Early Postnatal Development and Long Term Prognosis of Experimentally-Induced Microcephalic mice

Abstract

This study was undertaken in an effort to elucidate the postnatal development and prognosis of experimentally-induced microcephalic mice. Microcephalic mice were produced by injecting cytosine arabinoside to the pregnant mice as described previously. In the treated mice, the postnatal development such as the bodyweight gain, weaning and reflex development and behavioral organization, and the prognosis such as deformities of the vertebral column and natural death were examined. Body-weight of the treated mice was significantly lower than that of the control through the entire period tested. The microcephalic youngsters weaned several days later than the control. The primitive reflexes such as cross extensor reflex, pivoting and rooting reflex were either accelerated, lasted longer or rather weak in the treated mice. Righting reflex, hindlimb grasp reflex and bar holding ability were poor and completions of these reflexes were delayed. The deformities of the vertebral column were examined rentogenographically as they matured. Kyphosis appeared by 30 to 60 days of life and gradually progressed. During 250 days of observation, about one half of treated mice were dead, whereas only I was dead in the control, thus indicating shorter survival in the microcephalic mice.