DNA Microarray Analysis And Cathepsin D Expression Of Aorta Tissue From Rats With Atherosclerosis

AIM: To explore the potential candidate genes related to extracellular matrix(ECM),especially cathepsin D, which might play roles in atherosclerosis (AS) pathogenesis by microarray technology.METHODS: (1)Male SD rats were fed with fat diet (containing 3% cholesterol, 0.5% sodium cholate, 5% refined sugar, 10% lard, and 81.5% base feed) and injected with vitamin D3 i.p. to establish the experiment atherosclerotic model.(2)After 14 weeks, total cholesterol (TC) and triglyeride (TG) in serum were detected. Aorta and coronary arteries were stained with HE and a solution of oil red O to visualize the lesion area.(3)Total RNA was isolated from the aorta for microarray to explore the differential gene expression profiling.(4)Cathepsin D expression was measured by immunofluorescence and western-blot.RESULTS: (1)Compared with the control group, model group showed elevated TC and TG in serum (both P<0.01), and obvious aortic fibrous plaques. (2)Of the 20500 genes explored,1218 genes were downregulated and 510 genes were upregulated. The differential expression genes were associated with inflammation, lipid metabolism, oxidative stress and cell apoptosis. The upregulated genes related to ECM remodeling included thrombospondin, osteopontin, perlecan, MMP-11, CathepsinB, CathepsinL, CathepsinD, CathepsinY, cytokines and inflammatory factors(TNF-α) etc. The downregulated ones included growth factor(TGF-β), CystatinC, MMp-2, MMp-16, MMp-23 and serine protease inhibitor, serine protease inhibitor (serpin).(3)Immunofluorescence analysis showed that cathepsin D was mainly localized in the intima and tunica media, especially in the thicken tunica media. Further western-blot revealed that Cathepsin D protein expression was significantly increased in aorta of model group compared with control group. CONCLUSION: (1)Combining the high fat/cholesterol diets with injection of vitamin D3 successfully established the experiment atherosclerotic model in rats. (2)AS was a complex disorder resulting from a network of gene–gene and gene–environment interactions, the pathogenesis of AS was in close relation with ECM. Cathepsin D might play an important role in AS.