Spironolactone Inhibits Cardiomyocyte Hypertrophy by Regulating the Ca 2+ /Calcineurin/p-NFATc3 Pathway.

This study aimed to investigate the protective effect and molecular mechanism of spironolactone in isoproterenol-induced cardiomyocyte hypertrophy. In this study, primary cardiomyocytes were extracted from the heart of neonatal rats. After stable culture, they were processed with isoproterenol alone or isoproterenol (10  μ M) combined with different doses (low dose of 10  μ M and high dose of 50  μ M), and the cellular activity was determined by MTT experiment. The volume of cells was measured with an inverted microscope and CIAS-1000 cell image analysis system. The mRNA expression levels of ANP and BNP in cells were explored by RT-qPCR. The levels of ANP and BNP proteins and NFATc3 phosphorylation in the nucleus were detected by western blot. The extracellular Ca2 + concentration and CaN activity were measured by colorimetry with the kit. Isoproterenol significantly enlarged the volume of cardiomyocytes ( p < 0.001), upregulated mRNA and expression levels of ANP and BNP proteins ( p < 0.001), increased extracellular Ca 2+ concentration and CaN activity ( p < 0.001), and upregulated NFATc3 phosphorylation in the nucleus ( p < 0.001). The volume of cells treated with isoproterenol combined with different doses of spironolactone significantly decreased compared with those treated with isoproterenol alone ( p < 0.001). mRNA and expression levels of ANP and BNP proteins downregulated significantly ( p < 0.001). The extracellular Ca 2+ ( p < 0.01) concentration and CaN activity ( p < 0.001) decreased significantly, and NFATc3 phosphorylation in the nucleus downregulated significantly ( p < 0.001). There was no significant difference in cell volume ( p =0.999), ANP and BNP mRNA ( p =0.695), expression levels of proteins, CaN activity (0.154), and NFATc3 phosphorylation in the nucleus between the cells treated with isoproterenol combined with high-dose spironolactone and those in the control group. In conclusion, spironolactone can reverse isoproterenol-induced cardiomyocyte hypertrophy by inhibiting the Ca 2+ /CaN/NFATc3 pathway.