Expression of transforming growth factor-beta1 and its receptors related to the ureteric fibrosis in a rat model of obstructive uropathy.

Abstract

PURPOSE: Transforming growth factor (TGF-beta) is a multifunctional cytokine that may stimulate fibroblast proliferation and regulate the synthesis of matrix components. To elucidate the role of TGF-beta1 in the process of ureteric fibrosis in obstructive uropathy, we conducted this study. MATERIALS AND METHODS: The expression of TGF-beta1 and TGF-beta receptors I, II, III were studied in 54 rats by the method of immunohistochemistry. RESULTS: The degree of smooth muscle hypertrophy and serosa thickening aggravated gradually along the course of ureteric ligation. The expression of TGF-beta1 in the serosa layer was noticed from day 7 after ligation. The expression of TGF-beta1 and receptors in the serosa layer progressively increased during the period of ureteric obstruction, reached a peak on day 21 after ligation, and then declined. The expression of TGF-beta1 and TGF-beta receptors (II and III) in the serosa layer was correlated significantly (r = 0.8048 and 0.7974, respectively; p values both <0.0001). The expression of TGF-beta1 also correlated significantly with the thickening of serosa layer and the severity of hydroureter (r = 0.6921 and 0.5394, respectively; p values both <0.005). The expression of TGF-beta1 and TGF-beta receptors in the smooth muscle layer was transient and weak, and the expression of TGF-beta1 and TGF-beta receptors was accompanied with the fibrosis in the muscle layer. CONCLUSIONS: We conclude that TGF-beta1 might participate in the progression ofureteric fibrosis in obstructed ureters.