生长激素预处理对大鼠心肌缺血再灌注后细胞凋亡与能量代谢的影响

目的研究生长激素预处理对大鼠心肌缺血再灌注后心肌细胞凋亡及能量代谢的影响。方法42只大鼠采用完全随机设计方法分为3组，假手术组14只（假手术24h）、心肌缺血再灌注组14只、生长激素组14只，后2组均缺血30min，再灌注24h，其中生长激素组的每只大鼠术前皮下肌肉注射生长激素1 U／kg，连续7d，其中第7次皮下注射于手术前进行。前2组每只大鼠相应皮下肌肉注射生理盐水0．5ml／d。每组中均抽取8只大鼠，以TUNEL法检测缺血区心肌细胞凋亡情况，每组中剩余的抽取5只大鼠，以高效液相色谱法测定缺血区心肌三磷酸腺苷（ATP）并进行心肌组织病理、电镜超微结构观察。结果与假手术组比较，心肌缺血再灌注组再灌注24h后缺血区心肌细胞凋亡率和ATP消耗程度均明显上升（P〈0．05），心肌组织病理和超微结构改变明显；与心肌缺血再灌注组比较，生长激素组再灌注24h后缺血区心肌细胞凋亡率和ATP消耗程度均明显改善（P〈0．05），心肌组织病理和超微结构改变明显减轻。结论生长激素能减少心肌缺血再灌注后心肌细胞凋亡和ATP的消耗，说明生长激素对心肌缺血再灌注后的心肌具有保护作用。

Effect of growth hormone preconditioning on apoptosis and energy metabolism in rats with experimental myocardial ischemia reperfusion injury

Objective To study the effect of growth hormone preconditioning on apoptosis and energy me tabolism in mrs with experimental myocardial ischemia reperfusion injury.Methods Forty-two rats were divided randomly into three groups:sham operated group(n=14,sham operated for 24h),IR group(n=14) and GH group(n=14).30 min ischemiafollowing by 24h reperfusion were performed in IR group and GH group.The rata in GH group were treated with subcutaneous injection of GH 0.1 U/kg body weisht per day for 7d and seventh injection was administered before the surgery.Each rat from otller groups was treated with subcutaneous injection of normal saline 0.5 ml per day.Eight rats were randomly taken from each group and terrainal deoxynueleotidyl trarm ferase mediated dUTP fluoreseein nick and labeling(TUNEL)was used to detect the changes of apoptosis.Five rats were randomly taken from each group and ATP of ischemic myocardium was measured by high-performance liquid chromatography(HPLC).Histopathology and electronic ultrastrueture of myocardial tissue were observed.Remrs Apoptosis index(AI) and depletion of ATP increased remarkably in IR group than that of sham operated group 24h after reperfusion (P＜0.05).111e rein/irkabie changes of myocardial histopathology and ultrastructure were ob served in IR group.Compared to IR group.AI and depletion of ATP in GH group were better than that of IR group 24h after reperfusion(P＜0.05),and the changes of myocardial histopathology and uhrastrueture were alleviated in GH group.Conclusion The AI and depletion of ATP were lessened due to usage of GH which indieates that GH can protect myocardium after IR.