Abstract: Objective To study the regulation mechanism of hypoxia-inducible factor-1α（HIF-1α）in rat myocardium cell under hypoxia environment. Methods Small interference RNA （siRNA） targeing HIF-1α was constructed and transfected into rat myocardium cell lines(H9C2).The HIF-1α and cardiotrophin-1（CT-1 ）gene expression at mRNA levels were detected by real-time PCR. The HIF-1α and CT-1 gene expression at protein levels were detected by western blot. Results Expression of the mRNA and protein level of HIF-1α and CT-1 were down regulated after silencing of HIF-1α under hypoxia environment(P<0.05). Expression of the protein level of HIF-1α and the mRNA and protein level of CT-1 increased after exposure of untransfected H9C2 cells to hypoxia(P<0.05). Expression of the protein level of CT-1 increased from 0.34±0.05 to 0.55±0.05(P<0.05).Conclusion The regulation of CT-1 gene under hypoxia could be activated by HIF-1α that plays an important role in myocardial adaptation to hypoxia.

Key words: small interference RNA, hypoxia-inducible factor-1α, cardiotrophin-1, myocardium under hypoxia environment.