Effect of subchronic fluoride exposure on immune status and histopathology in rats and its ameliorative measures

Abstract

The aim of the present investigation was to study the effects of fluorideinduced toxicity in rats on immunity and histopathology and its possible amelioration with boron, calcium chloride, and aluminium silicate. Sixty-four male Wistar albino rats, aged 8 to 12 weeks, were divided into eight groups of eight rats each. The control group, A, was given normal water while the treatment groups, B, C, D, E, F, G, and H, were given 30 ppm fluoride ion (F), 30 ppm F with 50 ppm boron, 50 ppm boron, 30 ppm F with 50 ppm calcium chloride, 50 ppm calcium chloride, 30 ppm F with 50 ppm aluminium silicate, and 50 ppm aluminium silicate, respectively. After four months, the rats were sacrificed, and blood and tissues collected for immune and histopathological studies, respectively. The effect on humoral and cell-mediated immunity was assessed by the antibody titre against sheep red blood cells and the lymphocyte proliferation assay, respectively. There was a significant decrease in cellmediated immunity in rats given F alone and F in combination with aluminium silicate. Histopathological changes due to F toxicity were observed in the liver with vacuolar degeneration and hepatocellular necrosis, in the kidney with tubular casts, in the thyroid with loss of colloid with degeneration of epithelial cells, in the thymus with loss of lymphocytes and plasma cells, and in the spleen with loss of lymphocytes. These histopathological changes were ameliorated by supplementation with boron and calcium chloride, but not with aluminium silicate. Thus, both boron and calcium chloride, at 50 ppm, may effectively ameliorate F toxicity in the rat.