黄芪对乳鼠肥大心肌细胞钙瞬变及钙调蛋白激酶Ⅱ的影响

Effect of Astragalus membranaceus on neonatal rat myocardial cells calcium transients and calmodulin kinase II

目的:研究黄芪注射液对体外培养乳鼠肥大心肌细胞内钙瞬变及钙调蛋白激酶Ⅱ(CaMKⅡ)的影响。方法:原代培养乳鼠心肌细胞,分为对照组(不加任何干预因素)、模型组(AngⅡ刺激心肌细胞肥大)、黄芪组(AngⅡ+黄芪注射液)。MTT法确定最佳检测时间,激光共聚焦显微镜检测单个心肌细胞(给予KN-93前后)钙瞬变。Western blot法检测CaMKⅡδ蛋白含量。结果:①AngⅡ作用48h后乳鼠心肌细胞存活率下降(P<0.05);②与对照组相比,模型组总蛋白含量显著增加,黄芪组较模型组显著下降;③与对照组相比,模型组钙瞬变荧光强度变化率降低,达峰时间、峰回落时间显著增高,黄芪治疗后钙瞬变荧光强度变化率回升,并降低峰回落时间与达峰时间;④与对照组相比,模型组CaMKⅡδ的蛋白含量显著增加,黄芪组较之模型组则显著下降。⑤与对照组相比,给予KN-93后模型组仅使峰回落时间显著增加,黄芪组较模型组可显著降低峰回落时间。结论:黄芪注射液可抑制心肌细胞肥大,其机制可能与抑制钙调蛋白激酶途径中CaMKⅡδ的表达改善收缩功能有关,并可能通过其他机制而改善舒张功能。

Objective：To study the effect of Raidx Astragali on calcium transient and calmodulin kinase U in hypertrophic cardiacmyocyte. Methods： Cultured cell derived from neonatal heart were divided into 3 groups： control group; model group： cells were stimulated by Ang Ⅱ （ 10.7 mol/L） ; Astragali group： ceils were treated with Astragali injection（10μg/L） and Ang Ⅱ. Use MTT method to determine the testing time. The effect of Raidx Astragali in treatment on the calcium transient was observed by Laser Scanning Confocal Microscopy that scanned the individual myocardial cells with KN-93 or not. The protein level of CaMK Ⅱ was detected by Western blot. Results ：Cells treated with Ang Ⅱ for 48h were chosen as hypertrophic cardiacmyocyte model. Ang Ⅱ promoted protein cardiacmyocyte synthesis. The protein level of CaMK II was significantly increased in the model group as compared with control group and treatment group. Compared with the control group and treatment group the Ang Ⅱ not only decreased the Fluo-4 ratio, but also increased the relaxation time to 50% baseline（RTS0）. The RTS0 was significantly increased in the model group with KN-93, but no effect on the Fluo-4 ratio as compared with control group and all treatment groups. Conclusion： The activation of CaMK Ⅱ played an important role in cardiomyocytes hypertrophy. Raidx Astragali prevents the hypertrophy of cardiomyocytes partially by inhibiting the expression of CaMK Ⅱ to regulate the systolic functions, and regulate the diastolic： functions partially by other mechanism.