The present study was designed to investigate the oxidative stress, which is due to the effect of low doses of gamma irradiation. Animals were divided into 6 groups, where the first group kept as control group, while 2 nd , 3 rd , 4 th , 5 th and 6 th groups were exposed to gamma ray at 1.5 Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy once weekly for one month respectively. Rats were subjected to gamma radiation and nitric oxides (NO), superoxide dismutase (SOD), malondialdehyde, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and white blood cells (WBCs) were measured. SOD recorded highly significant decrease with percent change -22.7%, -25.01%, -55.01% -55.4% and -56.38% respectively in groups which were exposed to 1.5, 2, 2.5, 3 and 3.5 Gy. MDA serum level have a significant increase in groups which were exposed to successive doses of 1.5 Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively with percent change 25.7% , 41.8% 59.1% 65.6% 75.8% consequently as compared to control group. Nitric oxide serum level is markedly showed highly significant increase in rats exposed to successive dose of 1.5, Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively with percent change 59.69%, 74.17%, 87.1%, 120.1% and 130.6% consequently as compared to control group. ALT and AST recorded highly significant increase in rats exposure to successive doses of 1.5, Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively. On the other hand WBCs recorded highly significant decreased in rats exposed to successive dose of 1.5, Gy, 2 Gy, 2.5 Gy, 3 Gy and 3.5 Gy respectively. WBCs recorded percent change -26.11%, -32.3%, -47.8%, -50.1% and -53.6% respectively as compared to control group.
