無機ヒ素の胸腺に対するin vivo急性毒性

抄録

It has been well known that inorganic arsenicals are potent toxicans and carcinogens in humans and most animals. However, immunotoxic effects of them have not been well studied. In this study, we observed in vivo acute immunotoxicity of an inorganic arsenical. sodium arsenite. using murine models. Sodium arsenite was administered intraperitoneally into male CDF₁ mice aged 4 weeks at doses of 1.25-8.0 mg/kg (body weight) on day 0. and the effect of arsenite on thymus of these mice was assessed until day 8. As results, a half numbers of mice were died when 8 mg/ kg of arsenite were administered. The mice body weights were decreased significantly by arsenite in a dose dependent manner at doses of 1.25-4.0 mg/ kg on days 1-2, and it returned to the control level on day 4. Administered arsenite was distributed into thymus; the maximum arsenic concentrations were detected on day 1 and they dropped slowly to the control level during 8 days. The thymus weight was significantly decreased by arsenite at doses of 4 mg/kg on days 1-4. and they returned to the control levels on day 8. 4-mg/kg arsenite also decreased significantly the numbers of thymocytes of mice temporarily on day 1. Furthermore, the thymocyte blatogenesis of these mice was significantly inhibited by 4 mg/ kg arsenite on day 1. Taken together, arsenite has significant in vivo immunotoxicity both quantitatively and qualitatively on thymus, and the thymus is one of very sensitive immune organs to arsenic inhalations.