The role of eNOS on the regulatory effects of EPO on mitochondrial biogenesis in cardiomyocytes exposed to chronic hypoxia / 重庆医学

ABSTRACT

Objective To explore the role of endothelial nitric oxide synthase(eNOS) in the regulatory effects of erythropoie‐tin (EPO) on mitochondiral biogenesis in cardiomyocytes exposed to chronic hypoxia .Methods H9c2 cardiomyocytes were cultured in the environment of hypoxia for 1 week(94% N2 ,5% O2 ) ,establishing the chronic hypoxic cardiomyocyte model .All the cells were divided into 3 groupsHC(chronic hypoxic control) ,HE[treated with chronic hypoxia and 20 U/mL recombinant human EPO (rhEPO) ]and HR(cells transfected with eNOS shRNA plasmid and treated with 20 U/mL rhEPO and chronic hypoxia) .Fluores‐cent probe was used to detect the changes of mitochondial number .Mitochondial DNA (mtDNA) relative express level was assayed by RT‐PCR .The expression and phosphorylation of eNOS protein were analyzed with Western blot .Results rhEPO significantly increased the phosphorylation of eNOS and elavated the mitochondialt number and mtDNA (P< 0 .05) .shRNA interference on eNOS significantly blocked all the above changes induced by rhEPO (P<0 .05) .Conclusion Phosphory lation of eNOS is the im‐portant signalling pathway for the enhanced mitochondrial biogenesis in cardiomyocytes exposed to chronic hypoxia by EPO .