[Postnatal cellular reactivity of the optic nerve after enucleation in the rat. Quantitative aspects in relation to myelinization].

The use of an experimental procedure based upon progressive postoperative delays allowed the quantification of the effects of enucleation performed at the ages of 2, 8 and 20 days, corresponding to key stages of the postnatal maturation of the optic nerve, namely premyelination, myelination and postmyelination. Two main events were noteworthy regarding cell reactivity. The higher the age of the animals at operation, the lower was the proliferation, and the larger was the time lapse between operation and the peak of proliferation. The interferences between reaction gliosis and myelination gliosis depended upon the developmental stage of the optic nerve. This reflects a progressive loss of plasticity.