δ阿片受体激活对依赖于PKC路径的血清饥饿诱导的心肌细胞凋亡的抑制作用

δ-Opioid receptor inhibits serum deprivation-induced apoptosis of neonatal cardiac myocytes through activation of protein kinase C signal transduction pathway

目的探讨δ阿片受体激活对血清饥饿诱导的心肌细胞凋亡的抑制作用及机制。方法新生大鼠心肌细胞分为对照、模型、D-丙(2)-D-亮(5)脑啡肽DADLE 0.1μmol.L-1;DADLE 0.1μmol.L-1+naltrindole(δ阿片受体拮抗剂)10μmol.L-1、DADLE 0.1μmol.L-1+GF109203X 10μmol.L-1、DADLE 0.1μmol.L-1+staurosporine 1μmol.L-1组;分组给药48 h后,MTT法检测细胞存活率;流式细胞仪测心肌细胞的凋亡指数;流式细胞仪检测细胞周期。Western blot法检测心肌细胞的胞质内半胱氨酸天冬氨酸蛋白酶-3(caspase-3)表达及蛋白激酶C(PKC)的表达。结果δ阿片受体激动剂DADLE能明显抑制由血清饥饿引起的心肌细胞的凋亡,表现为细胞存活率升高,凋亡率下降,G0/G1百分比降低,G2/M百分比增加;caspase-3蛋白表达明显下降;PKC蛋白表达明显升高;加入naltrindole可以阻断DA-DLE对心肌细胞凋亡的抑制作用,加入GF109203X和stau-rosporine可明显拮抗DADLE抑制由血清饥饿引起的心肌细胞的凋亡的作用,表现为细胞存活率降低,凋亡率升高;G0/G1百分比增加,G2/M百分比降低;caspase-3的蛋白表达明显升高;PKC表达明显降低。结论δ阿片受体激活后通过活化PKC通路抑制血清饥饿所致的心肌细胞凋亡。

Abstract：Aim To investigate the possible mechanism of δ-opioid receptor inhibiting serum deprivation-in- duced apoptosis of neonatal cardiac myocytes. Methods Myocardial cells of neonatal rats were cultured in vitro, after 48 h, the medium was changed to serum-free DMEM. The experimental groups were ： A ： Normal ; B ： Model;C： Model ＋ DADLE（0.1 μmol·L-1）;D： Model ＋ DADLE （0. 1 μmol·L-1 ） ＋ naltrindole （ 10 μmol·L-1 ） ; E ： Model ＋ DADLE （ 0. 1 μmol·L-1 ） ＋ GF109203X （ 10 μmol·L-1 ） ; F： Model ＋ DADLE （0.1 μmol·L-1） ＋staurosporine（1 μmol·L-1）. The cell viability was determined with MTT colormeteric assay;apoptosis index and the percentage of GO in cell cycle were determined by flow cytometry;Caspase- 3 and PKC signal pathway was investigated by Western blot. Results 8 - opioid receptor agonist [ D - Ala2 ,D-Leu5] - enkephalin （DADLE） could significantly in- hibit serum deprivation-induced apoptosis of neonatal cardiac myocytes,which increased the survival index of cardiac myocyte, percentage of G2/M in cell cycle and the expression of PKC, decreased the apoptotic index of cardiac myocyte,percentage of G0/G1 in cell cycle and the expression of activate caspase-3. The protective effect of DADLE was obviously blocked by δ-opioid receptor antagonist Nahrindole at 10 μmol·L-1, the PKC inhibitor GF109203X at 10 μmol·L-1 and stau- rosporine at 1 μmol·L-1,which decreased the survival index of cardiac myocyte, percentage of G2/M in cell cycle and the expression of PKC, increased the apoptotic index of cardiac myocyte, percentage of G0/G1 in cell cycle and the expression of caspase-3. Conclusion These findings ration might be depri cardi Key vation-induc suggested that δ-opioid receptor acti- potential survival factor against serum ed myocardial cell apoptosis and this oprotective effect might be via PKC pathway.