Effect of Astragalus injection on expression of calmodulin after hypoxia/hypoglycemia and reoxygenation in rat hippocampal neurons

AIM: To investigate the effect of Astragalus injection on the expression of calmodulin(CaM) after hypoxia/ hypoglycemia and reoxygenation in rat hippocampal neurons.METHODS: The hippocampal neurons were cultured for 8 days and divided into 4 groups: normal control group (normal control), hypoxia/hypoglycemia and reoxygenation group (model), Astragalus injection solution group (solution control) and Astragalus injection group ( Astragalus ).The cells in all groups were treated with reoxygenation and normal medium after deprived of oxygen and glucose for 30 min except normal control group.The method of immunohistochemistry was used to measure the number of caspase-3 positive neurons.The expression of CaM at mRNA and protein levels was measured at time points of 0 h, 0.5 h, 2 h, 6 h, 24 h, 48 h, 72 h and 120 h after hypoxia/hypoglycemia and reoxygenation by RT-PCR and Western blotting, respectively.RESULTS: No difference of the parameters at all time points between model group and solution control group was found.Compared with normal control group, the numbers and the percentages of caspase-3 positive cells at all time points obviously increased in model group except at 0 h and 0.5 h (P<0.05).Compared with model group, the numbers and the percentages of caspase-3 positive cells were decreased in Astragalus injection group except at 0 h and 0.5 h (P<0.05).Compared with normal control group, the protein expression of CaM in rat hippocampal neurons at all time points obviously increased in model group (P<0.05).However, the protein expression of CaM in rat hippocampal neurons at all time points obviously decreased in Astragalus injection group as compared with model group (P<0.05).Compared with normal control group, the mRNA expression of CaM in rat hippocampal neurons at all time points obviously decreased in model group (P<0.05).The mRNA expression of CaM in rat hippocampal neurons at all time points obviously increased in Astragalus injection group as compared with model group (P<0.05).CONCLUSION: Astragalus injection inhibits the protein expression of CaM, the calcium overload and the expression of caspase-3 after hypoxia/hypoglycemia and reoxygenation, thus inhibiting hippocampal neuronal apoptosis.     

Inhibitory effect of butylphthalide on apoptosis of hippocampal neurons in Alzheimer disease rats via SIRT1/NF-κB signaling pathway

AIM: To investigate the effect of butylphthalide on apoptosis of hippocampal neurons in Alzheimer disease (AD) rats via SIRT1/NF-κB signaling pathway and its mechanism. METHODS: AD rat model was established by intragastric administration of AlCl₃ and intraperitoneal injection of D-galactose. After treated with butylphthalide at 25 mg/kg (low dose), 50 mg/kg (medium dose) and 100 mg/kg (high dose), the effects of butylphthalide on the morphology of hippocampal neurons, apoptosis rate, and the protein levels of Bcl-2, Bax, cleaved caspase-3 and the SIRT1/NF-κB signaling pathway associated proteins were determined by HE staining, flow cytometry and Western blot, respectively. After treated with SIRT1 agonist SRT1720 and inhibitor sirtinol, the role of SIRT1/NF-κB signaling pathway in hippocampal neuronal apoptosis was observed. On the basis of giving 50 mg/kg butylphthalide, sirtinol was administered, and the effect of butylphthalide on neuronal apoptosis regulated by SIRT1/NF-κB signaling pathway was evaluated. RESULTS: The morphology of hippocampal neurons in the AD rats were improved, the apoptosis rate of hippocampal neurons and the protein levels of Bax and cleaved caspase-3 were inhibited, and the protein levels of Bcl-2 and the activation of SIRT1/NF-κB signaling pathway were promoted by butylphthalide significantly (P<0.05). The protein expression of Bcl-2 and the activation of SIRT1/NF-κB signaling pathway were promoted, and the apoptosis of hippocampal neurons and the protein levels of Bax and cleaved caspase-3 were inhibited by SRT1720 remarkably (P<0.05), whereas the effect of sirtinol was contrary to that of SRT1720. After sirtinol treatment, the inhibitory effect of butylphthalide on apoptosis of hippocampal neurons, the protein levels of Bax and cleaved caspase-3, and the promotion of Bcl-2 protein expression in hippocampal neurons were markedly weakened (P<0.05). CONCLUSION: Butylphthalide inhibits the apoptosis of hippocampal neurons in the AD rats by down-regulating the protein expression of Bax and cleaved caspase-3, and up-regulating the protein expression of Bcl-2 through activating SIRT1/NF-κB signaling pathway.     

