Efetividade do (PhSe)2 em proteger contra a toxicidade do HgCl2

Abstract

Mercury (Hg) is a non-essential metal without biological function and also an environmental pollutant originating from various sources, especially from areas of mineral exploration and intense industrial activity. It is well known that Hg has a high affinity for thiol groups (SH) causing several biochemical changes that induce oxidative stress. On the other hand, selenium (Se) is an essential trace element involved in many processes in metabolism, especially which are related to antioxidant defense system. The diphenyl diselenide (PhSe)2 is an organic selenium compound with pharmacological properties, such as antioxidant and anti-inflammatory. The objective of this study was to evaluate the protective effect of (PhSe)2 against intoxication induced by mercuric chloride (HgCl2) poisoning. For this Swiss albino mice (17-25g) were treated for five consecutive days with (PhSe)2 5.0 mg/kg or canola oil by oral gavage and with HgCl2 5.0 mg/kg or saline by subcutaneous injection for more five days. The animals were sacrificed 24 hours after the last administration of HgCl2 and samples of blood, kidney and liver tissue were collected for δ-aminolevulinate dehydratase (δ-ALA-D) activity assays. The activity of serum AST and ALT and serum urea and creatinine levels were assessed as parameters of hepatic and renal toxicity, respectively. Oxidative parameters, total thiols, non-protein thiols and the levels of thiobarbituric acid species were also evaluated. Levels of Hg and Se were determined in tissues. The animals exposed to mercury showed an inhibition of blood δ-ALA D activity, which was partially prevented by (PhSe)2. Regarding the parameters of liver and kidney toxicity, animals exposed to Hg showed an inhibition of ALT activity and an increase in creatinine levels, been this last completely prevented by (PhSe)2. On oxidative parameters evaluated, a decrease in thiobarbituric acid reactive specimens (TBARS) levels and an increase in non-protein thiols in the renal tissue were observed. This increase was partially prevented by (PhSe)2. Animals exposed to Hg showed high levels of this metal in the kidney, liver and blood. Animals exposed to Hg and pre-treated with (PhSe)2 showed a decrease of Hg levels in the blood and an increased in the liver when compared to those only treated with Hg. Therefore, considering the results presented and the antioxidant properties of (PhSe)2 and the mechanisms underlying the toxicity of mercury, it is believed that (PhSe)2 may be a potential agent against mercury poisoning.