Objective To study the expression character of CKMB and cTnI presented in long-time in vitro hypoxic myocardial cells,and provide theoretical consult in understanding the mechanism of highly expressing CKMB and cTnI induced by hypoxia in hearts.Methods The myocardial cells were sampled from newborn Wister mice.Two-step RT-PCR and Western Blotting were applied to detect the consecutive expression variation of HIF-1α and CKMB.cTnI both in the supernatant and inner of incubating cells after 40-minute hypoxia intervention.Results There had CKMB appeared in the supernatant within 15min after hypoxic stimulation.with slow increasing along the time.The intracellular CKMB expression got its peak point within 1h,and then descended.1k intracellular CKMB concentration was significantly higher than that of the supernatant of hypoxic myocardial cells within Omin-24h(P<0.05).The cTnI concentration of supematant steeply increased after 1 5min,reaching the peak point within 24h.The intracellular cTnI concentration reached the peaK point within 45min.The significant differences always existed for the cTnI expression between intra-and extra-myocardial cells within 15min-48h(P<0.05),and their increasing tendencies nearly showed synchronism.The intracellular cTnI concentration was lower than that of supernatant 24h later.Conclusion The single persistent hypoxic stimulation could induce the intensive intracellular expression and delivery of CKMB and cTnI in vitro myocardial cells.and the latter probably was caused by the leakage of cell membrane originally provoked by hypoxia.