Astragalus injection inhibits the expression of JNK3 mRNA after hypoxia/hypoglycemia and reoxygenation in hippocampal neurons of rats

AIM: To investigate the effect of astragalus injection on the expression of c-jun N terminal kinase (JNK3) mRNA interrelated with apoptosis after hypoxia/hypoglycemia and reoxygenation in hippocampal neurons of rats. METHODS: The hippocampal neurons cultured for eight days were divided into 4 groups: normal control group, original astragalus injection group, hypoxia/hypoglycemia and reoxygenation group, astragalus injection group. Hypoxia/ hypoglycemia and reoxygenation group, astragalus injection group and original astragalus injection group were treated with hypoglycemia and reoxygenation after deprived of oxygen and glucose for 30 min. Methods of in situ hybridization and RT-PCR were used respectively to measure the expression of JNK3 mRNA after hypoxia/hypoglycemia and reoxygenation 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. RESULTS: In normal control group the volume of hippocampal neuronal nucleolus was accretion, cellular tuber was distinct and cytokinesis was dyed by yellow a lot. In hypoxia/hypoglycemia and reoxygenation group the hippocampal neuronal nucleolus was crimple, cellular tuber was shrinked, large number of cytokinesis was dyed by yellow and yellow granule was observed. Compared with normal control group, the numbers of JNK3 mRNA positive neuronal cells at each time point increased obviously in the hypoxia/hypoglycemia and reoxygenation group (P<0.05). The change of neuronal configuration and the numbers of JNK3 mRNA positive neuronal cells in original astragalus injection group accorded with hypoxia/ hypoglycemia and reoxygenation group (P>0.05). In astragalus injection group the hippocampal neuronal nucleolus was crimple slightly and segmental cytokinesis was dyed by yellow.Compared to hypoxia/hypoglycemia and reoxygenation group, the numbers of JNK3 mRNA positive neuronal cells at each time point were less obviously in the astragalus injection group besides 120 h (P<0.05). Compared to normal control group, the mean optic density of expression of JNK3 mRNA in hippocampal neurons of rats at each time point increased obviously in hypoxia/ hypoglycemia and reoxygenation group (P<0.05). Compared to hypoxia/hypoglycemia and reoxygenation group, the mean optic density of JNK3 mRNA expression at each time point in original astragalus injection group had no obvious change (P>0.05), however the mean optic density of JNK3 mRNA expression in hippocampal neurons of rats at each time point decreased obviously in the astragalus injection group besides 120 h (P<0.05). CONCLUSION: Astragalus injection inhibits the expression of JNK3 mRNA after hypoxia/hypoglycemia and reoxygenation, accordingly inhibits hippocampal neuronal apoptosis.     

JNK pathway promotes apoptosis of rat hippocampal neurons after cerebral ischemia and reperfusion

