[Expression of plasma thrombospondin-1 in renal interstitial fibrosis].

OBJECTIVE: To observe the expression of plasma thrombospondin-1(TSP-1) at different time in protein-overload rats and to analyze the relationship between plasma TSP-1 expression and renal interstitial fibrosis. METHODS: Forty-five male Sprague-Dawley rats were randomly divided into a bovine serum albumin (BSA) group and a control group after uninephrectomization. Rats with protein overload nephropathy induced by intraperitoneally injected BSA were used as a model (control group received saline). At the 1st, 5th, and 9th weekend, the level of 24 h proteinuria and renal function was assessed. Pathological changes were observed by electron and fluorescent microscopy. The expression of plasma TSP-1 was detected by Western blot. The relationship between plasma TSP-1 and tubulointerstitial lesions (TIL) score was analyzed. RESULTS: Twenty-four hour proteinuria and blood urea nitrogen (BUN) significantly increased in protein-overload rats compared with those in the control group. While protein-overload rats developed more severe fibrosis in the tubular and interstitium. Glomerulosclerosis index and TIL score were upregulated compared with those in the control group. The expression of TSP-1 increased significantly at the 5th and 9th weekend. The expression of TSP-1 was positively correlated with TIL score (r=0.836, P<0.01). CONCLUSION: Plasma TSP-1 expression is positively correlated with renal interstitial fibrosis in protein-overload rats. Plasma TSP-1 may be used for an important biomarker of renal interstitial fibrosis.