Effect of simvastatin on expression of integrin-linked kinase and renal tubulointerstitium injury in rats induced by high fat diet

AIM: To explore the effect of simvastatin on expression of integrin-linked kinase (ILK) and the injury of renal tubulointerstitium in the rats induced by high fat diet. METHODS: Fifty-four 6-8 week-old female Wistar rats were randomly assigned to the following three groups: high fat diet group, simvastatin group (rats were fed with high fat diet plus 10 mg·kg-1·d-1 simvastatin) and control group. Six rats in each group were sacrificed at 4th week, 10th week, and the others at 20th week. The injury of renal tubulointerstitium was observed under microscope with HE staining and the expression of renal ILK was determined by Western blotting analysis and immunohistochemistry. Levels of total cholesterol (TC) and triglyceride (TG) in serum were measured by enzymatic colormetric methods. RESULTS: The serum TC and TG levels and the expression of renal ILK significantly increased in both high-fat diet group and simvastatin group, compared to control group at 4th week, reaching a maximum at 20th week (P<0.01). Tubulointerstitium injuries including vacuolar degeneration, syncytial change, clody swelling, necrosis and atrophy of renal tubular epithelial cells, thinning of tubal wall, lumens compensational expansion or even abolition, and inflammatory cell infiltration, interstitial fibrosis were found in both high fat diet group and simvastatin group, compared to control group at 4th week, worsened to a maximum at 20th week. However, all of these ameliorated in simvastatin group, compared to high fat diet group at each time point. CONCLUSION: The results indicate that high-fat diet induces significant lesion of renal tubulointerstitium and increased expression of renal ILK. Simvastatin may play an important role in protecting against tubulointerstitium injury induced by hyperlipoidemia by down-regulating the expression of renal ILK.