Aim To determine the expression of insulin like growth factor 1 receptor (IGF 1R)gene in atherosclerotic plaques. Methods White rabbits were fed with either regular feed or high cholesterol diets for 12 weeks. By in situ hybridization we detected the expression of IGF 1R mRNA in rabbit atherosclerotic plaques and normal artery wall. Results Control rabbits, hybridization with antisense RNA probe only localized IGF 1R mRNA to adventitia. In atherosclerotic aortas, the positive signals were widely distributed in the vessel wall, including neointima, media, adventitia and atherosclerotic plaques. Conclusion Smooth muscle cells, endothelial cells and foam cells are the major source of IGF 1 receptor mRNA in atherosclerotic lesions. Over expression of IGF 1R mRNA might be related to the genesis of the atheromatous plaque. 还原