Effect of paternal exposure to gamma rays on juvenile rat forebrain.

We studied the transgenerational effect of the sublethal dose of gamma radiation on the proliferative activity of cells in the rostral migratory stream (RMS) in the brain of neonatal and young progeny of male rats exposed to the dose of 3 Gy 25 days before conception with intact control females. To label proliferating cells, the progeny received bromodeoxyuridine (BrdU) injection before sacrifice. The number of BrdU-positive cells was counted in three parts of the forebrain RMS, i.e. in the vertical arm, elbow and horizontal arm, at the 3rd, 7th, 14th, 21st and 28th postnatal days (P3-P28). In the RMS of control rats' progeny, the number of BrdU(+) cells transiently decreased at the 7th-14th postnatal days. In the progeny of irradiated rats, the dynamics of the changes was similar to that in the corresponding control groups, however, the number of BrdU-positive cells was significantly higher along the whole RMS at all intervals of investigation. These results suggest that paternal exposure to ionizing radiation induced the genome instability, which manifested itself in the progeny by alteration in proliferative activity or slackening of cell migration in the RMS.