AIM:To investigate the effect of c-Jun N-terminal kinase(JNK) pathway on the apoptosis of hippocampal neurons after cerebral ischemia-reperfusion(IR) in SD rats. METHODS:Ninety rats were randomly divided into 5 groups:sham group, cerebral IR group,cerebral IR+JNK inhibitor(SP600125) group,cerebral IR+JNK agonist(anisomycin) group and cerebral IR+vehicle group. The brain samples were collected 24 h after reperfusion. The protein level of caspase-3 in hippocampal neurons was measured by immunohistochemical and Western blotting techniques. The mRNA expression of caspase-3 in the hippocampus was determined by real-time fluorescence quantitative PCR. The apoptosis of hippocampal neurons was detected by TUNEL staining. RESULTS:Compared with sham group, the expression of caspase-3 at mRNA and protein levels in cerebral IR group increased obviously(P<0.05). Compared with cerebral IR group, the expression of caspase-3 at mRNA and protein levels in cerebral IR+JNK inhibitor group decreased obviously(P<0.05), and those in cerebral group increased obviously(P<0.05). However, the expression of caspase-3 at mRNA and protein levels in cerebral IR+vehicle group had no obvious change(P>0.05).The apoptosis of hippocampal neurons in each group was consistent with the changes of caspase-3 at mRNA and protein levels. CONCLUSION:Activation of JNK pathway enhances caspase-3 expression in rat hippocampal neurons after cerebral IR,thus promoting the apoptosis of the neurons.     

Effect of rosuvastatin on cerebral microvascular endothelial cell injury induced by oxygen-glucose deprivation/reoxygenation

AIM: To explore the effect of rosuvastatin on the oxygen-glucose deprivation (OGD)/reoxygenation induced injury of cerebral microvascular endothelial cells (BMECs). METHODS: BMECs derived from BALB/c mice were isolated and cultured. BMECs were pretreated with rosuvastatin, followed by OGD for 3 h or 6 h and reoxygenation for 24 h. The morphological changes of BMECs were observed under light microscope. MTT assay was used to measured the cell viability, and carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) staining was used to assess the proliferation of BMECs. The protein levels of cleaved caspase-3 was observed by immunofluorescence staining. The protein levels of Bcl-2, Bax, matrix metalloproteinase (MMP) 2, MMP9, phosphorylated nuclear factor kappa B (p-NF-κB), phosphorylated P38 mitogen-activated protein kinase (p-P38) and phosphorylated c-Jun N-terminal kinase (p-JNK) were determined by Western blot. RESULTS: Rosuvastatin at 10 μmol/L improved the viability of the BMECs with OGD/reoxygenation-induced damage, and maintained the structure of BMECs. Moreover, rosuvastatin significantly prohibited the protein levels of cleaved caspase-3, MMP2, MMP9, p-NF-κB, p-P38 and p-JNK, and up-regulated the ratio of Bcl-2/Bax (P<0.05). CONCLUSION: Rosuvastatin reduces OGD/reoxygenation-induced injury of BMECs by inhibiting the expression of apoptosis-related proteins and MMPs, suggesting that rosuvastatin has potential value for the maintenance of blood-brain barrier.     

Effect of miR-25 on apoptosis of H9c2 cells induced by hypoxia/reoxygenation

AIM:To investigate the role and mechanism of microRNA-25 (miR-25) in apoptosis of H9c2 cells induced by hypoxia/reoxygenation. METHODS:The H9c2 cells with over-expression of miR-25 were treated with hypo-xia/reoxygenation. Real-time PCR was used to detect the expression of miR-25 and high mobility group box-1 (HMGB1) mRNA. Western blot was performed to examine the protein expression levels of HMGB1, Bcl-2 and cleaved caspase-3. Flow cytometry was used to analyze the proportion of apoptotic cells and the cell cycle. Dual-luciferase reporter assay was used to confirm that HMGB1 was the target gene of miR-25 in the H9c2 cells. Moreover, the H9c2 cells transfected with HMGB1-shRNA were subjected to hypoxia/reoxygenation to verify whether HMGB1 participated in the regulation of apoptosis of H9c2 cells. RESULTS:Over-expression of miR-25 significantly reduced the protein expression levels of HMGB1 and cleaved caspase-3, and increased the expression of Bcl-2 and the entrance into S phase in H9c2 cells induced by hypoxia/reoxygenation (P<0.01). The result of dual-luciferase reporter assay showed that compared with the control group, transfection with HMGB1-3' UTR-psi-CHECK2+miR-25 mimic strongly inhibited the luciferase activity (P<0.05). After the H9c2 cells transfected with HMGB1-shRNA was treated with hypoxia/reoxygenation, the expression of Bcl-2 was up-regulated, the expression of cleaved caspase-3 was down-regulated, and the cells in S phase were increased (P<0.05). CONCLUSION:miR-25 reduces apoptosis of H9c2 cells induced by hypoxia/reoxygenation, and its mechanism may be related with the inhibition of HMGB1 expression via interacting with its 3'-UTR.     

