生长激素对大鼠心肌缺血/再灌注后心肌细胞凋亡及凋亡相关基因Caspase-3 Cleaved caspase-3蛋白表达的影响

Apoptosis and related gene expression of Caspase-3,Cleaved caspase-3 protein in rat With experimental myocardial ischemia/reperfusion injury

目的研究生长激素(Growth hormone,GH)对大鼠心肌缺血/再灌注(ischemia reperfusion,I/R)后心肌细胞凋亡及相关基因Caspase-3、Cleaved caspase-3蛋白表达的影响。方法24只大鼠随机分为三组,假手术组(sham-operated group,n=8,仅手术24h)、心肌缺血/再灌注(I/R)组(n=8)、GH组(n=8),后两组均缺血30min,再灌注24h,GH组于建立模型前7d每天给予人重组生长激素(reconbination human growth hormone,rhGH)针剂皮下注射(1U/kg体质量),其他二组等量生理盐水注射。以TUNEL法检测心肌细胞凋亡情况,DAB免疫组化法检测心肌细胞Caspase-3、Cleaved caspase-3蛋白表达并进行心肌组织病理学检查。结果大鼠心肌I/R24h后心肌细胞凋亡指数明显上升(对照于假手术组,P<0.05),心肌细胞Caspase-3、Cleaved caspase-3蛋白表达呈阳性染色指数明显升高(P<0.05),心肌病理检查见心肌缺血区呈大小不一的坏死灶,缺血心肌间有炎症细胞浸润,心肌排列不整齐(HE染色),而GH组心肌细胞凋亡率及心肌细胞Caspase-3、Cleaved caspase-3蛋白表达呈阳性染色指数明显好于I/R组(P<0.05),心肌细胞炎症细胞也明显减少,坏死灶也少于I/R组。结论GH可以减少心肌I/R后心肌细胞凋亡及细胞Caspase-3、Cleaved caspase-3染色阳性指数,说明GH对I/R后的心肌具有保护作用。

Objective To study effect of growth hormone on myocardial apoptosis and related gene expression of Caspase-3,Cleaved caspase-3 protein in rat with experimental myocardial ischemia/reperfusion injury.Methods Twenty-four rats were divided randomly into three groups,sham operated group（n=8,only operated for 24 h）,I/R group（n=8）and GH group（n=8）,30 min ischemia and followed by 24 h of reperfusion were performed in I/R group and GH group.The rats in GH group were treated with subcutaneous injection of rhGH 0.1 U/kg body weight per day for 7 d before models were performed,and the rats in other two groups were treated with normal saline correspondingly volume,Terminal deoxynucleotidyl transferase mediated dUTP fluoreseein nick and tabeling（TUNEL）and DAB immunohistochemical staining were used to detect the changes of apoptosis and protein expression of Caspase-3 and Cleaved caspase-3 individully,Histopathological changes in myocardium was observe by HE dyed.Results Apoptotis index（AI）and protein expression index（PEI,%）of Caspase-3 and Cleaved caspase-3 protein increased obviously in I/R group than that of sham operated group（P〈0.05）.Local myocyte necrosis and inflammatory cell infiltration in I/R group were also observed.On the contray,AI and PEI of Caspase-3 and Cleaved caspase-3 protein in GH group were batter than that of I/R group（P〈0.05）,Local myocyte necrosis and inflammatory cell infiltration diminished in the GH group than that of I/R group.Conclusion The AI and PEI of Caspase-3 and Cleaved caspase-3 protein in myocardial cell nuclear lessened obviously due to usage of GH and indicated GH can protect myocardial after I/R.