重组人血管内皮抑素诱导大鼠心肌细胞凋亡的体内实验研究

Experimental research on recombinant human endostatin-induced cardiomyocyte apoptosis in rats

目的探讨重组人血管内皮抑素(rh-ES)对大鼠心肌的毒性作用及其可能机制。方法 24只成年雌性Wistar大鼠随机分为rh-ES低、中、高剂量组[分别予3、6、12mg/(kg·d)rh-ES腹腔注射]及对照组(腹腔注射等体积生理盐水),每组6只。各组在第4周和第8周末次给药后采用脊椎脱臼法分别处死3只大鼠,在光镜及电镜下观察病理形态学及超微结构改变,TUNEL法检测大鼠心肌细胞凋亡情况,CD34标记内皮细胞免疫组化法检测大鼠心肌组织的微血管密度(MVD)改变。结果光镜及电镜下对照组和低、中剂量组无明显心肌损伤的病理形态及超微结构改变。高剂量组光镜下可见心肌损伤的病理形态及超微结构改变。TUNEL法检测显示,给药8周后中剂量组和高剂量组凋亡指数明显高于对照组,差异有统计学意义(P=0.033、P=0.000),其中高剂量组凋亡指数最高。心肌组织微血管计数提示,给药4周及8周后高剂量组(MVD)增加,显著高于对照组(P<0.05)。结论 rh-ES对大鼠心肌细胞具有毒性作用,细胞凋亡机制参与了心肌损伤的病理过程。

Objective To explore the recombinant human endostatin （rh-ES）-induced cardiotoxicity in rats and its mechanism. Methods Twenty four female Wistar rats were randomly divided into four groups （6 each）. Rats in low, moderate and high dose group received rh-ES with a dosage of 3, 6 and 12mg/（kg.d）, respectively, by intraperitoneal injection, and rats in control group received the same amount of normal saline alone. Half of rats in each group were sacrificed by spinal dislocation after 4 weeks and 8 weeks of the treatment. Pathomorphologic and uhrastructural changes in rat＇s myocardial tissue were evaluated by light microscopy and transmission electron microscopy. Cardiomyocyte apoptosis was detected with TdT-mediated dUTP nick end labeling （TUNEL） assay. Microvessel density （MVD） in myocardial tissue was measured by immunohistochemically marking endothelial cell with CD34. Results No pathomorphologic and ultrastrucural changes were found under light microscope and transmission electron microscope in the low dose and moderate dose groups, but cardiomyocyte damage were found in the high dose group. TUNEL assay revealed more apoptotic cells in high and moderate （only 8 weeks） dose groups than in control group （P=0.033, P=0.000）, and the apoptosis index was highest in the high dose group at 8 weeks. In addition, compared with the control group, MVD significantly increased in high dose groups at 4 weeks and 8 weeks （P〈0.05）. Conclusions rh-ES induces the cardiotoxicity in rats, and cardiomyocyte apoptosis is involved in the pathological course of cardiac toxicity.