Protective effect of β-asarone on primary rat hippcampal neurons against hypoxia/hypoglycemia and reperfusion injury

AIM：To investigate the protective effect of β-asarone against hypoxia/hypoglycemia and reperfusion injury in primary rat hippocampal neurons. METHODS：Cell viability, the activity of caspase-3, the protein expression of p-JNK and Bcl-2, and the mRNA expression of Bcl-2 and caspase-3 were determined by MTT assay, spectrophoto-metry, Western blotting and real-time PCR. RESULTS：Compared with normal control group, the cell viability decreased and the activity of caspase-3 increased obviously, the expression of p-JNK protein and caspase-3 mRNA increased obviously, and the expression of Bcl-2 protein decreased obviously in model group (P<0.05). Compared with model group, different doses of β-asarone inhibited the changes of the above indexes (P<0.05). CONCLUSION：β-asarone inhibits JNK-mediated chondrosome signaling pathway, thereby attenuating the process of hippocampal neuron apoptosis after hypoxia/hypoglycemia and reperfusion.     

Ganoderma lucidum extract protects rat cerebral cortical neurons from hypoxia/reoxygenation injury in vitro

AIM: To investigate the neuroprotective effect of Ganoderma lucidum extract (GLE) in an in vitro model of primary cultured neurons with oxygen and glucose deprivation (OGD). METHODS: Neuronal injury was induced by oxygen and glucose deprivation/reoxygenation (OGD/R). The neuronal injury and viability were determined by LDH leakage and XTT assay at 0 h,3 h,6 h,12 h,24 h,48 h and 72 h after OGD/R. Neuronal apoptosis was detected by flow cytometry (FCM). The expression of apoptosis-related proteins was analyzed by Western blotting.RESULTS: The viability of the neurons increased with exposure to GLE (0.1 mg/L,1 mg/L and 10 mg/L)after OGD/R. The LDH releases were also significantly reduced. GLE significantly inhibited OGD/R-induced apoptosis of cultured rat cortical neurons in a concentration-dependent and time-dependent manner(P<0.05). GLE at concentrations of 0.1 mg/L,1 mg/L and 10 mg/L inhibited the expression of caspase-3 and caspase-8 proenzyme. Additionally,GLE at concentration of 10 mg/L suppressed the expression of caspase-9 proenzyme.CONCLUSION: Our findings provide the evidence that the GLE has neuroprotective effect on cerebral ischemia. The mechanisms are related to the inhibition of caspase-3,-8 and-9 activations. GLE may be a novel and effective reagent for treating ischemic stroke.     

Effect of HIPK2 gene on viability,apoptosis and JAK2/STAT3 signaling pathway in NRK-52E renal tubular epithelial cells induced by hypoxia and reoxygenation

