AIMTo study upon to serum deprivation if delta-opioid receptor activation has direct effect on cultured impaired cardiomyocytes survival.

METHODSMyocardial cells of neonatal rats were cultured in vitro. The cell viability was determined with crystal violet staining uptake. The percentage of S + G2 + M in cell cycle was determined by flow cytometry. Apoptosis rates were determined by flow cytometry (FCM). The expression of Caspase-3 were investigated by Western blotting.

RESULTSMyocardial cells of neonatal rats were cultured of serum-free in vitro, apoptotic index was significantly increased, the expression of Caspase-3 was significantly increased, free-serum induced apoptosis in cardiac myocytes after 48 h. At concentrations of 10 nmol x L(-1) - 10 micromol x L(-1), a delta opoid receptor agonist [D-Ala2, D-Leu5]-enkephalin DADLE promoted the myocardial cells survival, in a concentration-dependent manner. The optimal response was achieved at 0.1 micromol x L(-1), which increase survival index of cardiac myocyte, percentage of S + G2 + M in cell cycle, decrease apoptotic index of cardiac myocyte, and the expression activate caspase-3. Delta-opioid receptor antagonist naltrindole at 10 micromol x L(-1) inhibited the promoting effects of DADLE, which decrease survival index of cardiac myocyte, and percentage of S + G2 + M in cell cycle, increase apoptotic index of cardiac myocyte and the expression of Caspase-3.

CONCLUSIONThe protective of delta-opioid receptor activation can promote survival in cultured impaired myocardial cells.