The protective effect of taurine against gentamicin-induced acute tubular necrosis in rats

Background. Taurine, which is the major intracellular free beta-amino acid, is known to be an endogenous antioxidant and a membrane-stabilizing agent. In this study, we wished to know whether taurine altered the concentration of gentamicin in kidney tissue and could protect against gentamicin-induce d acute proximal tubular injury. Methods. Wistar albino rats of both sexes were assigned to three groups, wh ich all received one of the following daily intraperitoneal injections for 8 days: (i) 0.9% sodium chloride (NaCl) alone at the same volume as gentami cin treated rats (group C; n=8); (ii) 100 mg/kg/day gentamicin alone (group G; n=8, four male, four female); or (iii) 100 mg/kg/day gentamicin plus 7. 5 ml/kg/day taurine (group GST; n=9, five male, four female). Urine was col lected for 24 h for the determination of urine volume and creatinine. Intra cardiac blood was collected for blood urea nitrogen (BUN) and serum creatin ine determination. The kidneys were removed, weighed, and the left kidneys were subjected to biochemical analysis for the determination of thiobarbitu ric acid-reactive substance (TBARS) and lactate levels, and glutathione per oxidase (Gpx) and superoxide dismutase (SOD) activities. The right kidneys were divided vertically in half. The upper halves were used for histopathol ogical examination, by light and electron microscopy. The lower halves were used to detect the gentamicin concentration within the kidney tissue, by h igh-performance liquid chromatography (HPLC). Changes in body weight and no rmalized kidney weight were recorded. Results. Taurine treatment reduced gentamicin-induced increases in serum cr eatinine, 24 h urine volume, BUN and tissue lactate and TEARS levels (0.57/-0.02 vs 1.06+/-0.08 mg/dl, P<0.001; 9.00+/-1.46 vs 20.9+/-2.73 ml, P<0.00 1; 25.3+/-1.87 vs 54.1+/-6.99 mg/dl, P<0.001; 2.56+/-0.10 vs 3.44+/-0.08 mu mol/g wet tissue, P<0.001; and 66.4+/-3.41 vs 79.5+/-5.07 nmol/g wet tissu e, P>0.05, respectively). Taurine reduced the accumulation of gentamicin wi thin the kidney tissue (233+/-29 vs 494+/-93 mu g/g wet tissue, P<0.05). Ta urine treatment also prevented body weight loss due to gentamicin administr ation (17.8+/-1.64 vs -10.0+/-7.08 g, P<0.01) and normalized reduced Gpx an d SOD activities (3.46+/-0.16 vs 2.37+/-0.15 U/g wet tissue, P<0.01; and 15 577+/-377 vs 12662+/-577 U/g wet tissue, P<0.01, respectively). Light micro scopic examination of the renal tissues from gentamicin-treated rats reveal ed severe histopathological changes, whereas specimens obtained from taurin e-treated rats revealed only mild changes. This finding was supported by el ectron microscopic examination. Conclusions. Our observations suggest that taurine treatment attenuates the accumulation of gentamicin within kidney tissue and counteracts the delete rious effect of gentamicin on renal tubular function. They may have potenti ally important clinical implications.