Transplantation of embryonic brain tissue into the brain of adult rats after hypoxic hypoxia.

Brain cortex tissue of 20-day-old rat embryos ( E20 ) was transplanted into the brain parietal region of adult Wistar rats 22 days following their exposure to acute hypoxic hypoxia. 91 days after hypoxia and 69 days after transplantation the rats were killed and their brain was studied histologically. Hypoxia has been found to cause strong dystrophy, irreversible degeneration (shrunken and lysis) and the death of numerous cortex neurons. Nevertheless the transplanted E20 rat brain tissue develops in 100% of cases in the brain of recipients. Transplants have a considerably large volume (7 mm3) and establish a close morphological connection with the neughbouring nervous tissue of the host's brain. Transplants contain viable nerve and glial cells. E20 rat brain transplants improve to a certain extent the state of hypoxia-exposed dystrophic neurons of the recipient's brain. The decay products released from the transplanted E20 rat brain tissue influence the recipient's brain tissue, and neurons of the transplants establish a close morphological, probably synaptic, connection with neurons of the host's brain tissue.