PPARγ1基因转染对缺血再灌注心肌细胞凋亡的作用和影响

 摘要：目的  探讨心肌细胞过表达过氧化物酶体增殖物激活受体γ1（PPARγ1）基因对缺血再灌注损伤导致细胞凋亡的作用和影响。方法  30只SD大鼠随机分为SHAM组、MIRI组、PPARγ1组，每组10只。SHAM组和MIRI组经冠状动脉转染携带绿色荧光蛋白的腺病毒载体（Ad-EGFP），PPARγ1组转染携带PPARγ1基因的腺病毒载体（Ad-PPARγ1）至心肌组织。稳定3 d后，SHAM组只过线，不接扎；MIRI组和PPARγ1组行心肌缺血再灌注损伤（缺血30 min，再灌注120 min）。电镜下观察各组心肌的超微结构变化，Western blot检测B淋巴细胞瘤-2基因（Bcl2）和Bcl2相关X蛋白（Bax），DNA断裂的原位末端标记法观察心肌细胞凋亡情况。结果  缺血再灌注后，电镜下MIRI组心肌细胞结构损伤最严重，心肌纤维排列紊乱，有断裂和溶解现象，线粒体肿胀，结构模糊，部分嵴断裂溶解；PPARγ1组结构损伤较MIRI组减轻。与SHAM组比较，MIRI组Bcl2/Bax比值下降（P <0.05），PPARγ1组无明显变化（P >0.05）；与MIRI组比较，PPARγ1组Bcl2/Bax比值上升（P <0.05）。MIRI组和PPARγ1组的心肌细胞凋亡数目较SHAM组升高（P <0.05）；MIRI组高于PPARγ1组（P <0.05）。结论  过表达PPARγ1基因能通过抗氧化应激、减少细胞凋亡来保护缺血再灌注心肌。

Effects of PPAR gamma 1 gene transfection on apoptosis of cardiomyocytes after ischemia reperfusion

Abstract: Objective To explore the effect and influence of over-expression of peroxisome proliferator-activated receptor γ1 (PPARγ1) gene on the apoptosis of myocardial cells after ischemia reperfusion. Methods Thirty SD rats were randomly divided into three groups (10 in each group), i.e. group A (sham group), group B(myocardial ischemia-reperfusion group) and group C (PPARγ1 gene group). Myocardial tissues were transfected with recombinant adenovirus vector mediated enhanced green fluorescent protein (Ad-EGFP) via coronary artery in the groups A and B. Myocardial tissues were transfected with recombinant adenovirus vector mediated PPARγ1 gene (Ad-PPARγ1) in the group C. In the group A the coronary artery was crossed through with a line without ligation; while myocardial ischemia-reperfusion injury (ischemia 30 min, reperfusion 120 min) was induced in the groups B and C three days later. Under electron microscope the changes of the myocardial ultrastructures were observed. Bcl-2 and Bax expressions in the heart were detected by Western blot. TUNEL method was used to measure myocyte apoptosis. Results After ischemia and reperfusion, the cardio-myocytes in the group B were injuried most seriously under electron microscope; the myocardial fibers were arranged irregularly, ruptured and dissolved; the mitochondria were swellon with fuzzy structure and partia lcristae fragmentation and dissolution. The subcellular structure damage in the group C was milder than that of the group B. Compared with the group A, Bcl-2/Bax ratio decreased significantly in the group B (P < 0.05), but had no significant change in the group C (P > 0.05). Compared with the group B, Bcl-2/Bax ratio in the group C increased significantly (P < 0.05). The number of apoptotic cardiomyocytes in the groups B and C was significantly larger than that in the group A (P < 0.05). The number of myocardial apoptosis in the group B was significantly larger than that in the group C (P < 0.05). Conclusions Over-expression of PPARγ1 gene can protect myocardial tissues from ischemia reperfusion injury by reducing oxidative stress and cell apoptosis.