氯沙坦对大鼠心肌缺血再灌注诱导心肌细胞凋亡及对bcl-2,bax和p53基因表达的影响

The effect of losartan on cardiomyocyte apoptosis and bcl-2, bax and p53 gene expression induced by ischemia and reperfusion in rats

目的:研究氯沙坦对大鼠在体心肌缺血再灌注后细胞凋亡影响以及与bcl-2,bax和p53基因表达变化之间的关系。方法:用原位末端标记、原位杂交、免疫组化分别检测细胞凋亡、基因表达产物的mRNA和蛋白质,经图象分析系统测量阳性染色区域的平均光密度值,从而对原位杂交和免疫组化检测物质进行量化分析。大鼠分成对照组、治疗组和假手术组。结果:细胞凋亡数各组间差异非常显著(P<0.001);原位杂交和免疫组化bcl-2对照组、治疗组的升高值与假手术组之间差异显著(P<0,05),治疗组和对照组之间无显著差异(P>0.1);免疫组化bax治疗组、假手术组的降低值与对照组间差异非常显著(P<0.001),治疗组和假手术组之间无差异(P>0.9);bcl-2/bax比值由高到低分别为治疗组、对照组和假手术组。原位杂交p53各组间差异非常显著(P<0.001),假手术组>治疗组>对照组;免疫组化p53假手术组显著高于对照组和治疗组(P<0.001),治疗组和对照组间差异无显著性(P>0.1)。结论:氯沙坦可抑制缺血再灌注后心肌细胞凋亡,机制可能是通过抑制bax基因表达使bcl-2/bax比值升高,并抑制p53基因表达的降低。

Objective:To study the effect of losartan on cardiomyocyte apoptosis and bcl-2,bax and p53 gene expression induced by ischemia and reperfusion in rats. Methods:Rats were divided into therapeutic, control and sham operating group. The apoptotic cells were assessed by TUNEL staining . The protein and mRNA of gene expression were measured by immunohistochemistry and in situ hybridization histochemistry (ISHH). In order to estimate quantitatively the average optical density (OD) an image processing system was used. Results: Apoptosis were significantly different between groups (P<0. 001). Results of ISHH and immunohistochemistry measurements indicated that bcl-2 gene expression increased significantly in therapeutic and control groups in comparison with sham operating group (P< 0.05) but no significant different between therapeutic and control groups (P>0.1). Immunohistochemistry results indicted that bax gene expression decreased very significantly in therapeutic and sham operating groups in comparison with control group (P<0.001) but no significant difference between therapeutic and sham operating groups (P>0.9). The bcl-2/bax ratio value for groups in decreased order were therapeutic,control and sham operating group. ISHH results indicated that p53 gene expression was significantly difference between groups (P<0.001) and they were in the order of sham operating group>herapeutic group> control group. Immunohistochemistry results indicated that p53 gene expression in sham operating group was significantly increased in comparison with therapeutic and control groups (P<0.001) and there were no significant difference between therapeutic and control groups (P>0.1) . Conclusion: Cardiomyocyte apoptosis induced by ischemia and reperfusion in rats may be inhibited by losartan and the mechanism may be due to increase in bcl-2/bax ratio resulted from the tendency of losartan to inhibite bax gene expression.