亲环素A对Aβ25-35诱导PC12细胞凋亡的影响及机制研究

目的 探讨亲环素A(CyPA)对Aβ25-35诱导的PC12细胞凋亡影响及可能的作用机制.方法 将PC12细胞分为正常对照组(0 μmol/L Aβ25-35)、Aβ25-35诱导组(10 μmol/L Aβ25-35)和药物保护组(0.1、1、10、100 nmol/L CyPA+10 μmoi/Lβ25-35),药物保护组采用相应浓度CyPA预处理PC12细胞30 min,再加入Aβ25-35继续培养.MTT法分析细胞存活率,Hoechst33258染色法检测细胞凋亡,RT-PCR检测Bcl-2和Bax mRNA表达,Western blotting检测Bcl-2和Bax蛋白表达.结果 1、10和100 nmol/L CyPA可提高细胞的存活率,减少Aβ25-35引起的细胞凋亡,增加Bcl-2mRNA表达以及Bcl-2蛋白表达,降低Bax mRNA表达以及Bax蛋白表达,与Aβ25-35诱导组比较差异有统计学意义(P<0.05),且CyPA剂量越高效果越明显.结论 CyPA可剂量依赖性对抗Aβ25-35对PC12细胞的毒性作用,减少细胞凋亡,其机制与上调抗凋亡基因Bcl-2表达和下调凋亡基因Bax表达有关.

Abstract：

Objective To explore the effect of cyclophilin A (CyPA) on apoptosis of PC 12 cells induced by Aβ25-35 and its potential mechanism. Methods PC 12 cells were divided into normal control group (0 μmol/L Aβ25-35), Aβ25-35 inducement group (10 μmol/L Aβ25-35) and drug protection groups (0.1, 1,10 and 100 nmol/L CyPA+10 μmol/L Aβ25-35). Cells in the drug protection groups were pretreated by CyPA of different concentrations for 30 min, and then co-cultured with Aβ25-35 We evaluated the survival rate of PC12 cells with MTT assay, analyzed the apoptosis of PC12 cells with Hoechst33258 staining, and detected the mRNA expressions of Bcl-2 and Bax with PT-PCR and the protein levels of Bcl-2 and Bax with Western blotting. Results Cells pretreated wth CyPA of 1, 10 and 100 nmol/L enjoyed an obvious elevation of survival rate of PC 12 cells, a significant reduction of apoptosis induced by Aβ25-35,an obvious increase of mRNA expression of Bcl-2 and protein level of Bcl-2, and a statistical decrease of mRNA expression of Bax and protein level of Bax as compared with those cells of the Aβ25-35 inducement group (P<0.05);and these effects were dose-dependent. Conclusion CyPA could resist the toxic role of Aβ25-35 on PC 12 cells and reduce the apoptosis in a dose-dependent manner by up-regulation of anti-apoptosis gene Bcl-2 and down-regulation of apoptosis gene Bax.     

BDNF对β-淀粉样蛋白诱导细胞损伤的保护作用

目的 探讨脑源性神经生长因子(brain-derived neurotrophic factor,BDNF)对凝聚态β-淀粉样蛋白25-35片断(Aβ25-35)诱导细胞凋亡的影响.方法 采用PC12细胞作为研究对象,将培养的细胞随机分为20 μmol/L Aβ25-35处理不同时间组(0、30 min以及1、3、6、12、48 h)、20 μmol/L Aβ25-35+不同浓度的BDNF(20、50、100 ng/mL)处理组、单独Trk B受体抑制剂K252α(200 nmol/L)处理组、20 μmol/L Aβ25-35+50 ng/mL BDNF处理组、K252α(200 nmol/L)+20 μmol/L Aβ25-35+50 ng/mL BDNF处理组.采用MTT法观察不同处理组PC12细胞的活力,采用Western blot法检测不同处理组PC12细胞Cleaved caspase-3表达的变化.结果 20 μmol/L的Aβ25-35作用不同时间后细胞活力均明显下降,且呈一定的时间依赖趋势(P<0.05);不同浓度的BDNF(20、50、100 ng/mL)预处理后均可明显抑制 20 μmol/L的Aβ25-35诱导的细胞活力下降(P<0.05); 20 μmol/L的Aβ25-35可诱导PC12细胞Cleaved caspase-3表达增高(P<0.05),50 ng/mL的BDNF可明显抑制20 μmol/L的Aβ25-35诱导的Cleaved caspase-3表达的增高(P<0.05),Trk B受体抑制剂K252α(200 nmol/L)预处理后,50 ng/mL的BDNF对20 μmol/L的Aβ25-35诱导的Cleaved caspase-3表达增高的抑制作用明显减弱(P<0.05).结论 BDNF对Aβ25-35诱导的细胞损伤具有保护作用,且其保护作用是通过与其特异性受体Trk B结合而实现.     

