AimTo Study the basic expression of the interferon-inducible protein p204 in murine vessel wall cells, and the characteristic induced by interferon (IFN).MethodsWe used immunohistochemistry and Western blot to observe the expression of protein p204 in adult Kunming (KM) mice and Wistar rat or SD rat vessel wall, through immunocytochemistry and Western blot observation studied the expression and distribution of p204 in cultured vascular smooth muscle cells (VSMC) and vascular adventitia fibroblasts (VAF) which was isolated from SD rat aorta, and used reverse transcription polymerase chain reaction (RT-PCR) to detect the characteristic of IFN-α induced interferon induced protein 204 (Ifi204) mRNA expression.ResultsImmunohistochemistry showed that p204 antigen stain were positive in vascular endothelial cells (VEC), intima, media and adventitia of intracardiac venules and arterioles vessel wall; p204 stain were positive in adult Wistar rat aortic endothelium, VSMC, adventitia, and negative in elastic fiber membrane.Western blot indicated the basic expression of p204 in SD rat aorta, and the VAF p204 basic expression was obviously higher than VSMC.Immunocytochemistry showed that p204 were present in the cytoplasm and also nucleus of VSMC.Ap- plication of IFNα with the terminal concentration of 10×106 IU/L stimulated VSMC cell for 8 hours, that is to say, induced the significant expression of Ifi204 mRNA,then it expressed more intense when stimulated for 24 hours.ConclusionsThere are basic expressions of p204 in full vessel wall of mice or rat and cultured rat VSMC or VAF.p204 expression is not limited to the nucleus and IFNα can induce the Ifi204 mRNA expression increased in VSMC.p204 expression in murine vessel wall cells suggests its potential and important role in vascular physiology and also in the occurrence and development of vascular proliferation diseases.