The present study was designed to evaluate the protective effects of hesperidin, a flavonoid on DEN initiated and Fe-NTA promoted renal carcinogenesis in Wistar rats. Renal cancer was initiated by a single i.p. injection of DEN (200 mg/kg b.wt.) and promoted with Fe-NTA (9 mg Fe/kg b.wt. i.p.) twice a week for 16 weeks. Rats were simultaneously administered with hesperidin (100 and 200 mg/kg b.wt.) for 16 consecutive weeks. The chemopreventive effect of hesperidin was assessed in terms of antioxidant activities, renal function, PGE2 level, and the expressions of COX-2 and VEGF. Hesperidin decreased the DEN and Fe-NTA induced lipid peroxidation, improved the renal function (by decreasing the levels of BUN, creatinine, and KIM-1) and restored the renal antioxidant armory (GSH, GPx, GR, SOD, and catalase). Hesperidin was also found to decrease the level of PGE2 and downregulate the expressions of COX-2 and VEGF. Histological findings further revealed the protective effects of hesperidin against DEN and Fe-NTA induced kidney damage. The result of our present findings suggest that hesperidin may be a promising modulator in preventing renal cancer possibly by virtue of its ability to alleviate oxidative stress and inhibit COX-2/PGE2 pathway.

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Mercury, a heavy metal, is widespread and persistent in the environment and has been elucidated as a possible risk factor in cardiovascular diseases. Mercury has been reported to selectively impair the nitric oxide (NO) pathway in the vascular endothelium as a consequence of oxidative stress. Conversely, mercury per se causes endothelium-dependent vasorelaxation at lower concentration via the NO pathway. Little is known about the effects of mercury per se on other endothelial mediators. To elucidate possible mechanisms involved in this action, isometric tension was measured in aortic rings precontracted with phenylephrine (10 µM) from Wistar rats. Responses to increasing concentrations of inorganic mercuric chloride (10−12–10−5 M) were obtained in the presence and absence of endothelium. Inorganic mercury produced a biphasic response in endothelium-intact aortic rings and produced only vasoconstriction in endothelium-denuded aortic rings. To study the possible underlying mechanisms for the biphasic response of mercury, increasing concentrations of mercuric chloride (10−12–10−5 M) were used before and after NG-nitro-l-arginine methyl ester (L-NAME (10−4 M)), glybenclamide (10−5 M), superoxide dismutase (10 U/ml) + catalase (100 U/ml), and nifedipine (10−4 M) treatment. Results suggest that mercury produces endothelium-dependent relaxation at low concentration mediated by endothelial-generated NO and endothelium-derived hyperpolarizing factor and endothelium-independent contraction resulting from the blockade of l-type Ca2+ channels by generation of free radicals.

Trichloroethylene (TCE), a nephrotoxicant is known to cause severe damage to the kidney. In this study, the nephroprotective potential of hesperidin was evaluated against TCE-induced nephrotoxicity in wistar rats. Oral administration of TCE (1000 mg/kg b.wt) for 15 days enhanced renal lipid peroxidation and reduced antioxidant enzymes armoury viz., reduced renal glutathione, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, catalase and superoxide dismutase. It also enhanced the levels of blood urea nitrogen, creatinine and kidney injury molecule (KIM-1). Caspase-3 and bax expression were found to be elevated, while that of bcl-2 reduced suggesting that TCE induces apoptosis. However, pretreatment with hesperidin at a dose of 100 and 200 mg/kg b.wt for 15 days significantly decreased lipid peroxidation, increased the levels of antioxidant enzymes and reduced blood urea, creatinine and KIM-1 levels. Hesperidin also modulated the apoptotic pathways by altering the expressions of caspase-3, bax and bcl-2 to normal. Our results suggest that hesperidin can be used as a nephroprotective agent against TCE-induced nephrotoxicity.

Mercury exposure induces endothelial dysfunction leading to loss of endothelium-dependent vasorelaxation due to decreased nitric oxide (NO) bioavailability via increased oxidative stress. Our aim was to investigate whether acute treatment with methyl mercury chloride changes the endothelium-dependent vasodilator response and to explore the possible mechanisms behind the observed effects. Wistar rats were treated with methyl mercury chloride (5 mg/kg, po.). The methyl mercury chloride treatment resulted in an increased aortic vasorelaxant response to acetylcholine (ACh). In methyl-mercury-chloride-exposed rats, the % change in vasorelaxant response of ACh in presence of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME; 10−4 M) was significantly increased, and in presence of glybenclamide (10−5 M), the response was similar to that of untreated rats, indicating the involvement of NO and not of endothelium-derived hyperpolarizing factor (EDHF). In addition, superoxide dismutase (SOD) + catalase treatment increased the NO modulation of vasodilator response in methyl-mercury-chloride-exposed rats. Our results demonstrate an increase in the vascular reactivity to ACh in aorta of rats acutely exposed to methyl mercury chloride. Methyl mercury chloride induces nitric oxide synthase (NOS) and increases the NO production along with inducing oxidative stress without affecting the EDHF pathway.