Renoprotection of Kolaviron against benzo (A) pyrene-induced renal toxicity in rats

Benzo(a)pyrene (B[a]P), a polycyclic aromatic hydrocarbon generally formed from incomplete combustion of organic matter, reportedly causes renal injury and elicits a nephropathic response. The present study investigated the modulatory effect of Kolaviron, an isolated bioflavonoid from the seed of Garcinia kola, on renal toxicity induced by B[a]P in Wistar rats. Benzo[a]pyrene was administered at a dose of 10 mg/kg alone or in combination with Kolaviron at 100 and 200 mg/kg for 15 d. Administration of B[a]P alone resulted in significant increase in plasma levels of urea and creatinine in the treated rats. Moreover, B[a]P exposure significantly decreased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-s-transferase (GST) as well as glutathione (GSH) level in the kidneys of treated rats. Conversely, myeloperoxidase (MPO) activity, hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels were markedly elevated in kidneys of B[a]P-treated rats compared with control. Further, B[a]P exposure significantly decreased the circulatory concentrations of triiodothyronine (T3) and T3/T4 ratio without affecting thyroxine (T4) in the treated rats. Light microscopy revealed tubular lumen with numerous protein casts in kidneys of rats exposed to B[a]P alone. Kolaviron co-treatment significantly improved the renal antioxidant status, thyroid gland function and restored the renal histology, thus demonstrating the protective effect of Kolaviron in B[a]P-treated rats. Dietary inclusion of Kolaviron could exert protective effects against renal toxicity resulting from B[a]P exposure.