were compared with t test.MAIN OUTCOME MEASURES：① Stroke index and neurological evaluation; ② form and distribution of neurons in hippocampal areas;③ degrees of neuronal injury in hippocampal CA1 area.RESULTS： A total of 40 rats were involved in the final analysis. ① Stroke index and neurological evaluation of rats in experimental groups： At 30 minutes and 6 hours after push-pull exposure, stroke index and neurological evaluation were higher in ±6Gz group and ±8 Gz group than those in control group （P 〈 0.01）, especially at 6 hours after push-pull exposure, those in ±8 Gz group were the highest at each time points [（11.00±2.16）, （5.75±1.70） points]. At 24 hours after exposure, those were decreased as compared with those within the former two time points, but the values were still higher than those in control group （P 〈 0.05-0.01）. ② Results of HE staining： At 6 and 24 hours after exposure, partially neuronal degeneration was observed in pyramidal layer in ±6 Gz group and ±8 Gz group, including crenation of neurons, tdangle or polygon, and karyopycnosis, especially the injury in ±8 Gz group was the most obvious at 6 hours after exposure. ③ Results of ultrastructure with electron microscope： Partially neuronal degeneration at various degrees was observed in hippocampal CA1 area in ±2 Gz group at 6 hours after exposure and in ±6 Gz group and ±8 Gz group at 6 and 24 hours after exposure. At 6 hours after exposure, nucleus of hippocampal neurons in ±8 Gz group was irregular and umbilication. Caryotin was aggregated, nuclear matrix was swelled and disorder, and vacuolation was also observed. Rough endoplasmic reticulum was expanded, mitochondrium was swelled, and crista was disappeared.CONCLUSION： ① Push-pull cannot damage hippocampal neurons of rats in ±2 Gz group. ② Exposure can cause injury of hippocampal neurons of rats in ±6Gz group and ±8 Gz group, especially the injury is the severest at 6 hours after exposure in ±8 Gz group and relieves gradually 24 hours later.

Protective effect of sodium valproate on motor neurons in the spinal cord following sciatic nerve injury in rats

BACKGROUND: Sodium valproate (VPA) is used to be an effective anti-epileptic drug. VPA possesses the characteristics of penetrating rapidly through the blood-brain barrier (BBB) and increasing levels of Bcl-2 and growth cone-associated protein (GAP) 43 in spinal cord. OBJECTIVE: To observe the effect of VPA on Bcl-2 expression and motor neuronal apoptosis in spinal cord of rats following sciatic nerve transection. DESIGN: Randomized controlled experiment. SETTING: Department of Hand Surgery and Microsurgery, Wuhan Puai Hospital. MATERIALS: A total of 30 male healthy SD rats of clean grade and with the body mass of 180-220 g were provided by Experimental Animal Center of Medical College of Wuhan University. Sodium Valproate Tablets were purchases from Hengrui Pharmaceutical Factory, Jiangsu. METHODS: The experiment was performed in the Central Laboratory of Wuhan Puai Hospital and Medical College of Wuhan University from February to May 2006. Totally 30 rats were randomly divided into two groups: treatment group (n =15) and model group (n =15). Longitudinal incision along backside of right hind limbs of rats was made to expose sciatic nerves, which were sharply transected 1 cm distal to the inferior margin of piriform muscle after nerve liberation under operation microscope to establish sciatic nerve injury rat models. Sodium Valproate Tablets were pulverized and diluted into 50 g/L suspension with saline. On the day of operation, the rats in the treatment group received 6 mL/kg VPA suspension by gastric perfusion, once a day, whereas model group received 10 mL/kg saline by gastric perfusion, once a day. L4-6 spinal cords were obtained at days 1, 4, 7, 14 and 28 after operation, respectively. Terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) technique and immunohistochemical method (SP method) were used to detect absorbance (A) of neurons with positive Bcl-2 expression. Apoptotic rate of cells (number of apoptotic cells/total number of cells×100%) was calculated. MAIN OUTCOME MEASURES: A value of neurons with positive Bcl-2 expression and apoptotic rate in spinal cord of rats in the two groups. RESULTS: A total of 30 SD rats were involved in the result analysis. ①expression of positive Bcl-2 neurons: A value of positive Bcl-2 neurons were 0.71±0.02, 0.86±0.04, 1.02±0.06 at days 4, 7 and 14, respectively after operation in the treatment group, which were obviously higher than those in the model group (0.62±0.03, 0.71±0.05, 0.89±0.04, t = 3.10-4.50, P < 0.05). ②apoptotic result of motor neurons: Apoptotic rate of motor neurons in spinal cord was (6.91±0.89)% and (15.12±2.34)% at days 7 and 14 in the treatment group, which was significantly lower than those in the model group [(9.45±1.61)%, (19.35±0.92)%, t = 2.39, 3.03. P < 0.05]. CONCLUSION: VPA can increase expression of Bcl-2 in spinal cord and reduce neuronal apoptosis in rats following sciatic nerve injury, and has protective effect on motor neuron in spinal cord of rats.

