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心肌细胞核钙调素Ⅰ介导的bcl-2转录调节在大鼠心肌肥厚中的作用

周骐, 肖颖彬, 刘健, 王培勇, 陈林, 钟前进, 王学锋

第三军医大学新桥医院心外科.重庆 400037；第三军医大学病理生理学教研室.重庆 400038

摘要

为探讨心肌细胞核钙调素Ⅰ(calmodulinⅠ, CaMⅠ)介导的{sl bcl--2}转录调节在大鼠心肌肥厚中的作用及其可能机制， 实验随机分为对照组和心肌肥厚组，采用腹主动脉缩窄法制备大鼠心肌肥厚模型。模型复制成功后 4周，以改良差速离心和密度梯度离心提取并纯化细胞核；蛋白印迹法测定心肌细胞核 cAMP反应元件结合蛋白(cAMP response--element binding protein, CREB)及磷酸化CREB (phosphorylated cAMP response--element binding protein, pCREB)表达；免疫组化法观察左室心肌组织CaMⅠ蛋白表达及分布；延续转录分析法观察阻断CaMⅠ后心肌细胞核 {sl bcl--2} mRNA的变化。结果表明，心肌肥厚组pCREB蛋白表达较对照组明显增加({sl P}<0.05)，CREB蛋白表达无明显变化({sl P}>0.05); CaMⅠ分布于细胞核及细胞浆，心肌肥厚组CaMⅠ蛋白表达较对照组明显增加( {sl P}<0.05); 使用CaM抑制剂后心肌细胞核{sl bcl--2} mRNA表达明显上调({sl P}<0.05)。结果提示，压力超负荷时心肌细胞核内CaMⅠ激活，抗凋亡基因{sl bcl--2}表达下调，核转录因子CREB磷酸化增加，但CREB 在调节{sl bcl--2}基因转录过程中可能发挥次要作用。

关键词： 心肌肥厚; 钙调素; cAMP反应元件结合蛋白; 凋亡

Role of bcl-2 transcriptional regulation induced by calmodulin Ⅰin pressure overload rat hypertrophic hearts

Zhou Qi, Xiao Yingbin, Liu Jian, Wang Peiyong, Chen Lin, Zhong Qianjin, Wang Xuefeng

Department of Cardiovascular Surgery, Xinqiao Hospital.Chongqing 400037；China

Abstract

This study was designed to evaluate the role of bcl-2 transcriptional regulation induced by calmodulinⅠ(CaMⅠ) in pressure overload rat hypertrophic hearts. The model of hypertensive Sprague-Dawley rat was established by abdominal aortic constriction. The hearts were collected four weeks after abdominal aortic constriction. Velocity and isopyknic gradient centrifugation was employed to fractionate rat myocardial nuclei. Western blot analysis revealed a marked increase in phosphorylated cAMP response-element binding protein (pCREB) of cardiac hypertrophy group compared with that in control group (P<0.05), while the protein level of cAMP response-element binding protein (CREB) was constant (P>0.05). Immunohistochemistry results showed a significant increase of CaMⅠprotein in cardiac hypertrophy group relative to the control group (P<0.05). Nuclear run off transcription assay displayed a significant increase in bcl-2 mRNA treated with trifluoperazne compared with non-drug treatment (P<0.05).The results obtained suggest that the transcription of bcl-2 is possibly regulated by CaMⅠin hypertrophic rat hearts, and CREB phosphorylation seems to be a minor factor in bcl-2 transcriptional regulation.

Key words: Myocardial hypertrophy;Calmodulin;cAMP response-element binding protein;Apoptosis

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引用本文：

周骐, 肖颖彬, 刘健, 王培勇, 陈林, 钟前进, 王学锋. 心肌细胞核钙调素Ⅰ介导的bcl-2转录调节在大鼠心肌肥厚中的作用[J]. 生理学报 2005; 57 (6): .

Zhou Qi, Xiao Yingbin, Liu Jian, Wang Peiyong, Chen Lin, Zhong Qianjin, Wang Xuefeng. Role of bcl-2 transcriptional regulation induced by calmodulin Ⅰin pressure overload rat hypertrophic hearts . Acta Physiol Sin 2005; 57 (6): (in Chinese with English abstract).