AIM: To investigate the effect of homeodomain-interacting protein kinase 2 (HIPK2) on the viabi-lity, apoptosis and JAK2/STAT3 signaling pathway in NRK-52E renal tubular epithelial cells induced by hypoxia and reoxygenation (H/R). METHODS: HIPK2 small interfering RNA (siRNA) was transfected into NRK-52E cells by Lipofectamine^TM 2000, and normal control group (control group) and negative control group (HIPK2-NC group) were set up. After H/R, the cell viability was measured by CCK-8 assay, the apoptotic rate and Ca²⁺ fluorescence intensity were analyzed by flow cytometry, and the protein levels of Ki67, cleaved caspase-3, caspase-12, Bcl-2, Bax, p-JAK2 and p-STAT3 were determined by Western blot. RESULTS: Compared with control group, the protein expression of HIPK2 in the NRK-52E cells was significantly decreased after transfection with HIPK2 siRNA (P<0.05). Compared with control group, the cell viability and the protein expression of Ki67 and Bcl-2 in H/R group were also significantly decreased, and the apoptotic rate, the Ca²⁺ fluorescence intensity and the protein levels of cleaved caspase-3, caspase-12, Bax, p-JAK2 and p-STAT3 were significantly increased (P<0.05). Compared with H/R group, the cell viability and the protein expression of Ki67 and Bcl-2 in HIPK2-siRNA+H/R group were significantly increased, while the apoptotic rate, the Ca²⁺ fluorescence intensity and the protein levels of cleaved caspase-3, caspase-12, Bax, p-JAK2 and p-STAT3 were significantly decreased (P<0.05). CONCLUSION: Inhibition of HIPK2 gene expression promotes H/R-induced growth of NRK-52E renal tubular epithelial cells, and reduces the apoptosis. The mechanism is related to down-regulating the JAK2/STAT3 signaling pathway.     

Influence of hydrogen sulfide on ileal epithelial cell apoptosis in rats with intestinal ischemia-reperfusion injury

AIM: To investigate the influence of hydrogen sulfide (H₂S) on intestinal epithelial cell mitochondrial morphology and function and the expression of caspase-3, cleaved caspase-3, cytochrome C (Cyt C), Bcl-2 and Bax in rats with intestinal ischemia-reperfusion (I/R) injury. METHODS: Wistar rats (n=24) were randomly divided into 3 groups (8 in each group): sham group, I/R group and I/R+sodium hydrosulfide (NaHS) group. The animal model of intestinal I/R injury was established. The rats in I/R+NaHS group received NaHS (100 μmol/kg bolus +1 mg·kg^-1·h^-1 infusion) 10 min prior to the onset of reperfusion, whereas the rats in I/R group and sham group received equal volume of normal sodium. Ileum epithelial mitochondrial morphology and function were measured. Plasma H₂S was detected by sensitive sulfide electrode. The expression of Bcl-2 and Bax mRNA was studied by RT-PCR. The protein levels of caspase-3, cleaved caspase-3, cytochrome C (Cyt C), Bcl-2 and Bax were tested by Western blot.RESULTS: The area, volume density, maximum diameter, minimum diameter and equivalent diameter of mitochondria, and the expression of cleaved caspase-3, Cyt C and Bax in I/R group were significantly higher than those in I/R+NaHS and sham groups (P<0.01). The mitochondrial count, circumference, specific surface area, area density and population density, plasma H₂S, respiratory control rate (RCR), the ratio of P/O, R₃ , R₄, and the expression of Bcl-2 in I/R group were sharply lower than those in I/R+NaHS and sham groups (P<0.01). H₂S was negatively correlated with caspase-3, cleaved caspase-3, Cyt C and Bax (P<0.01), and was positively correlated with Bcl-2 (P<0.01). CONCLUSION: H₂S has a protective effect on mitochondrial morphology and function in rats with intestinal I/R injury by down-regulating cleaved caspase-3, Cyt C and Bax and up-regulating Bcl-2.     

Mild hypothermia protects against injury of rat hippocampal neurons induced by oxygen-glucose deprivation

