UNILATERAL GRAFTING OF FETAL NEOCORTEX INTO A CORTICAL CAVITY IMPROVES HEALING OF A SYMMETRICAL LESION IN THE CONTRALATERAL CORTEX OF ADULT-RATS

Fetal neocortical tissue (ED 14) was grafted unilaterally into a corti cal cavity made bilaterally in the sensorimotor cortex of adult rats. Transplantation was done immediately after the lesion (group TR(0), n = 8) or with 14-day delay (group TR(14), n = 8). Six rats served as le sion only controls (group LES). After long-term survival (up to 15 mon ths) the brains were photographed and surface areas of transplant and contralateral cavities were measured by means of a graphic tablet. The results show that (a) the presence of a transplant in one lesion cavi ty in the cortex decrease the size of a similar cavity in the contrala teral cortex and that (b) the better host transplant integration there is, the greater the effect on the contralateral lesion. No correlatio n between the size of the transplant and the size of the symmetric tra umatic lesion was found. The ameliorating effect of the transplant on the contralateral cortical lesion size is most likely related to the l ong-term influence of growth or trophic factors released by transplant ed cells which lead to the healing of the symmetric lesion.