Pantnagar Journal of Research

Abstract

The present study was conducted to know the effects of nanosilver administration at NOAEL dose on immune responses in Wistar rats for a period of 90 days. Thirty-five, 6-week-old, Wistar rats of both the sexes were divided randomly in two groups. Group 1 with 20 rats served as control. Group II comprising of 15 rats were administered silver nanoparticle through distilled water per os at NOAEL dose rate of 30 mg/kg body weight/day from 0 day of experiment till 90th days post treatment (DPT). Five rats from each group (I and II) were slaughtered at 0th (5 rats from group I only, was slaughtered), 30th, 60th and 90th DPT and blood and spleen were collected at these intervals to study the effect of nano-silver on both HIR and CMI. In group II, reduced titre of HI and ELISA test values, significant decrease in serum gamma globulin values at 90^th DPT showed the deleterious effect of nanosilver on the humoral immune response. Decreased thickness of the DNFB applied skin in delayed type hypersensitivity reaction and NBT positive cells in macrophage function test in the test rats showed harmful effect of the nano-silver on the cell mediated immunity. Significant decrease in Δ OD during the lymphocyte stimulation test performed on splenocytes of the test rats using Con-A, PHA-M and LPS mitogens also showed lymphocytotoxic effect against both mature and immature T lymphocytes and B lymphocytes. It was concluded from the present studies that nanosilver exerted adverse effects on immune responses in Wistar rats at NOAEL dose for a period of 90 days.