Abstract

Mercury is a toxic metal used in industries and in the process of gold extraction. The inorganic form of mercury, Hg²⁺, is known to cause alterations in the renal system. In this context, this work evaluated the effects of oral HgCl₂ exposure in markers of nephrotoxicity and hepatotoxicity and gastrointestinal Hg levels. Moreover, it evaluated the preventive effects of ZnCl₂. Male Wistar rats were exposed orally for five days to ZnCl₂ (27 mg/kg/day) and subsequently for five days to HgCl₂ (5 mg/kg/day). Rats were sacrificed 24 h after last HgCl₂ administration. HgCl₂ exposure caused a significant increase in serum urea levels and a decrease in serum lactate dehydrogenase activity without altering gastrointestinal δ-aminolevulinic acid dehydratase activity. Zn pre-exposure avoided the increase in urea levels. Still, Zn supplementation increased stomach Hg accumulation and decreased Hg intestinal burden. These results suggested that the oral exposure to five doses of HgCl₂ is nephrotoxic, and the preventive effect of zinc can be related to the lower intestinal Hg absorption due to stomach Hg retention.

Keywords: Nephrotoxicity; Inorganic mercury; δ-ALA-D; Lactate dehydrogenase