Fetal nerve cell degeneration produced by thalidomide in rabbits

Abstract

The dorsal root ganglia of offspring of pregnant New Zealand White rabbits given thalidomide in varying doses were studied histologically. The treated group produced 37 normal offspring, 7 with reduction deformities, and 49 resorptions. The control group produced 22 normal and no deformed offspring. The dorsal root ganglia of the deformed fetuses showed degenerative changes particularly in the cervical and lumbar regions of the cord, exemplined by nuclear karyolysis, and edematous dissociation of the cells with wide inter‐cellular spaces. Neurons with large vesicular nuclei and prominent nucleoli, features of the sensory ganglia of the control animals, were not prominent in the cervical ganglia of the deformed fetuses. Cell counts on the sixth cervical dorsal root ganglia of a group of five severely deformed fetuses showed fewer neurons than a group of control fetuses or a group of apparently normal experimental fetuses. However it was not possible to show from this experiment whether the reduction in the number of sensory neurons was causative of, or consequent to, the reduction deformities of the forelimbs.