Abstract: AIM: To study the effect of fraction F of Naja naja atra venom on proliferation of vascular smooth muscle cells (VSMC). METHODS: The rate of incorporation of [ ³H] thymidine (³H-TdR) into VSMC was observed by cultured VSMC in vitro, and expression of oncogene C-myc and proliferation cell nuclear antigen (PCNA) in VSMC stimulated by 20 % serum was assayed by protein immunoblotting (western blotting). RESULTS: Fration F significantly inhibited the incorporation of³HTdR into VSMCs and the expression of oncogene C-myc and PCNA in VSMC which was stimulated by 20 %serum in a dose-dependent manner.Groups of 30 and 100 mg·L^-1 had obvious difference (P <0.05) when compared with control group. CONCLUSION: Fraction F of Naja naja atra venom inhibits the proliferation of VSMC by affecting expression of oncogene C-myc and PCNA.

Key words: Fraction F of Naja naja atra venom, vascular smooth muscle cells, proliferation, H³-TdR, Cmyc, PCNA, Western blotting