脑源性神经营养因子对H2O2诱导人动脉平滑肌细胞凋亡的作用

目的 研究脑源性神经营养因子（BDNF）对过氧化氢（H2O2）诱导人动脉平滑肌细胞（SMC）凋亡的作用。方法 BDNF基因经脂质介导转染SMC,I型胶原基因调节元件（COLIAI）驱动该基因在SMC中异位表达,用MTT法检测细胞增殖,吖啶橙（AO）荧光染色观察细胞形态学变化,流式细胞仪检测细胞凋亡率,琼脂糖电泳检测DNA图谱。结果 100－800μmol/L浓度的H2O2明显抑制SMC增殖,200μmol/L H2O2作用24h后,可见典型的细胞凋亡形态学及生物化学改变胞浆固缩,核染色质断裂,DNA电泳呈梯形条带,经BDNF基因修饰的SMC则未显示上述改变。结论 H2O2能有效诱导SMC凋亡,转BDNF基因的SMC对H2O2诱导凋亡具有明显的拮抗作用。

Effects of Brain-derived Neurotrophic Factor on H2O2-induced Apoptosis of Human Arterial Smooth Muscle Cell

OBJECTIVE: To investigate the protective effects of brain-derived neurotrophic factor (BDNF) on hydrogen peroxide (H2O2) induced apoptosis of human arterial smooth muscle cells (SMC). METHODS: The hBDNF cDNA was transfected into the SMC mediated by Lipofect- AMINE, and ectopic expression in SMC was driven by the regulatory elements of I type collagen gene(COLIA1). The cell proliferation was measured with a colorimetric assay based on the cleavage of the tetrazolium salt MTT. Microscopic analysis of cell apoptosis was performed with fluorescent stain of acridine orange (AO). Apoptosis rate of SMC was tested by flow cytometry (FCM). DNA pattern was examined by agarose gel electrophoresis. RESULTS: Exposure of growing SMC to 100-800 mumol/L H2O2 for 24 h remarkably suppressed the cell proliferation. After treatment of the cells with 200 mumol/L H2O2 for 24 h, morphological and biochemical changes of classic apoptosis such as condensation of cytoplasm, fragmentation of the nuclear chromatin, DNA "ladder" pattern after electrophoresis were observed. Yet, the above-mentioned apoptosis changes were not observed and the apoptosis rate was reduced obviously in the BDNF-transfected SMC treated with the same concentration of H2O2. CONCLUSION: H2O2 can induce apoptosis of SMC, but BDNF inhibits H2O2-induced SMC apoptosis markedly and has strong anti-apoptotic activity.