Postnatal survival and growth of mouse irradiated in utero with low dose.

In order to investigate radiation risks associated with low dose and low dose-rates, pregnant Swiss albino mice were exposed to gamma rays, 0.80 Gy from a cobalt-60 source at two different dose-rates (0.0795 and 0.0012 Gy/min) on 18 day post conception. In females exposed to lower dose-rate (0.0012 Gy/min), litter size was found to be decreased, while those exposed to higher dose-rate (0.0795 Gy/min), it remained unaltered. In both groups, appearance of fur and development of complete fur were delayed, whereas gait was delayed only in higher dose-rate group. Male offspring exhibited a biphasic mode of weight loss, while female offspring after an initial weight loss at 1 week, displayed a continuous recovery, but could not attain the normal weight till 12 weeks of age. It appears that higher dose-rate is more effective in delaying the appearance of physiological markers and weight loss, while in terms of litter size lower dose-rate (0.0012 Gy/min) is more effective.

Depletion of ovarian oocytes in sublethally exposed mice to gamma radiation and its modification by 2-mercaptopropionylglycine (MPG).

Adult female Swiss albino mice were exposed to 0.6, 1.2 and 2.4 Gy of 60Co gamma radiations in presence and absence of MPG. Quantitative studies were done in serial sections of ovary at 1, 3, 5, 7, 14 and 35 days after exposure. Primary follicles were found to be most radiosensitive. The depletion in the various types of follicles was checked to some extent by prior administration of MPG, but MPG could not prevent the complete elimination of all types of follicles by the last autopsy interval studied.