Abstract: Objective To study the action of RAS signaling pathway in interferon alpha (IFN-α) inhibition proliferation of vascular smooth muscle cells (VSMCs) in rats. Methods Cultured VSMCs were treated with transfection IFI204 siRNA and/or IFN-αin vitro instantaneously. Nonspecific siRNA transfection group was as control group. The cell vitality was detected by MTT method, and the cell cycle was analyzed by flow cytometry. The expression of P204 mRNA was determined by semiquantitative RT-PCR. P204, RAS protein and the phosphorylation levels of RAF and ERK was analyzed by Western blotting. Results Compared with control group, the expression of P204 mRNA and protein up-regulated(P＜0.01), the cell vitality and the cell cycle of G1/S transition down-regulated(P＜0.01). In the process of the above, the expression of RAS protein decreased(P＜0.01) and the phosphorylation levels of RAF and ERK droped(P＜0.01); When intervention with IFN-α after transfection IFI204 siRNA, down-regulated the expression of P204 mRNA and protein(P＜0.01), and cells of G0/G1 stage increased and S stage decreased(P＜0.01), but the expression of RAS protein and the phosphorylation levels of RAF and ERK did not increase correspondingly(P＜0.01). Conclusion RAS signal pathway participation in interferon-α inhibition of proliferation of vascular smooth muscle cells in rats.

Key words: Interferon, Vascular smooth muscle cells, Proliferation, Interferon-inducible protein, P204, RAS signaling pathway