Abstract: Objective To study the effect of interferon alpha (IFN-α) on vascular smooth muscle cells (VSMCs) apoptosis 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 expression of P204 and P21 mRNA was determined by semiquantitative RT-PCR. P204 and P21 protein was analyzed by Western blotting. The cell apoptosis was analyzed by flow cytometry with Annexin-V FITC/PI method. Results Compared with control group, in IFN-αinduction group, the expression of P204 mRNA and protein was up-regulated(P＜0.01), the cell apoptosis was increased (P＜0.01), and the expression of P21 mRNA and protein was up-regulated (P＜0.01). In IFI204 transfection group, the expression of P204 mRNA and protein was down-regulated(P＜0.01), the cell apoptosis was decreased (P＜0.01), and the expression of P21 mRNA and protein was down-regulated (P＜0.01). When intervention with IFN-α after transfection IFI204 siRNA, the expression of P204 mRNA and protein was down-regulated (P＜0.01), but the expression of P21 mRNA and protein were not decreased correspondingly(P＜0.01), and cell apoptosis was increased (P＜0.01), Conclusion P204 and P21 participation in interferon-α regulation of cell apoptosis of vascular smooth muscle cells in rats.

Key words: interferon, vascular smooth muscle cells, apoptosis, interferon-inducible protein, P204