κ-阿片受体激动剂U50,488H抑制缺血/再灌注心肌线粒体分裂的作用及机制

王渊博; 周亚光; 田心; 王旭; 张淑苗; 冯娜; 李娟; 王跃民; 顾晓明; 付锋; 裴建明

doi:10.12125/j.chj.201806070

κ-阿片受体激动剂U50,488H抑制缺血/再灌注心肌线粒体分裂的作用及机制

κ-opioid receptor agonist U50, 488H inhibits mitochondrial fission induced by myocardial ischemia-reperfusion and its underlying mechanism

摘要

摘要:
目的研究外源性κ-阿片受体激动剂U50,488H对缺血/再灌注心肌线粒体分裂的影响及机制。
方法将SD大鼠随机分为6组：假手术（Sham）组，心肌缺血/再灌注（MI/R）组，MI/R+κ-阿片受体激动剂U50,488H（MI/R+U）组，MI/R+κ-阿片受体阻断剂nor-BNI+U50,488H（MI/R+N+U）组，MI/R+磷脂酰激醇3-激酶（pi 3-kinases，PI3K）抑制剂wortmannin+U50,488H（MI/R+W+U）组，MI/R+蛋白激酶B（protein kinase B, Akt）抑制剂MK2206+U50,488H（MI/R+M+U）组。血清肌酸激酶（creatine kinase, CK）试剂盒检测血清CK水平；三苯基氯化四氮唑（triphenyte-trazoliumchloride, TTC）-伊文氏蓝双染检测心肌梗死面积；Western blotting检测细胞内磷酸化PI3K、磷酸化Akt（Ser 473）、磷酸化线粒体动力学分裂相关蛋白（dynamin-related protein, Drp）1（Ser 637）的表达；透射电镜观察线粒体形态。
结果与Sham组相比，MI/R组血清CK水平明显升高（P<0.01），出现明显的心肌梗死（P<0.01），磷酸化PI3K、磷酸化Akt表达增加（P<0.05），磷酸化Drp1表达降低（P<0.01），线粒体分裂明显增加（P<0.01）；与MI/R组相比，MI/R+U组血清CK水平明显降低（P<0.01），心肌梗死面积减小（P<0.01），磷酸化PI3K、磷酸化Akt和磷酸化Drp1的表达显著增加（P<0.01），线粒体分裂减少（P<0.01）。给予nor-BNI、wortmannin或MK2206后，U50,488H的上述作用均被阻断。
结论缺血/再灌注可引起心肌损伤和线粒体分裂增加，κ-阿片受体激活后通过PI3K-Akt通路使Drp1磷酸化增加，抑制缺血/再灌注心肌的线粒体分裂，减轻心肌损伤。

Abstract:
AIMTo investigate the effects of U50,488H, a selective kappa-opioid receptor agonist, on mitochondrial fission induced by myocardial ischemia/reperfusion (MI/R) and its underlying mechanisms.
METHODSSprague Dawley rats were randomly assigned into six groups: Sham group; MI/R group; MI/R + U50,488H (MI/R + U) group; MI/R + nor-BNI (a selective kappa-opioid receptor antagonist) + U50,488H (MI/R + N + U) group; MI/R + Wortmannin (a PI3K inhibitor) + U50,488H (MI/R + W + U) group; and MI/R + MK2206 (an Akt inhibitor) + U50,488H (MI/R + M + U) group. Serum creatine kinase (CK) levels were determined by CK kit and myocardial infarct size was analyzed by TTC/Evens blue double staining. Western blotting was used to examine the expressions of phosphorylated PI3K, phosphorylated Akt (Ser 473) and phosphorylated Drp1 (Ser 637) and transmission electron microscope was used to evaluate mitochondrial morphology.
RESULTSCompared with the sham group, MI/R group exhibited increased serum CK (P<0.01), obvious infarct area and enhanced mitochondrial fission (P<0.01), which were accompanied by increased expressions of phosphorylated PI3K and phosphorylated Akt (P<0.05)and decreased expressions of phosphorylated Drp1 (P<0.01). Compared with MI/R group, MI/R + U group showed decreased serum CK (P<0.01), reduced myocardial infarct size (P<0.01), inhibited mitochondrial fission and increased expressions of phosphorylated PI3K, phosphorylated Akt and phosphorylated Drp1 (P<0.01). The above effects of U50,488H were blunted by nor-BNI, wortmannin or MK2206.
CONCLUSIONMI/R causes myocardial injury and mitochondrial fission. Activation of κ-opioid receptor reduces MI/R injury and inhibits mitochondrial fission by increasing the phosphorylation of Drp1 at Ser 637 via PI3K/Akt signaling.

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