Collagen implants to promote regeneration of the adult rat spinal cord

Abstract

Over 250,000 people in the United States currently live with a spinal cord injury and approximately 11,000 new cases occur every year. People with spinal cord injuries experience a significant reduction in quality of life due to the many problems that arise from damage to the spinal cord including paralysis and loss of sensation below the location of injury, loss of bowel and bladder function, loss of sexual function, and impaired respiration. Despite considerable ongoing research in the area of nerve regeneration by various institutions, satisfactory treatment for spinal cord injury has not yet been discovered. Previous studies have had considerable success in facilitating the regeneration of severed peripheral nerves through the use of collagen based implants used to bridge the resulting gap between the severed nerve stumps. The current study aims to apply this same regenerative approach to a defect created in the spinal cord of adult rats. The objective is to evaluate the efficacy of three different collagen implants toward the regeneration of the spinal cord. The experimental spinal cord injury was a complete transection at T7 and T9 and the removal of the spinal cord segment between the two transections, creating a 5 mm gap.

(cont.) This study contained four experimental groups. Group I was the control group. The animals in this group had a complete spinal cord transection as described above but received no implantation. Group II received a resorbable dura replacement sheet of collagen, 1 mm thick, cut from the BioGide(® membrane which was placed extradurally over the dorsal aspect of the wound site. Group III used the BioGide® membrane as a wrap which bridged the gap between the two cord stumps. Group IV used a collagen tube, fabricated using a freeze-drying process, to bridge the gap. Histological analysis at 6 weeks after implantation showed Groups III and IV to have more longitudinally oriented reparative tissue filling the defect area as well as fewer fluid-filled cysts. Quantitative analysis of axonal regeneration showed the collagen implants to be supportive of the regeneration of axons into the center of the defect.