Newly formed host cells in a grafted juvenile neocortex express neurone-specific marker proteins

Recently we reported that a mouse foetal neural graft, when transferred into a lesioned juvenile neocortex, may induce cortical repair and stimulate proliferation of the host cells. The present study was focused on an immunohistochemical identification of neurones among these newly generated cells. Adjacent sections from the brains already used in our previous study were stained either with an antibody against the host-specific Thy-1 antigen, or with neurone-specific antibodies recognizing the microtubule-associated protein MAP2, the heavy subunit of neurofilaments and parvalbumin. Dividing cells, labelled repeatedly during the first three post-operative days with 3H-thymidine, were detected after 2 months by autoradiography. We found that in the repaired neocortical region newly formed host cells, whose distribution resembled the one found in an intact neocortex, also contained neurones. These new data corroborate our previous suggestion that a juvenile mammalian neocortex participates, after lesioning and under the presence of a foetal neural graft, in its own repair by the formation of new cells, including neurones.