THE ELECTROLYTIC LESION AS A MODEL OF SPINAL-CORD DAMAGE AND REPAIR IN THE ADULT-RAT

The utility of the electrolytic lesion as a model of spinal cord injury and repair has been studied in adult Wistar rats. Lesions were created using an 0.1 mA current applied for 30 s in the right hand intermediate zone of the cord, at the level of the 10th thoracic vertebra. After three months, secondary pathological changes at these sites resulted in a variable degree of grey matter atrophy, cavitation, macrophage infiltration and loss of white matter in the dorsolateral funiculus. Functionally, lesioned animals exhibited an incomplete spastic paraparesis of the right hind limb, had normal scores on the inclined plane test, but showed subnormal performance of the right hind limb on the Tarlov scale. Spinal cord neurones dissociated from E14 rat embryos survived for at least 3 months if transplanted into a freshly made electrolytic lesion. However, these implants had no ameliorating effect on the motor deficit induced by electrolytic lesions. It was concluded that the electrolytic lesion represents a useful model for qualitative studies on secondary histopathological changes in the injured cord. Electrolytic lesions also support long-term survival of implanted spinal neurones. However, the possible trophic influence of these implants on motor and sensory tracts could probably be better studied using neonatal, rather than adult rats.