异钩藤碱通过下调CaN、ERK2和上调MKP-1的表达抑制大鼠心肌细胞肥大

Isorhynchophylline inhibits the cardiomyocyte hypertrophy in neonate rats by the down-regulation of CaN and ERK2 mRNA expressions and up-regulation of MKP-1 protein expression

目的研究异钩藤碱抑制大鼠心肌细胞肥大的作用并探讨其可能的作用机制。方法采用乳SD大鼠原代心肌细胞培养法,建立心肌细胞肥大模型;HE染色观察细胞形态学变化,采用图像分析系统测量心肌细胞的表面积、BCA法测定细胞蛋白质含量,确定药物抑制心肌细胞肥大的作用;实时荧光定量PCR检测细胞中CaN及ERK2 mRNA的表达、Western blotting检测细胞中MKP-1蛋白的表达,探讨药物作用的可能机制。结果异钩藤碱1μmol/L、10μmol/L明显抑制AngⅡ诱导心肌细胞表面积和蛋白含量的增加,改善心肌细胞形态学;明显抑制AngⅡ所致CaN、ERK2 mRNA表达的增加,而各浓度组则显著升高MKP-1蛋白的表达。结论异钩藤碱具有抑制大鼠心肌细胞肥大的作用,其机制可能与抑制AngⅡ所致CaN、ERK2 mRNA表达和升高MKP-1蛋白的表达有关。

Objective To investigate the effects of isorhynchophylline （Iso） on rat cardiomyocyte hy- pertrophy induced by angiotensin Ⅱ（ Ang Ⅱ） and further explore the possible mechanisms. Methods Pri- mary cardiomyocytes from neonatal SD rats were cultured in vitro to establish the cardiomyocyte hypertro- phy model. Cell morphological changes were analyzed by HE staining and the cardiomyocyte surface are- a was measured by Leica Qwin V3 imaging analytic system. Protein content was detected by BCA assay to investigate the inhibitiory effects of Iso. The expressions of extracellular signal - regulated kinase 2 （ ERK2 ） and calcineurin （CaN） mRNA in cardiomyocytes were measured by real -time RT- PCR and MAPK Phosphatase - 1 （ MKP - 1 ） examined by western blotting assay for exploring the possible mecha- nisms. Results Iso （ 1 and 10 μmol/L） significantly inhibited the increase of cardiomyocyte surface area and protein content and improved the cardiomyocyte morphological damage induced by Ang Ⅱ. Simulta- neously, Iso （ 0.1,1 and 10 μmol/L） decreased the elevated CaN and ERK2 mRNA expressions in- duced by Ang Ⅱ and up - regulated the MKP - 1 protein expression. Conclusion Iso could significantly attenuate the cardiomyocyte hypertrophy and this effect appears to be related to increasing MKP - 1 pro- tein expression and decreasing CaN and ERK2 mRNA expressions.