Cyclophilin A affects Bcl-2 and Bax expression following beta-amyloid fragment 25-35-induced injury to PC12 cells★

BACKGROUND: Cyclophilin A can protect neurons against oxidative stress. OBJECTIVE: To investigate the effect of cyclophilin A on Bcl-2 and Bax protein expression in pheochro-mocytoma (PC12) cells treated with beta-amyloid fragment 25-35 (Aβ25-35), and to verify the protection pathway of cyclophilin A. DESIGN, TIME AND SETTING: The initial experiment was performed at the Laboratory of Department of Neurology, First Clinical College, China Medical University from November 2006 to July 2007. MATERIALS: PC12 cells were cultured at the Cell Center of Peking Union Medical College. Aβ25-35 (Sigma, USA), antibodies of Bcl-2 and Bax (Wuhan Boster, China), and recombinant human cyclophilin A (Biomol, USA) were used in this study. METHODS: PC12 cells were divided into three groups. Cells in the control group were incubated in culture medium. Cells in the Aβ25-35 injury group were incubated in medium containing a final concentration of 10 μmol/L of Aβ25-35. Cells in the cyclophilin A group were incubated in medium containing a final con-centration of 10 nmol/L of cyclophilin A for 30 minutes, and then treated with 10 μmol/L Aβ25-35. MAIN OUTCOME MEASURES: After 24 hours of culture, immunohistochemistry was used to detect Bcl-2 and Bax expression in PC12 cells. Annexin-V flow cytometry was employed to measure the apoptosis rate of PC12 cells. The MTT method was applied to examine the survival rate of PC12 cells. RESULTS: Bcl-2 expression decreased, whereas Bax expression increased in PC12 cells treated with Aβ25-35 (t = 2.277, 5.957, P < 0.05). However, in PC12 cells treated with Aβ25-35 and cyclophilin A, Bcl-2 expression increased and Bax expression decreased (t = 4.497, 2.531, P < 0.05). The survival rate of PC12 cells significantly decreased and the apoptosis rate increased (t=8.509, 22.886, P < 0.05) following Aβ25-35 treatment. Cyclophilin A enhanced the survival rate of PC12 cells to Aβ25-35-induced apoptosis (t = 4.895, 10.042, P < 0.05). CONCLUSION: Cyclophilin A can increase Bcl-2 expression and decrease Bax expression in PC12 cells treated with Aβ25-35, which indicates that cyclophilin A has a protective effect on Aβ25-35-induced injury to PC12 cells. Key Words: cyclophilin A; pheochromocytoma (PC12) cells; β-amyloid fragment 25-35; Bcl-2; Bax     

Cyclophilin A affects Bcl-2 and Bax expression following beta-amyloid fragment 25-35-induced injury to PC12 cells★

BACKGROUND: Cyclophilin A can protect neurons against oxidative stress.OBJECTIVE: To investigate the effect of cyclophilin A on Bcl-2 and Bax protein expression in pheochromocytoma (PCI2) cells treated with beta-amyloid fragment 25-35 (A β25-35), and to verify the protection pathway ofcyclophilin A.DESIGN, TIME AND SETTING: The initial experiment was performed at the Laboratory of Department of Neurology, First Clinical College, China Medical University from November 2006 to July 2007.MATERIALS: PCI2 cells were cultured at the Cell Center of Peking Union Medical College. A β25-35 (Sigma, USA), antibodies of Bcl-2 and Bax (Wuhan Boster, China), and recombinant human cyclophilin A (Biomol, USA) were used in this study.METHODS: PC12 cells were divided into three groups. Cells in the control group were incubated in culture medium. Cells in the Aβ25-35 injury group were incubated in medium containing a final concentration of 10 μ mol/L of Aβ25-35. Cells in the cyclophilin A group were incubated in medium containing a final concentration of 10 nmol/L of cyclophilin A for 30 minutes, and then treated with 10 μmol/L Aβ25-35. MAIN OUTCOME MEASURES: After 24 hours of culture, immunohistochemistry was used to detect Bcl-2 and Bax expression in PC12 cells. Annexin-V flow cytometry was employed to measure the apoptosis rate of PC12 cells. The MTT method was applied to examine the survival rate of PC12 cells.RESULTS: Bcl-2 expression decreased, whereas Bax expression increased in PCI2 cells treated with Aβ25-35 (t = 2.277, 5.957, P<0.05). However, in PC12 cells treated with Aβ25-35 and cyclophilin A, Bcl-2 expression increased and Bax expression decreased (t = 4.497, 2.531, P < 0.05). The survival rate of PC12 cells significantly decreased and the apoptosis rate increased (t=8.509, 22.886, P < 0.05) following Aβ25-35 treatment. Cyclophilin A enhanced the survival rate of PC12 cells to Aβ25-35-induced apoptosis (t = 4.895, 10.042, P< 0.05).CONCLUSION: Cyclophilin A can increase Bcl-2 expression and decrease Bax expression in PC12 cells treated with Aβ25-35, which indicates that cyclophilin A has a protective effect on Aβ25-35-induced injury to PC12 cells.     

