BAPTA对去甲肾上腺素刺激的大鼠心肌细胞蛋白合成及c-fos和β-MHC表达的影响

Effect of Ca^(2+) chelator BAPTA on protein synthesis and expression of c-fos and β-MHC in rat myocardial cells stimulated by norepinephrine

目的观察去甲肾上腺素(norep inephrine,NE)刺激导致的心肌细胞肥大中,钙信号通路和心肌细胞蛋白合成以及c-fos和β-MHC表达之间的关系。方法去甲肾上腺素(10-5mol/L)刺激原代培养的心肌细胞,细胞内钙离子络合剂BAPTA(20μmol/L)阻断钙信号通路,通过3H-leuc ine掺入测定蛋白质合成,RT-PCR测定c-fos及β-MHC mRNA的表达。结果NE刺激组的心肌细胞3H-leuc ine摄入量、c-fos及β-MHC的表达均显著高于正常对照组(P<0.01),BAPTA阻断后明显降低(P<0.01),单纯BAPTA阻断组的3H-leuc ine摄入量和β-MHC的表达低于正常对照组(P<0.01),在正常对照组及单纯BAPTA阻断组未见c-fos明显表达。结论Ca2+信号通路不但参与NE刺激引起的心肌细胞蛋白合成增加、c-fos及β-MHC的过度表达,且在正常心肌细胞蛋白质合成及β-MHC表达中也起重要作用。

Objective To investigate the relationship between the Ca^2＋ signal transduction and protein synthesis, c-fos and β-MHC expression in rat hypertrophic myocardial cells stimulated by norepinephrine （NE）. Methods Neonatal Wistar rats of 1 - 2 d were used to culture the myocardial cells and the cells were stimulated by NE and blocked the Ca^2＋ signal transduction by BAPTA （intracellular Ca^2＋ chelator）, then applied to detect and compare the protein synthesis by ^3 H-leucine incorporation and the expression of c-fos and β- MHC mRNA with RT-PCR. Results The ^3H-leucine incorporation rate, c-fos and β-MHC expression of myocardial cells stimulated by NE were obviously higher than the control and could be blocked by BAPTA （P 〈 0. 01 ）. The ^3H-leucine incorporation rate and β-MHC expression in the cells that were treated only with BAPTA was lower than the normal myocardial cells （ P 〈 0. 01 ）. No obvious expression of c-fos was found in the cells treated only by BAPTA and the normal myocardial cells. Conclusion Ca^2＋ signal not only plays a role in protein synthesis, c-fos and β-MHC overexpression in hypertrophic myocardial cells stimulated by NE, but also is necessary in protein synthesis and β-MHC expression in normal cells.