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目的探讨家兔心衰心肌细胞钙渗漏与蛋白激酶A(PKA)和Ca2+/钙调蛋白依赖性激酶Ⅱ(CaMKⅡ)表达和活性的关系。方法 30只家兔随机均分为假手术组和心衰组。通过超容量负荷联合压力负荷制备家兔心衰模型,用心脏多谱勒和心导管术测定家兔心脏功能,应用钙成像系统进行肌浆网钙回摄和钙渗漏试验。采用Western blot法和γ-32P掺入法测定CaMKⅡ和PKA的蛋白表达水平和活性;应用ELISA法测定血浆去甲肾上腺素(NE)、肾上腺素(E)和脑钠肽(BNP)水平。结果与假手术组相比,心衰组家兔左室舒张末压、血浆NE、E和BNP水平均明显增加(P<0.01),而射血分数明显降低(P<0.01),肌浆网钙回摄功能下降(P<0.05),而钙渗漏增加(P<0.01),PKA的蛋白表达水平和活性均下降(P<0.05),而CaMKⅡ蛋白表达水平和活性均增加(P<0.05)。结论家兔心衰心肌细胞钙渗漏与CaMKⅡ蛋白表达水平和活性增加相关。
Objective To investigate the relationship between calcium leakage and expression of protein kinase A (PKA) and Ca2 + / calmodulin-dependent kinase Ⅱ (CaMKII) in rabbits with heart failure. Methods Thirty rabbits were randomly divided into sham operation group and heart failure group. Rabbit heart failure model was prepared by super-capacity load combined with pressure load. Cardiac function was measured by cardiac Doppler and cardiac catheterization. Calcium imaging system was used to detect sarcoplasmic reticulum calcium flux and calcium leakage. Western blot and γ-32P incorporation method were used to determine the protein expression level and activity of CaMK Ⅱ and PKA. The levels of plasma NE, NE and BNP were measured by ELISA. Results Compared with the sham operation group, the left ventricular end-diastolic pressure, NE, E and BNP levels of rabbits in heart failure group were significantly increased (P <0.01), while the ejection fraction was significantly lower (P <0.01) (P <0.05), calcium leakage increased (P <0.01), PKA protein expression and activity decreased (P <0.05), while CaMKⅡ protein expression and activity increased (P <0.05 ). Conclusion Calcium leakage in heart failure of rabbits is related to the increase of CaMKⅡ protein expression and activity.