Brain-derived neurotrophic factor protects PC12 cells from beta-amyloid-induced neurotoxicity through the tropomyosin-related kinase B receptor pathway

The present study utilized beta amyloid (Aβ)-induced cell apoptosis in PC12 cells as a cell model of Alzheimer’s disease to investigate the interaction between brain-derived neurotrophic factor (BDNF) and the tropomyosin-related kinase B receptor. Results showed that Aβ(25-35) can reduce survival of PC12 cells and increase cleaved caspase-3 expression in PC12 cells. However, BDNF inhibited Aβ(25-35)-induced cytotoxicity and cleaved casapase-3 expression. Interestingly, pretreatment with the tropomyosin-related kinase receptor inhibitor K252a for 20 minutes prior to BDNF blocked the neuroprotective effect of BDNF on PC12 cells.     

Hydrogen sulfide inhibits beta-amyloid peptide-induced apoptosis in PC12 cells and the underlying mechanisms*★

BACKGROUND: Studies have demonstrated that hydrogen sulfide (H2S) levels are 55% lower in brains of Alzheimer’s disease (AD) patients than in age-matched normal individuals, which suggests that H2S might be involved in some aspects of AD pathogenesis. OBJECTIVE: To observe the protective mechanisms of varied concentrations of H2S against β-amyloid-peptide (Aβ) induced apoptosis in pheochromoytoma (PC12) cells, and to analyze the pathway of action. DESIGN, TIME AND SETTING: A controlled, observational, in vitro experiment was performed at Neurophysiology Laboratory in Zhongshan Medical School, Sun Yat-sen University between July 2006 and May 2007. MATERIALS: PC12 cells were provided by the Animal Experimental Center of Medical School of Sun Yat-sen University. Glybenclamide, rhodamine123, and dihydrorhodamine123 were purchased from Sigma (USA). METHODS: PC12 cells were incubated at 37 ℃ in a 5% CO2-enriched incubator with RPMI-1640 medium, supplemented with 5% horse-serum and 10% fetal bovine serum. Cells in logarithmic growth curves received different treatment: The PC12 cells were maintains at 37 ℃ with the original medium, then incubated in Aβ25-35, sodium hydrosulfide (NaHS), glybenclamide, NaHS+ Aβ25-35, or pretreated with glybenclamide 30 minutes prior to administration of and Aβ25-35, respectively. MAIN OUTCOME MEASURES: (1) The survival rate of PC12 cells was detected by MTT assay and Hoechst staining. (2) The apoptosis rate of PC12 cells was detected utilizing flow cytometry with propidium iodide staining, and morphological changes of apoptotic cells were observed. (3) The mitochondrial membrane potential was detected by Rhodamine123-combined flow cytometry. (4) The intracellular reactive oxygen species content was detected by dihydrorhodamine123-combined flow cytometry. RESULTS: Aβ25-35 induced significantly decreased viability and increased percentage of apoptosis in PC12 cells, as well as dissipated mitochondrial membrane potential expression and an overproduction of reactive oxygen species. When PC12 cells were co-treated with NaHS and Aβ25-35, the decreased cell viability induced by 20 μmol/L Aβ25-35 was concentration-dependently blocked by NaHS (50, 100, and 200 μmol/L). NaHS (100 μmol/L) obviously reduced the percentage of apoptotic PC12 cells induced by 20 μmol/L Aβ25-35. In addition, 100 μmol/L NaHS inhibited mitochondrial membrane potential dissipation and reactive oxygen species overproduction. When the ATP-sensitive K channel (KATP) inhibitor, glybenclamide, was administered 30 minutes prior to NaHS and Aβ25-35 treatment, the NaHS-dependent cellular protection was partly blocked. This resulted in reduced PC12 cell viability and increased the percentage of apoptosis, as well as significantly blocked mitochondrial membrane potential preservation and inhibited reactive oxygen species overproduction due to NaHS treatment. CONCLUSION: NaHS protected PC12 cells against Aβ25-35-induced damage. NaHS-dependent cellular protection was associated with mitochondrial membrane potential preservation and inhibition of reactive oxygen species overproduction. The KATP channel inhibitor, glybenclamide, significantly blocked the cellular protective effects of NaHS, indicating that KATP channel activation plays an important role in NaHS-induced protection of PC12 cells to Aβ25-35-induced damage. Key Words: apoptosis; β-amyloid peptide; cytoprotection; hydrogen sulfide; mitochondrial membrane potential; reactive oxygen species     

