RESUMO
OBJECTIVE@#To investigate whether CaN-NFAT3 pathway mediates the protective effects of aldehyde dehydrogenase (ALDH) 2 in high glucose-treated neonatal rat ventricular myocytes.@*METHODS@#The ventricular myocytes were isolated from the heart of neonatal (within 3 days) SD rats by enzyme digestion and cultured in the presence of 5-Brdu. After reaching confluence, the cultured ventricular myocytes were identified using immunofluorescence assay for -SA protein. The cells were then cultured in either normal (5 mmol/L) or high glucose (30 mmol/L) medium in the presence of ALDH2 agonist Alda-1, ALDH 2 inhibitor Daidzin, or Alda-1 and NFAT3 inhibitor (11R-VIVIT). Fluorescent probe and ELISA were used to detect intracellular Ca concentration and CaN content, respectively; ALDH2, CaN and NFAT3 protein expressions in the cells were detected using Western blotting.@*RESULTS@#Compared with cells cultured in normal glucose, the cells exposed to high glucose showed a significantly decreased expression of ALDH2 protein ( < 0.05) and increased expressions of CaN ( < 0.05) and NFAT3 proteins with also increased intracellular CaN and Ca concentrations ( < 0.01). Alda-1 treatment significantly lowered Ca concentration ( < 0.05), intracellular CaN content ( < 0.01), and CaN and NFAT3 protein expressions ( < 0.05), and increased ALDH2 protein expression ( < 0.05) in high glucose- exposed cells; Daidzin treatment significantly increased Ca concentration ( < 0.01) and intracellular CaN content ( < 0.05) in the exposed cells. Compared with Alda-1 alone, treatment of the high glucose-exposed cells with both Alda-1 and 11R-VIVIT did not produce significant changes in the expression of ALDH2 protein (>0.05) but significantly reduced the expression of NFAT3 protein ( < 0.05).@*CONCLUSIONS@#Mitochondrial ALDH2 protects neonatal rat cardiomyocytes against high glucose-induced injury possibly by negatively regulating Ca-CaN-NFAT3 signaling pathway.