PADMAJA, K(MAJOR)ESWARA PRASAD, PPUNYA KUMARI, BSRAVANI, J2017-09-042017-09-042015-01http://krishikosh.egranth.ac.in/handle/1/5810030361THESESABSTRACT: An experiment was conducted to study the effect of Bisphenol-A (BPA) on oxidative stress during embryonic development in chicks. Fertile eggs were procured and eighty (80) eggs in two sets were assigned randomly into 4 groups of20 each. Group I served as control and received 10 μl of distilled water, groups II to IV were treated with BPA dissolved in distilled waterin three concentrations of 100μM, 250μM and 500μM respectively. A single dose of 10 μl volume injected into the aircell using microsyringe separately to 11thday old and 14th day old chick embryos. The developed embryos were sacrificed after 24 and 48 hours of BPA exposure and liver and brain tissues were collected and preserved at -20ºC for estimation of Thiobarbituric acid reacting substances (TBARS), antioxidant enzyme activities (Superoxide dismutase (SOD),Catalase (CAT),Glutathione peroxidise (GPx) and Glutathione-S-transferase (GST)), Reduced glutathione (GSH), Deoxy ribonucleic acid (DNA), Ribonucleic acid (RNA) and protein levels. The liver and brain tissues were preserved in 10% formalin for histopathological studies. The results showed a significant dose dependent increase in TBARS after 24 and 48 hours in both 11th and 14th day treated embryos in liver and brain tissues. Glutathione levels were elevated after 24 and 48 hours in both liver and brain tissues of 11th and 14th day treated embryos. Protein levels were not much altered in both liver and brain tissues, whereas a significant induction in GPx activity was observed after 24 and 48 hours in group IV followed by group III, group II compared to group I in both 11th and 14th day BPA exposed chick embryos. A significant increase in GST activity was observed after 48 hours compared to 24 hours with BPA treatment in both 11th and 14th day old chick embryos. A significant increase in SOD activity was noticed after 24 hours in all the treatment groups compared to control in liver of both 11thand 14th day BPA administered chick embryos. Whereas CAT activity was not altered much after 24 hours, but a significant increase was noticed after 48 hours in liver and brain of 11th and 14th day BPA treated chick embryos. A dose dependent decrease in DNA levels was observed in all treatment groups compared to control after 24 hours in both 11th and 14th day BPA treated chick embryos compared to control. A significant dose dependent decrease in RNA levels was observed after BPA exposure compared to control after 24 hours in both 11th and 14thday BPA treated chick embryos. In histopathological sections, degenerative, necrotic changes with mononuclear cell infiltration, congestion and proliferation of fibroblasts are prominent in liver of both 11th and 14th day BPA treated chick embryos. Neuronophagia, satellitosis, extensive demyelinating changes, proliferation of the capillaries, perineuronal vacuolation was observed in brain of BPA treated chick embryos. The study concludes that the toxic effects of BPA are dose dependent and are inversely effective with age during the embryonic development in chicks.ennullThesis