Chronic intoxication by methylmercury leads to oxidative damage and cell death in salivary glands of rats

Abstract

Methylmercury (MeHg) is one of the most toxic species of mercury, causing several systemic damages; however, its effect on the salivary glands has rarely been explored to date. This study was aimed at analyzing the mercury deposit, oxidative stress markers, and cell viability in parotid and submandibular rat salivary glands after chronic methylmercury intoxication. Herein, forty male Wistar rats (40 days old) were used in the experiment. The animals of the experimental group were intoxicated by intragastric gavage with MeHg at a dose of 0.04 mg per kg body weight per day for 35 days, whereas the control group received only corn oil, a diluent. After the period of intoxication, the glands were obtained for evaluation of total mercury deposit, cell viability, and the malondialdehyde (MDA) and the nitrite levels. Our results indicated mercury deposits in salivary glands, with a decrease in cell viability, higher levels of MDA in both glands of intoxicated animals, and a higher concentration of nitrite only in the submandibular gland of the mercury group. Thus, the intoxication by MeHg was able to generate deposits and oxidative stress in salivary glands that resulted in a decrease in cell viability in both types of glands.

Maternal methylmercury exposure changes the proteomic profile of the offspring’s salivary glands: Prospects on translational toxicology

“…Recent biomonitoring has revealed hair Hg levels as high as 75 ppm [ 41 – 43 ], which may represent a MeHg weekly intake of 52.5 μg/kg as suggested by Crespo-Lopez [ 1 ]. Thus, the MeHg dose used in this study (40 μg/kg/BW) resembles the exposure detected in chronically exposed humans and is widely used in validated research with rats [ 11 , 23 , 44 – 46 ]…”

Effects of Mercury, Lead, Arsenic and Zinc to Human Renal Oxidative Stress and Functions: A Review

“…However, normal renal function was recovered after thirteen episodes of hemodialysis [24]. However, studies with Wistar rats have shown that administration of of CH 3 Hg + at a dose of 0.04 mg/kg body weight for 35 days was able to produce deposits of this metal and induction of oxidative stress at the salivary gland level [51]. Similarly, in rats chronically exposed to of CH 3 Hg + , fibrotic changes were observed in the glomeruli, and deposition of immunoglobulin G (IgG), immunoglobulin M (IgM) and complement component C3 were detected along the glomerular basement membrane [52].…”

Methylmercury-induced cytotoxicity and oxidative biochemistry impairment in dental pulp stem cells: the first toxicological findings

“…However, only few studies have investigated the effects of MeHg on oral structures. Some of these focused on the amount of organic and inorganic mercury in human saliva (Leistevuo et al, 2001) and recently our group have shown the impact of mercury accumulation and toxicity on rat salivary glands (Lima et al, 2018;Farias-Junior et al, 2017; and human periodontal ligament fibroblast (Nogueira et al, 2019). Nevertheless, no studies have been specifically evaluated the effect of MeHg on human dental pulp cells.…”