Abstract
The toxicity of heavy metals such as mercury (Hg) in humans and animals is well documented. The kidney is the primary deposition site of inorganic-Hg and target organ of its toxicity. The present study investigated the protective efficacy of flaxseed lignan-Secoisolariciresinol diglucoside (SDG) on nephrotoxicity induced by mercuric chloride (HgCl2). Rats were intraperitoneally injected with HgCl2 (2 mg/kg/day) and renal toxicity was induced. Subcutaneous administration of rats with SDG (5 mg/kg/day) as a pre-treatment caused a significant reversal of HgCl2 induced increase in blood urea, creatinine, glutathione s-transferase and catalase (CAT). On the other hand, administration of SDG with HgCl2 restored normal levels of albumin and superoxide dismutase (SOD). Histological examination of kidneys confirmed that pre-treatment of SDG before HgCl2 administration significantly reduced its pathological effects. Thus, the results of the present investigation suggest that SDG can significantly reduce renal damage, serum and tissue biochemical profiles caused by HgCl2 induced nephrotoxicity. Hence, SDG may be recommended for clinical trials in the treatment of kidney disorders caused by exposure to Hg.
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Key Points
Mercury is a hazardous heavy metal of industrial and environmental pollutants that affect humans as well as animals, causing severe changes in their tissues. Inorganic-Hg which accumulates mainly in the nephron is bound to cause renal failure. Studies have shown that when Hg-ions are linked with thiol it causes to decreased glutathione (GSH) levels, subsequently elevating the level of reactive oxygen species (ROS). The toxicity of inorganic-Hg leads to oxidative stress and depletion of endogenous thiol.
Whole flaxseed and flaxseed oil diets have been assessed for their effects in a rat renal ablation model, a non-immune model of renal disease, wherein they have significantly decreased symptoms of the disease and showed favourable effects on blood pressure and plasma lipids. The present investigation is focused on the evaluation of the protective efficacy of flaxseed lignan-SDG on HgCl2 induced nephrotoxicity in male Wistar albino rats.
The present investigation showed glomerulus degeneration in response to HgCl2. The present study exhibited comprehensive antioxidant properties of FS lignans SDG. The extracts of SDG given in combination, help in reduction in the Hg-induced nephrotoxicity which reflects the significant increase in the activities of antioxidant enzymes like CAT and GST. Superoxide dismutase catalyzes the superoxide anion radical dismutation into H2O2. Results of the present investigation proved that the supplementation of SDG extracts to the animals treated with HgCl2 significantly restored activities of SOD. SDG, the principal lignan of FS, a di-phenolic compound, may initiate free radical scavenging activity and render protection against HgCl2 induced renal damage. The present study concludes that SDG significantly protects the kidney against HgCl2-induced renal damage by inhibiting the formation of free radicals. Thus, FS and its lignans in food may offer health benefits and disease preventive effects.