Effect of zinc supplementation on chronic hepatorenal toxicity following oral exposure to glyphosate-based herbicide (Bushfire®) in rats

Objectives To assess the effects of zinc pretreatment on hepatorenal toxicity following chronic exposure to glyphosate-based herbicides in male rats. Methods Following zinc pretreatment (50 mg/kg and 100 mg/kg), 14.4 to 750 mg/kg of oral glyphosate (Bushfire® herbicide) was administered daily for 36 weeks. Thereafter, serum samples were obtained following jugular venipuncture. Liver and kidney samples were processed for histopathological examination. Results Serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase activity as well as levels of bicarbonate, calcium, creatinine were significantly increased following chronic exposure to Bushfire®. Serum levels of sodium, potassium, chloride, total protein, albumin, globulin and urea were unchanged. Moderate to severe coagulative necrosis of hepatocytes as well as glomerular and renal tubular necrosis were observed in herbicide-treated rats. Zinc pretreatment reduced the elevation of serum enzymes associated with hepatobiliary lesions, abrogated hypercalcemia and metabolic alkalosis, and mitigated serum accumulation of creatinine following Bushfire® exposure, but was ineffective in completely preventing histological lesions. Conclusion Chronic Bushfire® exposure in rats caused hepatorenal toxicity. The effects of exposure on serum parameters were ameliorated by zinc pretreatment, but the histopathological changes associated with toxicity persisted in milder forms in zinc-pretreated animals.