Protective effect of insulin on anoxia/reoxygenation-induced apoptosis in cultured cardiomyocyte of neonatal rats

Objective To explore the protective effects and mechanisms of insulin on anoxia/reoxygenation-induced cardiac injury. Methods The model of anoxia/reoxygenation (A/R) injury was extablished through anoxia for 2 hours and reoxygenation for 4 hours in cultured cardiomyocytes of neonatal rats, which were randomized to receive 0.9%Nacl, insulin, LY294002, insulin plus LY294002 at the beginning of reoxygenation. At the end of reoxygenation, activities of lactate dehydrogenase (LDH) and contents of malondialdehyde (MDA) were measured through spectrophotometric procedures.Apoptosis of cardiomyocytes was assessed through TUNEL and DNA Ladder. Western blotting was used to analyse expression of phosphorylated Akt in all groups.Results Compared with Nad group, activities of LDH,contents of MDA,apoptosis index (AI) were significantly decreased, and expression of phosphorylated Akt was markedly increased in insulin-treated group. However those changes of LDH,MDA,AI and phosphorylated Akt were inhibited by LY294002 (PI3K inhibitor). Conclusion The early administration of insulin at reoxygenation could protect cardiomyocytes from anoxia/reoxygenation-induced apoptosis through PI3K/Akt signaling pathway.