TGF-β1 Effects on Total Collagen of the New Zealand Rabbit's Urethral Wall (Oryctolagus cuniculus) in Animal Models of Urethral Stricture.

Abstract

Currently, animal models of urethral stricture are not standardized. Transforming Growth Factor Beta 1 (TGF-β1) regulates extracellular matrix deposition in homeostatic and pathological responses. The aim of this study was to present the potential model to be developed as a urethral stricture. True experimental laboratory research was conducted by using Male New Zealand rabbits (Oryctolagus cuniculus), which were divided into 5 groups; control, placebo, and 3 treatment groups (TGF-β1 injection of 1 µg, 2 µg, 4 µg). Urethrography, histopathological analysis, and evaluation of total collagen formation of the urethral wall were performed after 6 weeks. An increase in the dose of TGF-β1 decreased the mean rabbit's urethral lumen diameter (29.3% in the 2µg group and 34% in the 4µg group) compared to controls. Three rabbits decreased as much as ≤ 50% in urethral lumen diameter. Significant increases in total collagen density in the periluminal and peripheral urethral spongiosum were noted by increasing doses of TGF-β1. The percentage of urethral lumen diameter has a strong negative correlation with periluminal total collagen density (r = -0,798; p = 0,000) and very strong negative correlation with peripheral spongiosa total collagen density (r = -0,748, p = 0,000). TGF-β1 plays a role in changing total collagen compositions of the rabbit's urethral wall, decreasing the urethral lumen diameter. Further research with increasing doses of TGF-β1 is needed to determine the effective dose of TGF-β1 in inducing urethral stricture.