生长激素对老龄大鼠缺血再灌注心肌的保护作用

目的通过老龄大鼠心肌缺血再灌注模型,术后应用生长激素(GH),观察其对心肌细胞凋亡、心肌胰岛素样生长因子含量以及心脏功能的影响。方法24只老龄SD大鼠(20月龄)随机分为对照组、治疗组,每组12只。结扎左前降支缺血10min制作心肌缺血再灌注模型,对照组皮下注射生理盐水(0.3ml/d)。治疗组每天皮下注射人重组生长激素(rhGH)0.5U/kg,连续7d,第7次注射于术前进行。在体法检测心功能,TUNEL法检测心肌细胞凋亡,DAB免疫组织化学法检测心肌细胞胰岛素样生长因子含量,并行心肌组织病理学检查。结果心肌病理检查见心肌缺血区呈大小不一坏死灶,缺血心肌间有炎症细胞浸润,心肌排列不整齐,治疗组轻于对照组。治疗组心肌细胞凋亡率明显低于对照组(P<0.01),胰岛素样生长因子染色强度明显高于对照组(P<0.01),心功能优于对照组(P<0.05)。结论老龄大鼠心肌缺血再灌注后应用生长激素,可减轻心肌细胞凋亡,提高心肌胰岛素样生长因子含量,保护心功能。

Protective effect of growth hormone on ischemia reperfusion myocardium in aged rats

Objective To study the effect of growth hormone (GH) on myocardial apoptosis. insulin-like growth factor-1(IGF-1) dyed intensity and cardiac function in aged rat with experimental myocardial ischemia/reperfusion injury.Method Twenty -four aged rats (20 months old) were divided randomly into two groups control group (n=12) and GH group (n=12).10 minute's ischemia followed by 7 day's reperfusion were performed in all groups. The rats in GH group were treated with subcutaneous injection of GH 0.5U/kg per day for 7 days and the seventh injection began at preoperation. and the rats in control group were treated with subcutaneous injection of normal saline 0.3 ml per day. Then the indices of left ventricular pump function were determined.TUNEL and DAB immunohistochemical staining were used to detect the myocardial apoptosis and IGF-1 respectively. Histopathological changes of myocardium was observed by HE dye. Results Apoptotic index (AI) was obviously higher in control group than that of GH group (P<0.01). Myocardium dyed intensity of IGF-1 was higher in GH group than that of control group (P<0.01). cardiac function was better in GH group. Necrosis and inflammatory cell infiltration in control group were more seriously.Conclusion Growth hormone can decrease myocardial apoptosis. increase IGF-1 dyed intensity and protect cardiac function in aged rat with experimental myocardial ischemia/reperfusion injury.