[Regeneration of the optic nerve of Xenopus laevis after argon laser injury].

Following mechanical lesion of the optic nerve (ON), lower vertebrates are capable of regeneration of the ON and regain visual function. We have studied, by light and electron microscopy, regeneration of the larval ON of Xenopus laevis after treatment with the argon laser. The laser energy is absorbed by the neurothelial pigment and provokes a burned crater and vesiculation in the interior of the ON. In contrast to the mechanically induced process, axons regenerate, after laser treatment, within the nerve and do not sprout into the neighboring tissue. The regenerating ON is not vascularized. Immediately after laser treatment, a loss of myelin, hypertrophy, phagocytic activity, and local rearrangement of glial cells are observed. After four weeks, myelination is still irregular. Glial cells have regained their normal aspect.