Role of Notch-1 signaling pathway in PC12 cell apoptosis induced by amyloid beta-peptide(25–35)

Recent studies have demonstrated that Notch-1 expression is increased in the hippocampus of Alzheimer's disease patients. We speculate that Notch-1 signaling may be involved in PC12 cell apoptosis induced by amyloid beta-peptide(25–35)(Aβ25–35). In the present study, PC12 cells were cultured with different doses(0, 0.1, 1.0, 10 and 100 nmol/L) of N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester, a Notch-1 signaling pathway inhibitor, for 30 minutes. Then cultured cells were induced with Aβ25–35 for 48 hours. Pretreatment of PC12 cells with high doses of N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester( 10 nmol/L) prolonged the survival of PC12 cells after Aβ25–35 induction, decreased the expression of apoptosis-related proteins caspase-3,-8,-9, increased the activity of oxidative stress-related superoxide dismutase and catalase, inhibited the production of active oxygen, and reduced nuclear factor kappa B expression. This study indicates that the Notch-1 signaling pathway plays a pivotal role in Aβ25–35-induced PC12 apoptosis.     

Brain-derived neurotrophic factor prevents beta- amyloid-induced apoptosis of pheochromocytoma cells by regulating Bax/Bcl-2 expression

Brain-derived neurotrophic factor was utilized in the present study to treat cell injury models induced by aggregated β-amyloid(25-35).Methylthiazolyldiphenyl-tetrazolium bromide assay and western blot analysis showed that brain-derived neurotrophic factor provided neuroprotection against cellular apoptosis by suppressing the decline in β-amyloid(25-35)-induced cell activity and the increasing ratio of Bax/Bcl-2.After treating pheochromocytoma cells with tyrosine kinase receptor B receptor inhibitor K252a,brain-derived neurotrophic factor reverses the above-mentioned changes.The experimental findings suggested that brain-derived neurotrophic factor prevented β-amyloid peptide-induced cellular apoptosis by modulating Bax/Bcl-2 expression,and this effect was associated with binding to the specific tyrosine kinase receptor B receptor.     

Hydrogen sulfide inhibits beta-amyloid peptide-induced apoptosis in PC12 cells and the underlying mechanisms*★

