ABSTRACT
AIM: To study the effect of high fat diet on the expression of sterol regulatory element biding protein-1 (SREBP-1) and transforming growth factor β_1 (TGF-β_1) in renal tubular cells and rosiglitazone intervention. METHODS: Wistar rats were treated with high fat diet and rosiglitazone for 3 months. The serum glucose, serum insulin and serum triglyceride were detected. Oil Red O staining was used to observe the renal lipid deposit and Masson staining was for the detection of ECM accumulation. SREBP-1, TGF-β_1 and FN protein were determined by the methods of immunohistochemistry and Western blotting. SREBP-1 mRNA was detected by in situ hybridization. RESULTS: Rosiglitazone prevented effectively the increase in serum glucose, serum insulin and serum triglyceride resulted from high fat diet. High fat diet led to lipid droplet formation in renal tubular cells and interstitial ECM accumulation, which was decreased by rosiglitazone treatment. Compared to normal rats, SREBP-1 protein and SREBP-1 mRNA showed high expressions in high fat diet rats that were lowered by rosiglitazone. The precursor segment and mature segment of SREBP-1 protein were decreased by 27.39% and 27.32%. Similarly, the high expressions of TGF-β_1 and FN protein in kidney of high fat diet rats were also prevented by rosiglitazone intervention. Compared to high fat diet rats, the expression of TGF-β_1 in rosiglitazone treatment rats was lowered by 19.14%. CONCLUSION: Rosiglitazone prevents effectively the over-expression of SREBP-1 and TGF-β_1 in renal tubular cells, and decreases lipid accumulation and ECM production in rats fed with high fat diet.