Effect of dietary co-administration of sodium selenite on sodium arsenite-induced ovarian and uterine disorders in mature albino rats.

The subchronic treatment of mature female Wistar-strain albino rats in diestrous phase with sodium arsenite at a dose of 0.4 ppm/100 g body weight/rat/day via drinking water for period of 28 days (seven estrous cycles) caused a significant reduction in the plasma levels of leutinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol along with a significant decrease in ovarian activities of delta five, 3 beta-hydroxysteroid dehydrogenase (Delta5,3beta-HSD), and 17 beta-hydroxysteroid dehydrogenase (17beta-HSD) followed by a reduction in ovarian and uterine peroxidase activities. A significant weight loss of the ovary and uterus was also observed after this treatment, along with a prolonged diestrous phase and a high accumulation of arsenic in the plasma and these organs. Moreover, sodium arsenite was also responsible for ovarian follicular and uterine cell degeneration characterized by a high number of regressing follicles and a reduction in the uterine luminal diameter, respectively, in comparison with the controls. A dietary supplementation of sodium selenite at the dose of 0.6 mg/100 g body weight/rat/day for a period of 28 days along with arsenic treatment minimized the gonadal weight loss significantly and increased the activities of the ovarian steroidogenic enzymes as well as the ovarian and uterine peroxidase at the control level. Selenium was also able to increase the plasma levels of LH, FSH, and estradiol toward the control level. Vaginal smears showed normal estrous cyclicity in sodium selenite-supplemented arsenic-treated rats along with lower arsenic levels in the plasma and gonadal tissue in comparison with arsenic-only-treated rats. Histological sections of ovary and uterine tissues in the control and experimental groups confirmed that sodium selenite supplementation was able to prevent arsenic-induced histopathological changes in the ovary and uterus. Plasma levels of norepinephrine and dopamine in the midbrain and diencephalon decreased significantly, whereas the serotonin level was increased significantly after 28 days of sodium arsenite treatment. All of these parameters were, in most cases, unchanged from the control level when sodium selenite was co-administered with sodium arsenite. Arsenic intoxication was also associated with increased liver weight and elevation in the activities of hepatic and renal acid phosphatase, alkaline phosphatase, and transaminases, but selenium co-administration was not able to change these toxic effects of arsenic. The results of our experiments indicate the significant protective action of sodium selenite on arsenic-induced toxicity in the female reproductive system, while there was no significant protective effect of selenium on arsenic-induced toxicity in other organs.