Improved Survival Rate and Reduced Spinal Cord Parenchymal Destruction of Rats Subjected to Complete Spinal Cord Transection and Heterotopic Tissue Transplantation

Complete experimental spinal cord (SC) laceration, besides paraplegia, involves various somatic and autonomic dysfunctions which can cause death within days or a few weeks after lesioning (Das, 1989). After SC injury, the neural damage occurs beyond the lesioned site, involving the neighboring tissue through multiple secondary metabolic (Kao, 1977; Balentine, 1988), excitotoxie (Faden, 1988), and vascular (Goodman, 1979) alterations, which ultimately lead to destruction or atrophy of neurons far from the injured zone (Feringa, 1988). Recently we reported (submitted for publication) on the neuroprotective effect of fetal SC grafts transplanted to the SC of adult rats after complete laceration. We evaluated the effects of heterotopic grafts using the same model of SC injury to the lower thoracic region (T7-T8 level). Five groups of 6 rats each were formed: group 1, not transplanted (control group); group 2, homotopically transplanted with allogeneic fetal SC E-15; groups 3, 4, and 5, autotransplanted with adipose tissue, peripheral nerve, and salivary gland, respectively. The space between the 2 SC stumps was filled immediately with the corresponding tissue implant. Clinically, rats were evaluated for rate of survival, time of reflex return, and percentage body weight loss. To evaluate implant survival and parenehymal destruction, rats were sacrificed 12 days after surgery. Three representative SC slides of each rat were photographed to carry out the morphometric analysis by a stereological method: the simple square lattice test system (the destroyed parenchymal area was drawn on millimetric paper; the number of 5 mm crosses in this area was measured). TABLE