Ameliorative role of curcumin and ascorbic acid on nephrotoxicity induced by environmentally relevant concentrations of different combinations of lead, fluoride and nitrate in albino rats

Groundwater pollution with lead, fluoride, and nitrate presents a growing environmental and health challenge. This study aimed to evaluate the nephrotoxic effects of these pollutants in male albino rats and assess the potential ameliorative effects of curcumin and ascorbic acid in counteracting their toxicity for 135 days. A total of ten treatment groups were established viz. control, lead + fluoride + nitrate (BIS), lead + nitrate, lead + nitrate + curcumin + ascorbic acid, lead + fluoride, lead + fluoride + curcumin + ascorbic acid, fluoride + nitrate, fluoride + nitrate + curcumin + ascorbic acid, lead + fluoride + nitrate, lead + fluoride + nitrate + curcumin + ascorbic acid. Exposure to lead, fluoride, and nitrate resulted in a significant decrease in the activity of oxidative stress enzymes viz. superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase, and a notable increase in the lipid peroxidation levels. Further, significantly increased urea and creatinine levels in plasma and renal damage including glomerular shrinkage, widened Bowman's space, and tubular degeneration were also observed. The greatest damage was recorded in the lead + fluoride + nitrate group followed by lead + fluoride, lead + nitrate, and fluoride + nitrate. Co-treatment with curcumin and ascorbic acid demonstrated remarkable protective effects, with improvements in oxidative stress markers, plasma urea, and creatinine levels along with a significant restoration of glomerular structure and normalization of Bowman's space reflecting improved renal function. This research highlights the kidneys' susceptibility to environmental toxicants and the combined efficacy of curcumin and ascorbic acid in mitigating nephrotoxicity.