Neural transplants: volumetric analysis of their growth and histopathological changes.

Neocortical transplants from 15-, 18- and 22-day rat embryos were transplanted into the cerebellum of the host animals. The necrotic changes and growth in the transplants, the blood in relation to them, and the space containing CSF were analyzed quantitatively in a developmental sequence. The histopathological changes were seen to last for 6-8 days. The neural tissues after initial regression showed recovery, and started to grow in size after 3-4 days. The transplants from 15-day donors showed the highest growth, and this was followed in sequence by those from 18- and 22-day embryos. Techniques involved in manipulation and dissection of the donor embryos, and in transplantation of the tissue, were found to play an important role in the necrotic and other changes in the transplants.