Structural and functional repair of the corticospinal tract in the adult rat by transplantation of olfactory ensheathing cells

We made unilateral lesions destroying the upper cervical corticospinal tract in adult rats. We prepared a suspension of ensheathing cells cultured from adult rat olfactory bulb and injected it into the lesion site. We observed that this induced unbranched, elongative growth of the cut corticospinal axons, which grew through the transplant and continued uninterruptedly into the denervated caudal host tract. In a series of functional studies we established that rats with complete corticospital tract transections and no transplanted cells were unable to acquire the ability to use the forepaw on the lesioned side for directed reaching. However, rats in which we had transplanted cells that had formed a continuous bridge across the lesion were able to acquire directed forepaw reaching on the operated side.