脂联素通过APPL1减轻缺氧/复氧损伤诱导的心肌细胞凋亡

目的:探讨APPL1在脂联素（adiponectin，ANP）拮抗SD乳鼠心肌细胞（neonatal cardiomyocytes）缺氧/复氧（H/R）损伤中的作用。方法: 分离SD乳鼠心肌细胞并培养。通过对培养的心肌细胞H/R损伤模拟缺血/再灌注（simulated ischemia reperfusion，SI/R）后，随机分为对照组、H/R组、H/R+APN组及H/R+APN+APPL1 RNAi组。采用四甲基偶氮唑蓝(MTT)比色法检测细胞的生存率，原位缺口末端标记(TUNEL)法检测细胞的凋亡，Western blot检测APPL1蛋白的表达。结果: 与对照组相比，H/R组吸光度值明显降低（P<0.01），凋亡指数(AI)显著上升（P<0.01）。与对照组和H/R组相比，H/R+APN组中APPL1的表达明显上升（P<0.05）。以RNAi抑制APPL1表达后，与H/R+APN组相比，H/R+APN+APPL1 RNAi组凋亡指数率(%)明显上升 ［(28.32±4.13)% vs.(9.78±2.16)%，P<0.01］。结论: APN可显著抑制H/R损伤诱导的心肌细胞凋亡，促进心肌细胞存活，其拮抗作用与上调APPL1蛋白的表达相关。

Adiponectin protects cardiomyocytes from hypoxia/reoxygenation-induced apoptosis via upregulation of APPL1

AIM: To investigate the role of APPL1 on the protective effect of adiponectin on neonatal cardiomyocytes subjected to hypoxia-reoxygenation(H/R).METHODS: Primary neonatal cardiomyocytes were isolated from the ventricles of 2-to 3-day-old Sprague Dawley(SD) rats by enzymatic digestion and were exposed to hypoxia(940 ml/L N2,50 ml/L CO2,10 ml/L O2) for 6 h followed by 12 h reoxygenation(950 ml/L air,50 ml/L CO2).Cell viability of neonatal cardiomyocytes was measured by MTT assay.Apoptosis of neonatal cardiomyocytes was detected by TUNEL and expression of APPL1 protein was analyzed by Western blot.RESULTS: Cardiomyocyte viability was reduced after H/R(P<0.01 vs.control) and the apoptosis index increased compared with the control group(P<0.01).Administration of adiponectin during reperfusion dramatically attenuated the viability and apoptosis of neonatal cardiomyocytes and upregulated APPL1 expression.To further ascertain the role of APPL1 in adiponectin-induced cardioprotective effect,neonatal cardiomyocytes were transfected with siRNA targeting APPL1,which significantly blunted the anti-apoptotic effect of adiponectin.CONCLUSION: Adiponectin exerts a protective effect on neonatal cardiomyocytes against H/R injury through upregulating APPL1 expression.