AIM：To study the protective effect of mild hypothermia (31~32 °C) on rat hippocampal neurons against oxygen-glucose deprivation (OGD)-induced injury and its possible mechanisms. METHODS：An OGD experimental model of rat hippocampal neurons in vitro was established to simulate cerebral ischemic-hypoxic injury. The rat hippocampal neurons were randomly divided into 4 groups：control group, mild hypothermia group, OGD group and mild hypothermia+OGD group. The cell morphology was observed under light and electron microscopes. The neuronal apoptosis was detected by flow cytometry. The activity of caspase-3 in the cytoplasm was measured by colorimetry. RESULTS：The neuronal injury was apparent after OGD, with a great increase in apoptotic rate (P<0.01). Compared with OGD group, the morphology of neuronal injury in mild hypothermia+OGD group was attenuated, and the neuronal apoptotic rate and the activity of caspase-3 in the cytoplasm decreased. The activity of caspase-3 in the cytoplasm increased after OGD, and was positively correlated with the neuronal apoptotic rate (r=0.823, P<0.05). The activity of caspase-3 in the cytoplasm also increased after mild hypothermia and OGD, and was also positively correlated with the neuronal apoptotic rate (r=0.841, P<0.05). CONCLUSION：OGD can increase caspase-3 activity in the neuronal cytoplasm and induce neuronal apoptosis. Restraint on caspase-3 activity in the neuronal cytoplasm may be the mechanism by which mild hypothermia protects against neuronal injury induced by OGD.     

Over-expression of PGC-1α reverses mitochondrial function reduction and apoptosis in OGD/R-induced neurons

AIM: To investigate the effect of over-expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) on mitochondrial morphology and cell apoptosis in the cortical neurons with oxygen glucose deprivation/reoxygenation (OGD/R). METHODS: The whole gene sequence of PGC-1α was obtained from the cerebral cortex of C57BL/6 mice by RT-PCR and cloned into the eukaryotic expression vector pEGFP-N1. The pEGFP-N1-PGC-1α was identified by PCR, and transfected into cortical neurons. The level of PGC-1α expression was identified by Western blot. The cortical neurons transfected with pEGFP-N1 and pEGFP-N1-PGC-1α vectors were treated with OGD/R. The mitochondrial mass, reactive oxygen species (ROS) and ATP production, cell apoptosis and changes of cleaved caspase-3 were detected by MitoTracker Red staining, flow cytometry, ATP metabolic assay kit and TUNEL. RESULTS: Over-expression of PGC-1α inhibited the decrease in mitochondrial biogenesis capacity and the ROS formation of OGD/R neurons (P<0.05), enhanced the ability of ATP synthesis (P<0.01), inhibited neuronal apoptosis (P<0.01) and decreased the activation of caspase-3 (P<0.01). CONCLUSION: PGC-1α over-expression inhibits neuronal apoptosis with OGD/R treatment by promoting mitochondrial biogenesis, inhibiting the production of ROS and maintaining mitochondrial function. PGC-1α may be used as a target for the development of cerebral ischemia/reperfusion injury drugs.     

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《园艺学报》是中国园艺学会和中国农业科学院蔬菜花卉研究所主办的学术期刊,创刊于1962年,刊载有关果树、蔬菜、观赏植物、茶及药用植物等方面的学术论文、研究报告、专题文献综述、问题与讨论、新技术新品种以及园艺研究动态与信息等,适合园艺科研人员、大专院校师生及农业技术推广部门专业技术人员阅读参考。《园艺学报》是中文核心期刊,被英国《CAB文摘数据库》、美国CA化学文摘、日本CBST科学技术文献速     

Effect of CREB-shRNA on mitochondrial morphology and cell apoptosis in OGD/R-induced cortical neurons

AIM: To construct recombinant lentiviral vector with short hairpin RNA (shRNA) of CREB gene, and to investigate the effect of CREB gene silencing on mitochondrial morphology and cell apoptosis in oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cortical neurons. METHODS: Three lentiviral vectors pLentiLox3.7 (PLL) inserted shRNA fragments targeting CREB gene were co-transfected with the packaging plasmids psPAX2 and pMD2.G to the 293T cells, and the virus particles, which was infected with the primary cortical neurons, was encapsulated. The protein expression of CREB was detected by Western blot. The mitochondrial morphology, cell apoptosis and the expression of Bcl-2 and Bax were evaluated by the methods of MitoTracker red, TUNEL and Western blot in OGD/R induced cortical neurons after CREB gene silencing. RESULTS: The pLL-CREB-shRNA1 was the most effective shRNA, which inhibited 80% CREB gene expression in the cortical neurons. The mitochondrial was appeared dot and fragment morphology in OGD/R induced cortical neurons with transfected pLL-CREB-shRNA1 plasmid. In addition, the expression of Bcl-2 was decreased, the expression of Bax, and the apoptosis of the neurons were increased by tranfected with pLL-CREB-shRNA1. CONCLUSION: CREB shRNA recombinant lentiviral vector specifically inhibits the expression of CREB gene. CREB gene silencing promotes the cell apoptosis and mitochondrial morphological changes in the cortical neurons induced by OGD/R.     

