Abstract: Objective:To explore the effect of differentiation of cardiac stem cells(CSC) mediated by pilose antler polypeptides on the expressions of terminal myocardial differentiation genes atrial natriuretic polypeptide(ANP) and myosin light chain 2v(MLC-2v),and to clarify the mechanism of repairing the damaged myocardium. Methods: The healthy male Wistar rats born 2 d were selected to extract the CSC.The surface marker c-Kit and the purity of CSC were identified by immunofluorescence and flow cytometry.The culture dish was used as the experimental unit and the extracted cells were divided into the following four groups:blank control group (the same amount of buffer was added for induction),5-azacytidine group(induced with 3 μmol·L^-1 5-azacytidine),pilose antler polypeptides group(induced with 800 mg·L^-1 pilose antler polypeptides) and combined group(induced with 800 mg·L^-1 pilose antler polypeptides and 3 μmol·L^-1 5-azacytidine);the cells were incubated for 48 h in the condition of 37℃ and 5% CO₂.The expression levels of ANP and MLC-2v in supernatant of the cells in various groups were detected by ELISA method.The expression levels of ANP and MLC-2v mRNA in the cells in various groups were detected by RT-PCR method. Results: CSC were prepared with the purity>95%.The results of ELISA showed that the expression levels of ANP and MLC-2v in 5-azacytidine, pilose antler polypeptides and combined groups were significantly increased compared with blank control group(P<0.05).The expression levels of ANP and MLC-2v in combined group were increased compared 5-azacytidine and pilose antler polypeptides groups,but there were no significant differences(P>0.05).The result of RT-PCR showed that the expression levels of ANP and MLC-2v mRNA in 5-azacytidine,pilose antler polypeptides and combined groups were significantly increased compared with blank control group(P<0.05). Conclusion: Pilose antler polypeptides can induce the differentiation of CSC into cardiac cells by promoting the expressions of ANP and MLC-2v, and they can reduce the cytotoxicity induced by 5-azacytidine in some degrees.

Key words: pilose antler polypeptides, myosin light chain 2v, cardiac stem cells, atrial natriuretic polypeptide