Decreased membrane fragility of mouse erythrocytes by small dose of methylmercury and its restoration by coadministered selenite.

Abstract

Med., 1982, 137 (3), [297][298][299][300][301][302][303] Female IVCS mice were fed methylmercury at a low dose level (10 nmoles/g feed) with coadministration of selenite (0, 8,20 or 50 nmoles/ml of drinking water) for one week or two weeks. Mice fed methylmercury alone showed the decreased fragility of erythrocytes membrane when compared with the non-treated control. Coadministration of selenite produced such a change to smaller extents than methylmercury treatment alone. Mercury levels in the blood varied according to the dose level of selenite (the highest level was found in methylmercury alone group). -membrane fragility; blood; mouse; methylmercury; selenite In the in vitro experiments, hemolysis was observed at concentrations of methylmercury over 10-4 M in rat erythrocytes (Ohmiya 1977;Tanaka and Nakai 1977). Elevated fragility of erythrocytes was observed in rats injected subcutaneously for 12 days with daily dose of 10 mg methylmercury chloride/kg (Okuda and Tsuzuki 1977). Coadministration of selenite with methylmercury produced changes in mercury retention in the blood of mice and rats (Iwata et al. 1973;Stillings et al. 1974; Ohi et al. 1975;Yamane et al. 1977;Sumino et al. 1977; Magos and Webb 1977;Satoh and Suzuki 1979;Naganuma and Imura 1980), but has not been studied for hemolytic effects. The change of mercury retention in the blood by coadministered selenium was not always unidirectional by dose levels and dose combination of both chemicals, duration of dosing and animal species.In this study, to elucidate subtle effects of methylmercury on erythrocytes, a low dose level was selected with varying coadministered dose of selenite. MATERIALS AND METHODSForty-four female IVCS mice, 17 weeks-old weighing 27 to 30 g, were divided into nine groups and fed methylmercury (10 nmoles/g feed) and selenite (0, 8,20 or 50 nmoles/ml of drinking water) for one week or two weeks. The control (commercial chow and tap water only) was bred only for one week.

A review of the factors that influence erythrocyte osmotic fragility

“…Okuda & Tsuzuki (1977) reported decreased erythrocyte osmotic fragility in low doses of methylmercury and no change in osmotic fragility in higher doses in male Wistar rats. Erythrocyte osmotic fragility decreased in female mice fed methyl mercury (10nmoles/g feed) (Yamamoto & Suzuki, 1982). Erythrocytes treated with mercuric ions showed resistance to osmotic shock after 5 minutes of incubation but they began to haemolyse when the incubation time was increased (Zolla et al, 1994).…”

Inhibition of osmotic permeabilty of caprine erythrocytes by mercuric chloride in osmotic fragility models

“…Okuda & Tsuzuki (1977) reported decreased erythrocyte osmotic fragility in low doses of methylmercury in male Wistar rats but no change was recorded in erythrocyte osmotic fragility in higher doses. The erythrocytes from female mice fed methylmercury (10nmoles/g feed) had decreased osmotic fragility (Yamamoto & Suzuki, 1982). Erythrocytes treated with mercuric ions showed resistance to osmotic shock after 5 minutes of incubation but they began to haemolyse when the incubation time was increased (Zolla et al, 1994).…”

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Mice were fed methylmercury (10nmol/g feed) and selenite (0,8,20 or 50nmol/ml drinking water) for one or two weeks. Doses of selenite and duration of feeding were determining factors of total mercury and inorganic mercury concentrations in organs.

Increasing the dose of selenite produced the following results: concentration of total mercury in creased in the brain and liver and decreased in the blood, kidneys and spleen; concentration of inorganic mercury increased in the liver and spleen, decreased in the kidneys, and remained unchanged in the brain; the rate of inorganic mercury to total mercury increased in the liver and spleen, decreased in the brain, and remained unchanged in the kidneys.

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“…Mice were fed methylmercury (10nmol/g feed) and selenite (0,8,20 or 50nmol/ml drinking water) for one or two weeks. Doses of selenite and duration of feeding were determining factors of total mercury and inorganic mercury concentrations in organs.…”