Effects of Astragalus injection on neuronal apoptosis and expression of JNK3 in rat hippocampus after cerebral ischemia reperfusion

AIM:To investigate the effects of Astragalus injection on neuronal apoptosis and expression of c-Jun N-terminal kinase 3(JNK3) in the rat hippocampus after cerebral ischemia reperfusion. METHODS:The rat model of cerebral ischemia reperfusion was set up by a four-vessel occlusion method. The SD rats were randomly divided into 4 groups:sham operation group, cerebral ischemia reperfusion group(model group), cerebral ischemia reperfusion+Astragalus injection group(Astragalus injection group) and cerebral ischemia reperfusion+vehicle group(vehicle group). The rats in model group, Astragalus injection group and vehicle group after transient global cerebral ischemia(30 min) were then divided into 7 subgroups according to the reperfusion time of 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. The apoptosis of the neuron in the hippocampus was measured by the method of TUNEL staining. The expression of JNK3 at mRNA and protein levels was determined by real-time PCR and Western blotting,respectively. RESULTS:Compared with sham operation group, the number of apoptotic neurons increased in model group(P<0.05). Compared with model group, the number of apoptotic neurons decreased obviously in Astragalus injection group(P<0.05). Compared with sham operation group, the expression of JNK3 at mRNA and protein levels in the hippocampus increased obviously in model group at all time points except 120 h(P<0.05). Compared with model group, the expression of JNK3 at mRNA and protein levels in the hippocampus decreased obviously in Astragalus injection group at all time points except 120 h(P<0.05). CONCLUSION:Astragalus injection decreases neuronal apoptosis in rat hippocampus after cerebral ischemia reperfusion by inhibiting the expression of JNK3 at mRNA and protein levels.     

Effects of Homer1a over-expression on apoptosis and AMPK protein expression in mechanically injured neurons

AIM:To investigate the effects of Homer1a over-expression on the apoptosis and AMP-activated protein kinase (AMPK) protein expression in mechanically injured neurons. METHODS:The rat cortical neurons were isolated and cultured in vitro, and then ramdomly divided into control group, model group, empty vector group, and Exp-Homer1a group. Neuron models with mechanical injury were constructed and infected with the Homer1a over-expression vector. The mRNA expression of Homer1a was detected by qPCR. The cell viability in each group was detected by MTT assay. The activity of lactate dehydrogenase (LDH) in the supernatant of each group was measured by LDH test kit. The apoptosis level was analyzed by flow cytometry. The protein levels of Hormer1a, cleaved caspase-3, Bax, Bcl-2, p-AMPKα and AMPKα were determined by Western blot. RESULTS:Compared with control group, the viability of mechanically injured neurons was significantly decreased, the LDH activity in the supernatant and neuronal apoptotic rate were significantly increased (P<0.05), and Homer1a expression at mRNA and protein levels was significantly increased (P<0.05). Compared with model group, the LDH activity in the supernatant and neuronal apoptotic rate in Exp-Homer1a group were significantly decreased, the protein levels of cleaved caspase-3 and Bax were significantly decreased (P<0.05), and the protein levels of Bcl-2 and p-AMPKα were significantly increased (P<0.05). CONCLUSION:Over-expression of Homer1a may increase the viability of mechanically injured neurons and inhibit their apoptosis by promoting the activation of AMPKα phosphorylation.     