BACKGROUND: Studies have demonstrated that hydrogen sulfide (H2S) levels are 55% lower in brains of Alzheimer's disease (AD) patients than in age-matched normal individuals, which suggests that H2S might be involved in some aspects of AD pathogenesis.OBJECTIVE: To observe the protective mechanisms of varied concentrations of H2S against β -amyloid-peptide (A β) induced apoptosis in pheochromoytoma (PC12) cells, and to analyze the pathway of action.DESIGN, TIME AND SETTING: A controlled, observational, in vitro experiment was performed at Nenrophysiology Laboratory in Zhougshan Medical School, Sun Yat-sen University between July 2006 and May 2007.MATERIALS: PC12 cells were provided by the Animal Experimental Center of Medical School of Sun Yat-sen University. Glybenclamide, rhodamine123, and dihydrorhodamine123 were purchased from Sigma (USA).METHODS: PCI2 cells were incubated at 37℃ in a 5% CO2-enriched incubator with RPMI-1640 medium, supplemented with 5% horse-serum and 10% fetal bovine serum. Cells in logarithmic growth curves received different treatment: The PC12 cells were maintains at 37℃ with the original medium, then incubated in A β 25-35, sodium hydrosulfide (NariS), glybenclamide, NailS A β 25-35, or pretreated with glybenelamide 30 minutes prior to administration of and A β 25-35, respectively. MAIN OUTCOME MEASURES: (1) The survival rate of PC12 cells was detected by MTT assay and Hoechst staining. (2) The apoptosis rate of PC12 cells was detected utilizing flow cytometry with propidium iodide staining, and morphological changes of apoptotic cells were observed. (3) The mitochondrial membrane potential was detected by Rhodamine 123-combined flow cytometry. (4) The intracellular reactive oxygen species content was detected by dihydrorhodamine123-combined flow cytometry. RESULTS: A β 25-35 induced significantly decreased viability and increased percentage of apoptosis in PC 12 cells, as well as dissipated mitochondrial membrane potential expression and an overproduction of reactive oxygen species. When PC12 cells were co-treated with Nails and A β 25-35, the decreased cell viability induced by 20 μ mol/L A β 25-35 was concentration-dependently blocked by NariS (50, 100, and 200 p mol/L). NaHS (100 μ mol/L) obviously reduced the percentage of apoptotic PCI2 cells induced by 20 μ mol/L A β 25-35. In addition, 100 μ mol/L NariS inhibited mitochondrial membrane potential dissipation and reactive oxygen species overproduction. When the ATP-sensitive K channel (KATP) inhibitor, glybenclamide, was administered 30 minutes prior to NailS and A β 25-35 treatment, the NariS-dependent cellular protection was partly blocked. This resulted in reduced PC12 cell viability and increased the percentage of apoptosis, as well as significantly blocked mitochondrial membrane potential preservation and inhibited reactive oxygen species overproduction due to Naris treatment.CONCLUSION: NaHS protected PC 12 cells against A β 25-35-induced damage. NariS-dependent cellular protection was associated with mitochondrial membrane potential preservation and inhibition of reactive oxygen species overproduction. The KATP channel inhibitor, glybenclamide, significantly blocked the cellular protective effects of NariS, indicating that KATP channel activation plays an important role in NariS-induced protection of PC 12 cells to A β 25 35-induced damage.     

Gengnianchun recipe inhibits apoptosis of pheochromocytoma cells from beta-amyloid 25-35 insult, better than monotherapies and their compounds

This study aims to determine and compare the protective effects of Gengnianchun recipe drug serum and compounds of its representative drug monotherapies against sympathetic nerve pheochromocytoma cell line PC12 cells damaged by beta-amyloid 25-35 at the cellular apoptosis and related signal pathway levels. PC12 cells cultured with medicated rat serum showed enhanced cell viability and reduced cellular apoptosis rates compared with those of monotherapies and their compounds. Furthermore, Gengnianchun recipe up-regulated expressions of anti-apoptotic protein Bcl-2, estrogen receptor-beta and phosphorylated extracellular-signal-regulated kinase 1/2; and down-regulated expressions of pro-apoptotic proteins Bax and caspase-3. Gengnianchun recipe was superior to representative drug monotherapies, such as paeoniflorin, berberine, timosaponin A-III, icariine and their compounds in protecting PC12 cells. Mitogen-activated protein kinase blocker and estrogen receptor antagonist were found to reverse the above effects of Gengnianchun recipe. The experimental findings indicate that, Gengnianchun recipe protects PC12 cells from beta-amyloid 25-35 insult; its inhibitory effect on apoptosis may be achieved through the mitogen-activated protein kinase and estrogen receptor pathways.     

Cyanidin suppresses amyloid beta-induced neurotoxicity by inhibiting reactive oxygen species-mediated DNA damage and apoptosis in PC12 cells

Amyloid beta(Aβ)-induced oxidative stress is a major pathologic hallmark of Alzheimer's disease. Cyanidin, a natural flavonoid compound, is neuroprotective against oxidative damage-mediated degeneration. However, its molecular mechanism remains unclear. Here, we investigated the effects of cyanidin pretreatment against Aβ-induced neurotoxicity in PC12 cells, and explored the underlying mechanisms. Cyanidin pretreatment significantly attenuated Aβ-induced cell mortality and morphological changes in PC12 cells. Mechanistically, cyanidin effectively blocked apoptosis induced by Aβ, by restoring the mitochondrial membrane potential via upregulation of Bcl-2 protein expression. Moreover, cyanidin markedly protected PC12 cells from Aβ-induced DNA damage by blocking reactive oxide species and superoxide accumulation. These results provide evidence that cyanidin suppresses Aβ-induced cytotoxicity, by preventing oxidative damage mediated by reactive oxide species, which in turn inhibits mitochondrial apoptosis. Our study demonstrates the therapeutic potential of cyanidin in the prevention of oxidative stress-mediated Aβ neurotoxicity.     

