ABSTRACT
OBJECTIVE: To investigate the effect of diet-induced hyperlipidemia on TGF-beta/Smad signaling pathway in the kidney of diabetic rats, and to explore the mechanism by which hyperlipidemia leads to renal injury in diabetes. METHODS: Diabetic rats and non-diabetic rats were fed with normal fat diet and high fat diet for 16 weeks, respectively. The expressions of TGF-beta1, TbetaRII, and Col-IV mRNA in the renal cortex were examined by reverse transcriptase-PCR,TbetaRII and p-Smad staining in glomerular cells were detected by immunohistochemical staining, and the expression of TGF-beta1 and Col-IV protein was determined by Western blot. RESULTS: Diet-induced hyperlipidemia up-regulated the levels of TGF-beta1, TbetaRII, p-Smad, and Col-IV protein and mRNA in the renal cortex of diabetic rats compared with those of non-diabetic rats. However, feeding high fat diet to non-diabetic rats had no influence on the expression of TGF-beta1, TbetaRII, p-Smad2, and Col-IV in the renal cortex. CONCLUSION: Hyperlipidemia induced by high fat diet ingestion leads to renal injury in diabetic rats through activating TGF-beta1 /Smad signaling pathway.