Astragalus injection inhibits expression of Apaf-1 in rat hippocampus after cerebral ischemia and reperfusion

AIM: To investigate the effect of Astragalus injection on the expression of apoptotic protease-activating factor 1 (Apaf-1) in the hippocampus of global cerebral ische-mia-reperfusion rats. METHODS: Male SD rats were randomly divided into 4 groups with 30 each: sham operation group, cerebral ischemia-reperfusion group, cerebral ischemia-reperfusion+Astragalus injection group, and cerebral ischemia-reperfusion+vehicle group. The global cerebral ischemia-reperfusion model of the rats was established by 4-vessel occlusion. The rats in cerebral ischemia-reperfusion group, cerebral ischemia-reperfusion+Astragalus injection group and cerebral ischemia-reperfusion+vehicle group were further divided into 7 subsets, according to the reperfusion time of 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. After reperfusion, the brains were removed at the corresponding time points. The protein expression of Apaf-1 in hippocampal neurons was detected by immunohistochemistry and Western blotting. The mRNA expression of Apaf-1 was observed by RT-PCR. RESULTS: Compared with sham operation group, the expression of Apaf-1 at mRNA and protein levels at all time points except 0 h and 120 h increased obviously in cerebral ischemia-reperfusion group (P<0.05). Compared with cerebral ischemia-reperfusion group, the expression of Apaf-1 at mRNA and protein levels at all time points except 0 h and 120 h decreased obviously in cerebral ischemia-reperfusion+Astragalus injection group (P<0.05). However, those in cerebral ischemia-reperfusion+vehicle group had no obvious change (P>0.05). CONCLUSION: Astragalus injection inhibits the expression of Apaf-1 at mRNA and protein levels in hippocampus of global cerebral ischemia-reperfusion rats, thus inhibiting the apoptosis of hippocampal neurons.     

Resveratrol modulates SDF-1/CXCR4 signaling to inhibit hypoxia-ischemia-induced apoptosis of neurons from the brain of newborn rats

AIM:To investigate the effect of resveratrol (RSV) on apoptosis and stromal cell-derived factor-1 (SDF-1)/CXC chemokine receptor 4 (CXCR4) pathway in hypoxia-ischemia-induced neurons from the brain of newborn rats and its mechanism. METHODS:The cortex neurons from the brain of newborn rats were given oxygen-glucose deprivation (OGD) treatment to mimic neonatal hypoxic-ischemic encephalopathy (HIE). The cortex neurons were randomly divided into 4 groups:control group, HIE model group, HIE+RSV-low (10 μmol/L) group, and HIE+RSV-high (50 μmol/L) group. After OGD treatment for 2 h, the neurons were cultured with indicated dose of RSV for 24 h. The apoptosis was analyzed by flow cytometry. Western blot was used to determine the levels of apoptosis-related proteins, SDF-1 and CXCR4. Real-time PCR was used to detect the mRNA expression of SDF-1 and CXCR4. Additionally, to explore the effects of RSV on cell apoptosis and apoptosis-related proteins after the suppression of SDF-1/CXCR4 signaling, a CXCR4 antagonist AMD3100, and RSV were used to co-treat OGD-injured neurons for 24 h. RESULTS:RSV alleviated OGD-induced neuronal apoptosis, down-regulated cleaved caspase-3 and cytochrome C levels, and up-regulated the ratio of Bcl-2/Bax. Compared with the control group, OGD treatment increased the expression of SDF-1 and CXCR4 (P<0.05). Compared with the HIE model group, RSV further up-regulated the expression of SDF-1 and CXCR4 (P<0.05). AMD3100 reversed the effects of RSV on OGD-induced cell apoptosis. CONCLUSION:RSV suppresses hypoxia-ischemia-induced apoptosis of neurons from the brain of newborn rats via up-regulating SDF-1/CXCR4 signaling pathway.