Abstract: AIM To investigate the expression of monocyte chemotactic protein-induced protein( MCPIP) in the process of atherosclerosis in rats. METHODS Sixty Sprague Dawley rats were randomly divided into four model groups and four control groups. Atherosclerosis was established by feeding rats with a high-fat diet and gavage of vitamin D3 for 2,4,6 and 7 weeks,respectively. Control rats were fed with a normal diet. The pathological changes of thoracic aorta were observed by HE staining.mRNA levels of MCPIP in thoracic aorta were determined by real time-PCR and MCPIP protein was detected by immunohistochemistry. RESULTS Pathological examination showed that atherosclerotic lesions occurred 2 weeks after treatment and progressed with time. Real-time PCR results showed that vascular MCPIP mRNA increased in model rats compared with that in controls( P < 0. 05 or P < 0. 01).Immunohistochemistry showed increased expression of MCPIP protein with time. Expression of MCPIP protein in four model groups were significantly higher than in the corresponding normal control groups( P <0. 05 or P <0. 01). CONCLUSION We successfully established atherosclerosis in rats by feeding a high-fat diet plus vitami D3. Thoracic aortic atherosclerotic lesions occur 2 weeks after treatment and gradually are aggravated. Expressions of vascular MCPIP mRNA and protein increase after treatment,suggesting that MCPIP plays an important role in the development of atherosclerotic lesions.