CHARACTERISTICS OF HUMAN FETAL SPINAL-CORD GRAFTS IN THE ADULT-RAT SPINAL-CORD - INFLUENCES OF LESION AND GRAFTING CONDITIONS

The present study evaluated the growth potential and differentiation o f human fetal spinal cord (FSC) tissue in the injured adult rat spinal cord under different lesion and grafting conditions. Donor tissue at 6-9 weeks of gestational age was obtained through elective abortions a nd transplanted either immediately into acute resection (solid grafts) or into chronic contusion (suspension and solid grafts) lesions (i.e. , 14-40 days after injury) in the thoracic spinal cord. The xenografts were then examined either histologically in plastic sections or immun ocytochemically 1-3 months postgrafting. Intraspinal grafts in acute l esions demonstrated an 83% survival rate and developed as well-circums cribed nodules that were predominantly composed of immature astrocytes . Solid-piece grafts in chronic contusion lesions exhibited a 92% surv ival rate and also developed as nodular masses. These grafts, however, contained many immature neurons 2 months postgrafting. Suspension gra fts in chronic contusion lesions had an 85% survival rate and expanded in a nonrestrictive, diffuse pattern. These transplants demonstrated large neuronally rich areas of neural parenchyma. Extensive neuritic o utgrowth could also be seen extending from these grafts into the surro unding host spinal cord. These findings show that human FSC tissue rel iably survives and differentiates in both acute and chronic lesions. H owever, both the lesion environment and the grafting techniques can gr eatly influence the pattern of differentiation and degree of host-graf t integration achieved. (C) 1997 Academic Press.