生长激素预处理对大鼠心肌缺血再灌注后心肌细胞凋亡的影响

目的　探讨生长激素 (GH)预处理对大鼠心肌缺血再灌注 (I/ R)后心肌细胞凋亡及胰岛素样生长因子 (IGF- 1 )蛋白表达的影响。　方法　 2 4只大鼠随机分为假手术组 (仅手术 2 4 h,无 I/ R过程 )、心肌 I/ R组、GH组 ,每组 8只。后两组均缺血 30 m in,再灌注 2 4 h,GH组每天皮下肌注 GH1 U/ kg,连续 7d,第 7次注射于术前进行。另两组皮下肌注生理盐水 (0 .5 m L/ d)。 TU NEL 法检测心肌细胞凋亡 ,DAB免疫组织化学法检测心肌细胞IGF- 1蛋白表达 ,心肌组织病理学检查。　结果　心肌 I/ R2 4 h后心肌细胞凋亡指数 (AI)明显上升 (与对照组比较 ,P<0 .0 5 )。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。GH组心肌细胞凋亡率明显小于 I/ R组 (P<0 .0 5 ) ,IGF- 1染色强度明显高于另外两组 (P<0 .0 5 ) ,心肌细胞间炎症细胞、坏死灶少于I/ R组。　结论　 GH可以减轻大鼠 I/ R后心肌细胞凋亡 ,GH预处理对 I/ R后的心肌具有保护作用

Effect of Preconditioning Growth Hormone on Myocardial Apoptosis during Experimental Myocardial Ischemia/Reperfusion in Rat

Objective To study effect of the preconditioning growth hormone on myocardial apoptosis with experimental myocardial ischemia/reperfusion(I/R) injury in rat. Methods Twenty-four rats were divided randomly into three groups(n=8, each group) sham operated group(only operated for 24 h, without I/R procedure), was I/R group and growth hormone(GH) group, 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 GH 0.1 U/kg body weight per day for 7 d before operation, and the rats in other groups were treated with subcutaneous injection of normal saline 0 5 mL per day as control. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL) and DAB immunohistochemical staining were used to detect the changes of apoptosis and insulin like growth factor-1(IGF-1) expression. Results Apoptotis index(AI) increased obviously in I/R group than that of sham operated group(P<0 05). Local myocyted necrosis and inflammatory cell infiltration in I/R group were also observed. On the contrary, AI in GH group was lighter and IGF-1 expression was higher than that of I/R group(P<0 05). Local myocyte necrosis and inflammatory cell infiltration were diminished in the GH group than that of I/R group. Conclusion The AI lessened and myocardium IGF-1 expression increase obviously due to usage of GH. GH can protect myocardium in I/R.;