Population Kinetics Studies in Mouse Liver Exposed Prenatally to Different Dose-Rates of Gamma Rays

Life forms are more susceptible to toxic action when they are in developmental stages, than when they have reached maturity. In view of high radio vulnerability of developing embryo, it is must to assess the effect of prenatal exposure on mammalian development. The effects of radiation are dependent not only on the total dose administered, but also on the dose-rate. In order to investigate radiation risks associated with low-doses and low-dose-rates, pregnant Swiss Albino mice were exposed to 0.20, 0.40 and 0.80 Gy of gamma rays from a Cobalt-60 source at two different dose-rates (0.0584 and 0.0091 Gy/min) on 18 day post conception, irradiated as well as control animals were allowed to reach term and deliver normally. Qualitative and quantitative estimation of liver radio lesions were made in mice progeny at Day 1 and 3 and Week 1, 2, 4, 6 and 12 of prenatal age, selecting normal hepatocytes abnormal hepatocytes and binucleated hepatocytes as parameters. Histopathological studies revealed that the pattern of radio lesions produced by different exposure doses were of the same nature but with the increase in the exposure dose radiopathological alterations became more and more pronounced. They were of greater magnitude in 0.80 and 0.40 Gy groups than in 0.20 Gy. Moreover, the radio lesions were more prominent in the high-dose-rate (HDR) subgroups then in the low-dose-rate (LDR) subgroups. This holds true for all the exposed dose-groups.