NEUROPROTECTION OF COMPLETELY LACERATED SPINAL-CORD OF ADULT-RATS BY HOMOTOPIC AND HETEROTOPIC TRANSPLANTATION

To evaluate the neuroprotective effect of transplants placed in the le sion zone after a complete spinal cord (SC) laceration, two independen t series of experiments were carried out. In the first, allogeneic or xenogeneic fetal SC was transplanted into the gaps of the damaged lowe r thoracic SC of adult rats. In the transplanted rats the incidence of life-threatening complications was reduced, and the survival rate was increased compared with the control group (lesion, without implant). Histological examination showed less damage to the neighboring SC pare nchyma in the transplanted rats. The measurement of this neuroprotecti ve effect was made in a second series of experiments. Using the same m odel of SC injury, allogeneic fetal SC, autologous peripheral nerve an d/or adipose tissue were implanted. Rats with implants of Gelfoam and damaged rats without implants were the controls. The implanted rats of all groups, including the Gelfoam group, showed a better survival rat e than the nonimplanted rats. Significantly less damage to the neighbo ring SC parenchyma was measured in implanted rats with any of the live tissues tested compared with non-implanted rats, although no signific ant differences were observed between the Gelfoam group and the nonimp lanted rats. Histological evidence of tissue implant survival was obse rved in all corresponding groups. It is concluded that the transplante d tissues tested here have a neuroprotective effect, possibly by actin g as a buffer to neurotoxic substance(s) released by the stumps, and/o r by exerting trophic effect(s) on the host.