Efeito in vitro de Paullinia cupana no metabolismo oxidativo de espermatozóides humanos expostos ao cloreto de metilmercúrio

Abstract

Investigations suggests that methylmercury (MeHg) toxicitiy is related to oxidative stress promotion caused by lipid peroxidation of cell membranes as well as genotoxicity. The methylmercury (MeHg) exposition causes production of adverse effects as deterioration of semen quality, testicular degeneration, and male reproductive failure. Since human sperm is a vulnerable cell investigations analyzing the antioxidant protection of plant extracts on MeHg exposition is relevant. Among Brazilian food supplements we found guaraná (Paullinia cupana, Mart.) which is rich in caffeine, other metaxanthynes and catechins. Previous studies showed that guaraná present antioxidant, antimutagenic, anticarcinogenic properties that could exert protective effect of sperm cells exposed to MeHg. Therefore, an in vitro protective role of guaraná (Paullinia cupana, Mart.) viability and oxidative stress modulation of human sperm cells exposed to methylmercury intoxication was here in investigated. The human sperm cell collected from donators were counted, aliquoted and submitted to four treatments negative control (C), MeHg exposition (MeHg, 60 μM); (3) Guaraná supplementation (Gua, 10 mg/mL) and MeHg exposition plus guaraná suplementation (MeHg-Gua). During the treatment exposition the samples were maintained at 37oC at 95% CO2 incubation. The viability of spermatozoa was analyzed by MTT reduction assay. Lipoperoxidation was estimated by determination of the thiobarbituric acid derivative of MDA (TBA-MDA) using a sensitive highperformance liquid chromatographic (HPLC), reactive oxygen species (ROS) was verified by testing with fluorimetric 2′ 7′-dichlorofluorescein diacetate (DCFH-DA) assay. Protein carbonylation and thiol were evaluated spectrophotometrically. The guaraná treatment increase the sperm viability exposed to MeHg as well as decreased the lipoperoxidation, ROS and protein carbonylation levels. Thus, we conclude that the guaraná showed in vitro protective effect of human sperm against MeHg exposition.