This study was conducted to evaluate the nephroprotective effect of Glycine max seed extract (soybean oil) against gentamicin- and rifampicin-induced nephrotoxicity in Sprague-Dawley rats and to compare its effects with those of vitamin E, which has well-established antioxidant and nephroprotective effects. Sixty male Sprague-Dawley rats (body weight 150-210 g) were divided into 10 groups. The first five groups were treated for 14 consecutive days with normal saline (5 ml/kg, by mouth [p.o.]); gentamicin (80 mg/kg intraperitoneally [i.p.]); gentamicin (80 mg/kg, i.p.) + vitamin E (250 mg/kg p.o.); gentamicin (80 mg/kg i.p.) + soybean oil (2.5 ml/kg p.o.); and gentamicin (80 mg/kg, i.p.) + soybean oil (5 ml/kg p.o.), respectively. For the next five groups, the same group allocation was done, but gentamicin was replaced with rifampicin (1 g/kg i.p.). Various biomarkers for nephrotoxicity in serum and urine were evaluated along with histopathological examination of kidneys. Analysis of variance (ANOVA) was done following Tukey's multiple comparison test; p < .05 was considered significant. Soybean oil in both doses significantly (p < .005) decreased serum blood urea nitrogen, creatinine, urea, uric acid and urine volume, kidney weight, urinary sodium, urinary potassium, and total protein and significantly (p < .005) increased serum total protein and urine creatinine in gentamicin- and rifampicin-treated animals, exhibiting nephroprotective effects. Soybean oil also showed strong antioxidant effects, causing significant (p < .005) increase in kidney homogenate catalases, glutathione peroxidase, and superoxide dismutase and significant (p < .005) decrease in lipid peroxidase in gentamicin- and rifampicin-treated animals. Soybean oil demonstrated good nephroprotective activity due to antioxidant effects.
Keywords: gentamicin; nephrotoxicity; rifampicin; soybean oil; vitamin E.