Pharmacological Action and Molecular Mechanism of Glaucocalyxin B

Glaucocalyxin B(GLB)not only has many pharmacological actions such as anti-Parkinson's disease,preventing neuron injury,anti-neuritis and anti-rheumatoid arthritis,but also has good anti-tumor activity,especially with obvious therapeutic effect on cervical cancer,gastric cancer and breast cancer.In this paper,the pharmacological action and molecular mechanism of GLB are reviewed,in order to provide a theoretical basis for the development and clinical application of GLB.

MicroRNA-219 alleviates glutamate-induced neurotoxicity in cultured hippocampal neurons by targeting calmodulin-dependent protein kinase Ⅱ gamma

Septic encephalopathy is a frequent complication of sepsis,but there are few studies examining the role of micro RNAs（mi Rs） in its pathogenesis.In this study,a mi R-219 mimic was transfected into rat hippocampal neurons to model mi R-219 overexpression.A protective effect of mi R-219 was observed for glutamate-induced neurotoxicity of rat hippocampal neurons,and an underlying mechanism involving calmodulin-dependent protein kinase II γ（Ca MKIIγ） was demonstrated.mi R-219 and Ca MKIIγ m RNA expression induced by glutamate in hippocampal neurons was determined by quantitative real-time reverse transcription-polymerase chain reaction（q RT-PCR）.After neurons were transfected with mi R-219 mimic,effects on cell viability and apoptosis were measured by 3-（4,5-dimethylthiazolyl-2）-2,5-diphenyltetrazolium bromide（MTT） assay and flow cytometry.In addition,a luciferase reporter gene system was used to confirm Ca MKIIγ as a target gene of mi R-219.Western blot assay and rescue experiments were also utilized to detect Ca MKIIγ expression and further verify that mi R-219 in hippocampal neurons exerted its effect through regulation of Ca MKIIγ.MTT assay and q RT-PCR results revealed obvious decreases in cell viability and mi R-219 expression after glutamate stimulation,while Ca MKIIγ m RNA expression was increased.MTT,flow cytometry,and caspase-3 activity assays showed that mi R-219 overexpression could elevate glutamate-induced cell viability,and reduce cell apoptosis and caspase-3 activity.Moreover,luciferase Ca MKIIγ-reporter activity was remarkably decreased by co-transfection with mi R-219 mimic,and the results of a rescue experiment showed that Ca MKIIγ overexpression could reverse the biological effects of mi R-219.Collectively,these findings verify that mi R-219 expression was decreased in glutamate-induced neurons,Ca MKIIγ was a target gene of mi R-219,and mi R-219 alleviated glutamate-induced neuronal excitotoxicity by negatively controlling Ca MKIIγ expression.