Protective effects of Ginkgo biloba extract on 6-hydroxydopamine-induced apoptosis in PC12 cells

The present study analyzed the protective effects of Ginkgo biloba extract against 6-hydroxydopamine-induced PC12 cell apoptosis in a model of Parkinson’s disease. The results showed that Ginkgo biloba extract had a potent cytoprotective action and inhibited apoptosis of PC12 cells induced by 6-hydroxydopamine. Ginkgo biloba extract decreased the ratio of Bax to Bcl-2 and markedly inhibited the activation of p53 and caspase-3. These experimental findings indicate that Ginkgo biloba extract may significantly reduce the effects of oxidative stress induced by 6-hydroxydopamine in PC12 cells and suppress cell apoptosis. The potential effects of Ginkgo biloba extract might be greater than those of levodopa in the treatment of Parkinson’s disease.     

Acupuncture at Baihui and Dazhui reduces brain cell apoptosis in heroin readdicts简

Acupuncture at Baihui （GV20） and Dazhui （GV14） reduces neuronal loss and attenuates ultra- structural damage in cerebral ischemic rats. However, whether acupuncture can treat addiction and prevent readdiction through changes to brain cell ultrastructure remains unknown. In this study, cell apoptosis was observed in the hippocampus and frontal lobe of heroin readdicted rats by electron microscopy. Immunohistochemical staining displayed a reduction in Bcl-2 ex- pression and an increase in Bax expression in the hippocampus and frontal lobe. After rats were given acupuncture at Baihui and Dazhui, the pathological damage in the hippocampus and frontal lobe was significantly reduced, Bcl-2 expression was upregulated and Bax expression was downregulated. Acupuncture exerted a similar effect with methadone, a commonly used drug for clinical treatment of drug addiction. Experimental findings suggest that acupuncture at Dazhui and Baihui can prevent brain cell apoptosis in heroin readdicted rats.     

Inhibition of microRNA-29b suppresses oxidative stress and reduces apoptosis in ischemic stroke

MicroRNAs(miRNAs) regulate protein expression by antagonizing the translation of mRNAs and are effective regulators of normal nervous system development, function, and disease. Micro RNA-29 b(mi R-29 b) plays a broad and critical role in brain homeostasis. In this study, we tested the function of mi R-29 b in animal and cell models by inhibiting mi R-29 b expression. Mouse models of middle cerebral artery occlusion were established using the modified Zea-Longa suture method. Prior to modeling, 50 nmol/kg mi R-29 b antagomir was injected via the tail vein. Mi R-29 b expression was found to be abnormally increased in ischemic brain tissue. The inhibition of mi R-29 b expression decreased the neurological function score and reduced the cerebral infarction volume and cell apoptosis. In addition, the inhibition of mi R-29 b significantly decreased the malondialdehyde level, increased superoxide dismutase activity, and Bcl-2 expression, and inhibited Bax and Caspase3 expression. PC12 cells were treated with glutamate for 12 hours to establish in vitro cell models of ischemic stroke and then treated with the mi R-29 antagomir for 48 hours. The results revealed that mi R-29 b inhibition in PC12 cells increased Bcl-2 expression and inhibited cell apoptosis and oxidative damage. These findings suggest that the inhibition of mi R-29 b inhibits oxidative stress and cell apoptosis in ischemic stroke, producing therapeutic effects in ischemic stroke. This study was approved by the Laboratory Animal Care and Use Committee of the First Affiliated Hospital of Zhengzhou University(approval No. 201709276 S) on September 27, 2017.     

