The morphological changes of the spinal motoneurons after peripheral nerve transection in the chicken

The cellular response of motoneurons and glial cells of the chicken spinal cord was observed following brachial plexectomy. The axotomized motoneurons initially showed an irregular nuclear membrane. Subsequently, they showed the appearance of a perineuronal space and the increase in number of glycogen granules. At 10 and 20 d post-operatively, the axon reaction reached a peak and the axotomized motoneurons contained abundant glycogen granules, and tended to an increase electron density in electron microscopy or an increased basophilia in light microscopy compared to those of the control. Elongated microglial cells appeared as satellites to the axotomized cells. The perineuronal space extended with the post-operative days. From 30 post-operative days forward, the axotomized motoneurons recovered with the post-operative days. The axotomized motoneurons did not show chromatolysis during axon reaction.