Metallothionein, essential elements and lipid peroxidation in mercury-exposed suckling rats pretreated with selenium

Abstract

Detoxification of mercury (Hg) with selenium (Se) in the early postnatal period with regard to the expression of metallothionein protein (MT), essential element status, and lipid peroxidation level in tissues has not been studied. Seven-day-old Wistar pups were orally pretreated with Se [6 μmol Na2SeO3/kg body weight (b.w.)] for 3 days and then cotreated with Hg (6 μmol HgCl2/kg b.w.) for the following 4 days. This group (Se + Hg) was compared to the groups treated with Hg, Se, or vehicle (control). Compared to the Hg-group, Se + Hg-group exhibited lower renal MT expression, reduced accumulation of Hg, Cu and Zn, and reduced excretion of Se, Hg and Zn in urine. In the liver, MT was stimulated by Se treatment in both, Se and Se + Hg-group. Hepatic and brain levels of the endogenous essential elements Cu, Fe, Mg, and Zn remained unchanged in all of the studied groups. Brain Hg levels and oxidation of lipids measured as thiobarbituric acid reactive substances were diminished in Se + Hg-group of pups compared to the Hg-group. This study suggests that Se pretreatment can help reduce Hg in the tissues of suckling rats, simultaneously preventing impairment of essential element levels in the kidneys and their excessive excretion via urine. Also, Se was shown to prevent oxidative damage of lipids in the brain, which is particularly susceptible to Hg during the early postnatal period.

A Summary of New Findings on the Biological Effects of Selenium in Selected Animal Species—A Critical Review

“…Selenium is considered to be an antidote in the treatment of mercury intoxication [ 158 ], it may modulate Hg toxicity through the influence on Hg deposition in tissues, as well as Hg-induced oxidative stress, inflammation, excitotoxicity, and other pathways [ 127 ]. Studies by Orct et al [ 135 ] demonstrated the protective effect of selenium on oxidative lipid damage in the brain, which is extremely sensitive to mercury during the early postnatal period. Severe selenium deficiency causes irreversible brain injury [ 159 ].…”

“… Physiological effects of selenium. Selenium is known for its antioxidant, antimutagenic and anticarcinogenic properties, it also acts against microbes as well as parasites and has antiinflammatory effects, engages in metabolism, growth and development, protects organs from oxidative stress, affects immune function and improves fertility [ 2 , 47 , 48 , 49 , 50 , 53 , 54 , 60 , 82 , 87 , 104 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 ]. …”

Oxidative stress and cytotoxic effects of silver ion in mouse lung macrophages J774.1 cells

“…It is well known that MT chelates various metals (e.g., cadmium, copper, zinc, mercury and silver) (Carpenè et al ., ; Figueira et al ., ; Mulley et al ., ; Orct et al ., ). In the present study, the mRNA levels of MT1 and MT2 were significantly increased by Ag + 4 h after exposure, then decreased as the exposure time increased (Fig.…”

The role of metallothioneins, selenium and transfer to offspring in mercury detoxification in Franciscana dolphins ( Pontoporia blainvillei )

“…In terrestrial mammals, such as rats and mice, binding of Hg to MT has been demonstrated and induction of these proteins after Hg exposure (Morcillo and Santamaria, 1993;García-Sevillano et al, 2015;Orct et al, 2015). However, the role of MT in the detoxification of Hg is controversial; studies in marine mammals have indicated that a small percentage of Hg is bound to MT in liver and kidney (Decataldo et al, 2004;Ikemoto et al, 2004aIkemoto et al, , 2004b.…”