缺氧复氧大鼠海马星形胶质细胞凋亡及Bcl-2和Bax蛋白表达的时间进程变化及异丙酚干预效应

BACKGROUND： Cerebral hippocampal astrocytes are more sensitive.to ischemic injury than neurons. Hypoxic-ischemic brain injury induces profound astrocyte apoptosis, and propofol may protect against astrocyte apoptosis.
OBJECTIVE： To verify the protective effects of propofol against astrocyte apoptosis and to investigate anti-apoptotic Bcl-2 and pro-apoptotic Bax expression in primary cultures of rat hippocampal astrocytes exposed to hypoxia-reoxygenation for different periods of time following propofol treatment.
DESIGN, TIME, AND SETTING： In vitro neural immunocytochemistry was performed at the Central Laboratory of Yunyang Medical College between September 2007 and March 2008.
MATERIALS： A total of 30 Wistar rats, aged 1-3 days, wJth equal numbers of males and females, were included for isolation and culture of .hippocampal astrocytes.
METHODS： Hippocampal astrocytes were purified and cultured for 3 weeks and treated with four culture conditions： 50 μL Hank＇s solution （normal control）; 0.2 mL/L Intralipid; 50 μL Hank＇s solution for 10 minutes followed by hypoxic incubation for 4 hours and normoxic incubation for 12, 24, 36, 48, 60 or 72 hours; propofol （250 μmol/L final） for 10 minutes followed by hypoxic incubation for 4 hours and normoxic incubation for 12, 24, 36, 48, 60 and 72 hours.
MAIN OUTCOME MEASURES： （1） Morphologic changes in hippocampal astrocytes. （2） Levels of astrocyte apoptosis and Bcl-2 and Bax expression.
RESULTS： Hypoxia and reoxygenation increased apoptosis over time, with Bcl-2 expression peaking at 24 hours and decreasing gradually （P 〈 0.01 ）; Bax expression peaked at 72 hours （P 〈 0.01）; the ratio of Bcl-2/Bax was 1.4, 0.8, and 0.6, respectively, at 24, 48 and 72 hours. Non-apoptotic astrocytes showed significant proliferation and swelling. Propofol treatment decreased apoptosis after hypoxia-reoxygenation （P 〈 0.01）, as well as Bct-2 and Bax expression （P 〈 0.05, P 〈 0.01）, with Bcl-2/Bax ratios of 1.6-1.8. Propofol treatmentalso blocked astrocyte proliferation and swelling. No apoptotic cells or Bcl-2/Bax expression was detected in astrocytes cultured in Hank＇s or Intralipid solution.
CONCLUSION： Propofol protects astrocytes against injury caused by hypoxia and reoxygenation via a mechanism that involves maintaining high ratios of Bcl-2/Bax.     

Scutellaria baicalensis stem-leaf total flavonoid reduces neuronal apoptosis induced by amyloid beta-peptide (25-35)

Scutellaria baicalensis stem-leaf total flavonoid might attenuate learning/memory impairment and neuronal loss in rats induced by amyloid beta-peptide. This study aimed to explore the effects of Scutellaria baicalensis stem-leaf total flavonoid on amyloid beta-peptide-induced neuronal apoptosis and the expression of apoptosis-related proteins in the rat hippocampus. Male Wistar rats were given intragastric administration of Scutellaria baicalensis stem-leaf total flavonoid, 50 or 100 mg/kg, once per day. On day 8 after administration, 10 μg amyloid beta-peptide (25-35) was injected into the bilateral hippocampus of rats to induce neuronal apoptosis. On day 20, hippocampal tissue was harvested and probed with the terminal deoxyribonucleotidyl transferase-mediated biotin-16-dUTP nick-end labeling assay. Scutellaria baicalensis stem-leaf total flavonoid at 50 and 100 mg/kg reduced neuronal apoptosis induced by amyloid beta-peptide (25-35 in the rat hippocampus. Immunohistochemistry and western blot assay revealed that expression of the pro-apoptotic protein Bax, cytochrome c and caspase-3 was significantly diminished by 50 and 100 mg/kg Scutellaria baicalensis stem-leaf total flavonoid, while expression of the anti-apoptotic protein Bcl-2 was increased. Moreover, 100 mg/kg Scutellaria baicalensis stem-leaf total flavonoid had a more dramatic effect than the lower dosage. These experimental findings indicate that Scutellaria baicalensis stem-leaf total flavonoid dose-dependently attenuates neuronal apoptosis induced by amyloid beta-peptide in the hippocampus, and it might mediate this by regulating the expression of Bax, cytochrome c, caspase-3 and Bcl-2.     

Medium-intensity acute exhaustive exercise induces neural cell apoptosis in the rat hippocampus

The present study assessed the influence of medium-intensity (treadmill at a speed of 19.3 m/min until exhaustion) and high-intensity (treadmill at a speed of 26.8 m/min until exhaustion) acute exhaustive exercise on rat hippocampal neural cell apoptosis. TUNEL staining showed significantly increased neural cell apoptosis in the hippocampal CA1 region of rats after medium- and high-intensity acute exhaustive exercise, particularly the medium-intensity acute exhaustive exercise, when compared with the control. Immunohistochemistry showed significantly increased expression of the antiapoptotic protein Bcl-2 and the proapoptotic protein Bax in the hippocampal CA1 region of rats after medium- and high-intensity acute exhaustive exercise. Additionally, the ratio of Bax to Bcl-2 increased in both exercise groups. In particular, the medium-intensity acute exhaustive exercise group had significantly higher Bax and Bcl-2 protein expression and a higher Bax/Bcl-2 ratio. These findings indicate that acute exhaustive exercise of different intensities can induce neural cell apoptosis in the hippocampus, and that medium-intensity acute exhaustive exercise results in greater damage when compared with high-intensity exercise.     

