INFLUENCE OF PRENATAL IRRADIATION ON 2ND-GENERATION MICE

Pregnant mice were irradiated with 0.5 and 2 Gy on the 13th gestationa l day. Offspring were raised until sexual maturity at 2 months of age. Mice from prenatally irradiated mothers and unexposed fathers, or fro m prenatally irradiated fathers and unexposed mothers, or from parents who had both been prenatally irradiated were mated, resulting in the birth of several mice. These second generation mice were tested as adu lts for hearing thresholds, with the ABR technique, subjectively to ba lance tests, and investigated morphologically. Hearing levels were fou nd to be normal and the organ of Corti showed only minor changes of it s inner and outer hair cells as shown by transmission and scanning ele ctron microscopy. It is concluded that prenatal irradiation does not s eem to cause mutations leading to impaired hearing and balance in seco nd generation mice.