Toxicological Outcome of Combined Exposure to Potassium Dichromate and Levonorgestrel in the Kidney of Female Rats

Co-exposure to chromate (VI) compound and oral contraceptives is common in our environment especially among women working in chromate-related industries. Exposure to either chromate (VI) or oral contraceptives is linked with the etiology of several diseases including cancers and renal injury. However, there is paucity of information on the toxic effect of combined co-exposure to both compounds. The present study examines the toxicity of combined exposure to potassium dichromate (PDC) and an oral contraceptive, levonorgestrel in the kidney of female rats. Control animals were fed distilled water, while experimental rats were injected 12 mg/kg body weight of PDC once a week for six weeks and oral daily exposure to 15µg/kg body weight of levonorgestrel either alone or in combination. Absolute and relative kidney weight, renal function, oxidative stress and pathological lesion were assessed in plasma and kidney of control and experimental rats. The PDC and levonorgestrel significantly (p<0.05) increased plasma urea creatinine and malondialdehyde levels in treated-rats, while renal superoxide dismutase and glutathione-S-transferase activities were reduced by both compounds. Moreover, histopathological lesions including necrotizing nephritis was observed in the kidney of PDC-treated rats, while tubular epithelial degeneration and necrosis was observed in levonorgestrel-treated rats. Combined exposure to both compounds aggravated the increase in urea, creatinine and renal damage. Additionally, the antioxidant enzymes were further repressed in the co-treatment group. The study suggests that combined exposure to potassium dichromate and levonorgestrel worsened nephrotoxicity in rats by increasing oxidative stress.