人参皂甙Rg1对去卵巢大鼠面神经核脑源性神经营养因子表达的影响：半定量分析

BACKGROUND： Estrogen is neuroprotective effects such as breast carcinoma, endometria but long-term estrogen treatment can induce side cancer, and stroke. However, phytoestrogen is neuroprotective without these side effects. OBJECTIVE： To study the effects of Ginsenoside Rgl on facial neurons and brain-derived neurotrophic factor （BDNF） expression in the facial nucleus in ovariectomized rats. DESIGN, TIME AND SETTING： The randomized, controlled animal experiments were performed at the Ultrasonic Institute, Second Affiliated Hospital, Chongqing Medical University, China, from September 2007 to September 2008. MATERIALS： Ginsenoside Rgl （Sigma, USA）, rabbit anti-rat BDNF, Bcl-2, Bax antibodies, biotin-labeled goat anti-rabbit IgG （Boster, China）, and a TUNEL kit （Roche, Germany） were used in this study. METHODS： A total of 48 adult Sprague Dawley rats undergoing ovariectomy were randomly assigned into sham operation （n = 8）, model （n = 20）, and Ginsenoside Rgl （n = 20） groups. Facial nerve damage was induced by bilateral clamping of the facial nerve trunk. The bilateral facial nerve trunk was exposed in the sham operation group, with no clamping. Rats in the Ginsenoside Rgl group were intraperitoneally injected with 10 mg/kg per day Ginsenoside Rgl; other groups received 2 mL saline, once a day, for 14 days. MAIN OUTCOME MEASURES： Morphologic changes in neurons of the facial nucleus were observed following hematoxylin-eosin staining. Neuronal apoptosis was detected by TUNEL. Changes in ultrastructure of the facial nerve fibers were observed with a transmission electron microscope. Expression of BDNF, Bcl-2, and Bax protein was quantified by semiquantitative immunohistochemistry. RESULTS： At 3-14 days following facial nerve damage, Ginsenoside Rgl increased BDNF expression and the number of regenerated nerve fibers, and produced thicker myelin sheaths （P 〈 0.05）. Ginsenoside Rgl also gradually increased Bcl-2 protein expression and decreased Bax protein expression （P 〈 0.05）. By day 7, apoptosis was observed in facial neurons, but Ginsenoside Rgl reduced the number of apoptotic neurons. Sham animals did not show any changes in BDNF, Bcl-2, or Bax expression or facial neuron morphology. CONCLUSION： Ginsenoside Rgl can substantially inhibit facial neuronal apoptosis by increasing endogenous BDNF and Bcl-2 expression and by decreasing Bax expression in ovariectomized rats after facial nerve damage.     

异丙酚预处理大鼠缺血再灌注脑皮质细胞的凋亡

The present study aimed to observe cortical expression of Bcl-2 and Bax,cysteine-dependent aspartate directed proteases-3 activity and apoptotic cell death in a rat model of middle cerebral artery occlusion pretreated with propofol.Results showed that,propofol pretreatment significantly reduced oxidative stress levels and attenuated neuronal apoptosis in the cortex of rats.Propofol pretreatment upregulated Bcl-2 expression,and downregulated Bax expression and cysteine-dependent aspartate directed proteases-3 activity.These findings indicate that propofol pretreatment inhibits cell apoptosis during focal cerebral ischemia/reperfusion injury.This neuroprotective effect is most likely achieved through the Bcl-2/Bax/cysteine-dependent aspartate directed proteases-3 pathway.     

灵芝多糖对Aβ25-35诱导的PC12细胞损伤的保护性研究

目的观察灵芝多糖(GLP)对β-淀粉样蛋白(Aβ25-35)诱导的PC12细胞损伤的保护作用。方法将Aβ25-35或(和)不同浓度的GLP加入体外培养的PC12细胞中,用MTT检测PC12细胞活力的变化;以DCFH-DA来检测细胞内活性氧(ROS)水平的改变;通过Western Blotting来检测Bcl-2和Bax的表达水平。结果 Aβ25-35处理36h后的PC12细胞存活率仅为对照的60.7%,细胞内ROS水平上升到原来的222.7%,同时Bcl-2/Bax比值下降,为对照组的60.0%。经不同浓度的GLP预处理后,细胞存活率均显著提高,分别能达到69.7%,80.7%和88.3%(P<0.01);10g/ml GLP预处理PC12细胞24h后,细胞内ROS水平下降至正常组的160.6%,Bcl-2/Bax比值升高到93.6%,P值均<0.01。结论 GLP对Aβ25-35诱导的PC12细胞损伤有保护作用。