Fetal grafts alter chronic behavioral outcome after contusion damage to the adult rat spinal cord.

In the present experiments, we have examined the capacity of intraspinal transplants to effect alterations in certain locomotor behaviors after spinal contusion injuries. An electromechanical impactor that was sensitive to tissue biomechanical characteristics was used to produce rapid (20 ms) compression injuries to the thoracic spinal cord (T8). Suspensions of fetal spinal tissue (14-day) were placed at 10 days postinjury into the intraspinal cavity created by these reproducible spinal injuries. In the pre- and postinjury period, a number of general and sensitive motor behaviors were used to characterize the immediate and long-term progress of hindlimb behavioral recovery over an extended period of time (73 days). Our data reveal that a lasting alteration in some motor behaviors can be achieved by suspension grafts. While little improvement in some generalized motor tasks (inclined plane analysis, grid walking) takes place, fetal transplants precipitate a rapid and enduring change in certain motivated fine motor behaviors (gait analysis). The base of support and stride length of the hindlimbs were improved by 7 days post-transplantation and the effect was stable over time. The angle of rotation was, however, not altered. The lasting effect in two gait parameters noted was accompanied by the presence of well-developed spinal grafts that often fused with the host spinal parenchyma. These results provide the first documentation of an influence of fetal transplants on motivated locomotor capacity in a well-characterized spinal injury model that mimics lesions seen in the contused adult human spinal cord.