ORIGINAL ABSTRACT

There have been major concerns that the nephrotoxicity of commercial formulations of Roundup herbicide is due to the active ingredient glyphosate. We therefore investigated and compared the mechanisms underlining the nephrotoxicity of Roundup herbicide and glyphosate alone in rat. Fifty-six adult male rats randomized into 7 groups of 8 rats per group were exposed to Roundup formulation and glyphosate alone daily by gavage at 3.6, 50.4, and 248.4 mg/kg body weight (bw) of glyphosate concentrations for 12 weeks with distilled water administered to the control group. Kidney biomarker (serum urea and creatinine, plasma cystatin-C, and neutrophil gelatinase-associated lipocalin), oxidative stress indices in the kidney tissue, activities of kidney membrane-bound enzymes (Mg-adenosine triphosphatase [ATPase], Ca-ATPase, Na/K-ATPase, and total ATPase), and histopathological changes in the kidney were monitored. Glyphosate concentration in the kidney was quantified by high-performance liquid chromatography with ultraviolet detection. Significant ( P < 0.05) alterations in the levels of the kidney biomarker, oxidative stress markers, and membrane-bound enzymes were observed in the rats exposed to Roundup compared to the rats exposed to glyphosate alone. Rats exposed to Roundup accumulated more glyphosate residue in their kidney tissue. Severe histopathological lesions were only seen in the kidneys of rats exposed to Roundup. The nephrotoxicity observed cannot be due to the active ingredient in the Roundup formulation, as glyphosate alone has virtually no effect on the renal function of the exposed animals. Therefore, the general claim attributing nephrotoxicity of a glyphosate-based herbicide to its active ingredient should be discouraged.