[Effect of calcineurin Aalpha gene overexpression on the myocardium apoptosis induced by hypoxia-reoxygenation and adrenergic receptors].

OBJECTIVE: To investigate the effect of calcineurin AalphacDNA (AdCnAalpha) overexpression as a result of adenovirally mediated gene transfer on neonatal rat cardiac myocyte apoptosis induced by hypoxia-reoxygenation (H/R) and adrenergic receptors.

METHODS: Neonatal rat cardiac myocytes were cultured for 20 h after AdCnAalpha transfection, and treated with isoproterenol (10 micromol/L) and 24 h of hypoxia followed by 4 h of reoxygenation (24H/4R). The cardiac myocyte apoptosis induced by the treatments was assessed by flow cytometry and DNA laddering, and the levels of calcineurin, p38 and phosphorylation p38 (p-p38) were determined by Western blotting and (or) RT-PCR.

RESULTS: AdCnAalpha transfection promoted cultured neonatal rat cardiac myocyte apoptosis induced by isoproterenol+24H/4R as compared with the treated cells without transfection (14.247-/+0.525 vs 10.763-/+1.554, P<0.01), along with greater phosphorylation p38 protein expression (1.60-/+0.22 vs 2.42-/+0.19, P<0.01). The levels of p38 underwent no obvious change after AdCnAalpha transfection (P<0.05).

CONCLUSIONS: AdCnAalpha transfection can promote cardiac myocyte apoptosis induced by H/R and adrenergic receptors, the mechanism of which might be associated with p38 mitongen-activated protein kinase (p38MAPK) activation.