心肌细胞核钙调素Ⅰ和CREB磷酸化在压力负荷大鼠心肌肥厚中的作用  

Role of Myocardial Nuclei CalmodulinⅠand CREB Phosphorylation in Pressure Overloaded Hypertrophic Hearts in Rats

作　　者：周骐[1] 肖颖彬[1] 刘健[1] 王培勇[2] 陈林[1] 钟前进[1] 王学锋[1] 

机构地区：[1]第三军医大学新桥医院心外科,重庆400037 [2]第三军医大学新桥医院病理生理学教研室,重庆400038

出　　处：《高血压杂志》2006年第1期52-56,共5页Chinese Journal of Hypertension

基　　金：国家自然科学基金资助;(NO.30200108)

摘　　要：目的探讨钙调素Ⅰ(Ca MⅠ)及核转录因子CREB磷酸化在压力超负荷大鼠心肌肥厚中的作用。方法100只健康雄性SD大鼠随机分为对照组(n=50)和心肌肥厚组(n=50),制备腹主动脉缩窄大鼠心肌肥厚模型,模型复制成功后4周,以改良差速离心和密度梯度离心法提纯细胞核,以蛋白印迹法测定心肌细胞核CREB及磷酸化CREB(pCREB)表达,免疫组化法观察左室心肌组织Ca MⅠ蛋白表达及分布,延续转录分析法观察阻断Ca M后心肌细胞核c-fos mRNA的变化。结果与对照组比较,心肌肥厚组pCREB蛋白光密度明显增加(104·71vs75·29,P<0·05),CREB蛋白光密度无明显变化(128·43vs113·86,P>0·05);Ca MⅠ分布于细胞核及细胞浆,心肌肥厚组Ca MⅠ蛋白表达较对照组明显增加(21·64vs17·24,P<0·05);使用Ca M抑制剂后心肌肥厚组心肌细胞核c-fos mRNA表达明显降低(144·6vs54·1,P<0·05)。结论压力超负荷时心肌细胞核内Ca MⅠ蛋白表达增加,可能通过增加核转录因子CREB磷酸化,上调早期基因c-fos表达参与心肌肥厚的发生。Objective To observe the role of calmodulin Ⅰ and CREB phosphorylation in pressure over load induced hypertrophic heart in rats. Methods The model of hypertensive rats were established by abdominal aortic constriction. Velocity and isopyknic gradient centrifugation was employed to fractionate myocardial nuclei. The protein levels and phosphorylated levels of CREB in control and cardiac hypertrophy group were examined using Western blot analysis. CaM I protein expression of left ventricular tissue was analyzed by immunohistochemistry method. C-fos mRNA expression of left ventricular tissue was analyzed by reverse transcription PCR （RT-PCR） . Nuclear run off transcription assay was used to analyse c-fos mRNA when myocardial nuclei incubated with CaM antagonist. Results CaMⅠ protein were expressed in both myocardial nuclei and myocardial cytoplasm. The level of CaM Ⅰwas significantly higher in cardiac hypertrophy group compared with that in control group（ 104.7 vs 75.3, P〈0. 05 ）. The protein level of CREB was of little differences （128. 4 vs 113. 9, P〉0.05 ） while phosphorylated CREB protein was increased（ 104.7 vs 75.3, P〈0.05 ）. C-fos mRNA was decreased when CaM was inhibited by using trifluoperazne in cardiac hypertrophy group compared with control group（ 144.6 vs 54.1, P〈0.05 ）. Conclusion CREB phosphorylation followed by CaM Ⅰ in myocardial nuclei may involve in pressure over load induced cardiac hypertrophy through up-regulated c-fos expreesion.

关 键 词：左心室肥厚 钙调素 CAMP反应元件结合蛋白 C-FOS 

分 类 号：R541.3[医药卫生—心血管疾病]