Survival and migration of human and rat olfactory ensheathing cells in intact and injured spinal cord

Abstract

Increasing evidence indicates the potential of olfactory ensheathing cells (OECs) for treating spinal cord injuries. The present study compared proliferation and migration of adult rat and human OECs transplanted into the spinal cord of athymic (immunodeficient) rats. OECs were purified from the nasal lamina propria and prelabeled with a cytoplasmic dye. After OEC injection into the thoracic spinal cord, animals were perfused 4 hr, 24 hr, and 7 days later. Both rat and human OECs showed similar migration. Cells were seen leaving the injection site after 4 hr, and by 7 days both rat and human OECs had migrated approximately 1 mm rostrally and caudally within the cord (rat: 1,400 +/- 241 microm rostral, 1,134 +/- 262 microm caudal, n = 5; human: 1,337 +/- 192 microm rostral, 1,205 +/- 148 microm caudal, n = 6). Proliferation of transplanted OECs was evident at 4 hr, but most had ceased dividing by 24 hr. In 10 animals, the spinal cord was injured by a contralateral hemisection made 5 mm rostral to the transplantation site at the time of OEC transplantation. After 7 days, macrophages were numerous both around the injury and at the transplantation site. In the injured cord, rat and human OECs migrated for shorter distances, in both rostral and caudal directions (rat: 762 +/- 118 microm rostral, 554 +/- 142 microm caudal, n = 4; human: 430 +/- 55 microm rostral, 399 +/- 161 microm caudal, n = 3). The results show that rat and human OECs rapidly stop dividing after transplantation and have a similar ability to survive and migrate within the spinal cord of immunocompromised hosts. OECs migrated less in animals with a concomitant contralateral hemisection.