Ineffectiveness of enzyme therapy on regeneration in the transected spinal cord of the rat

Abstract

The potential clinical significance of the experiments of Matinian and Andreasian prompted repetition of their experiments. A laminectomy was made at T-5 or T-8 in 92 young female rats, and a fine wire probe was passed beneath the intact cord. The cord was then transected and the probe lifted through the incision so as to ensure the completeness of the transection. Rats were injected with various enzymes of American or Russian manufacture, including trypsin, hyaluronidase, elastase, elastase plus trypsin or vehicle. At autopsy 4-6 mo. later, all rats were paraplegic. The stumps of the spinal cord were separated by cysts and a fibroglial scar. Nerve fibers did not cross the lesion site, nor was there conduction of nerve impulses across the site of injury. There were no significant behavioral, histological or electrophysiological differences between any of the treatment groups. Transection of the spinal cord was then performed in additional animals using Matinian and Andreasian''s original surgical method (without passing a probe beneath the intact cord). Most of these rats began walking within 2-3 wk, without enzyme therapy. Histological analysis revealed intact nerve fibers in the ventrolateral region of the spinal cord, indicating that the spinal cord had not been completely transected. Apparently enzyme treatment neither facilitates nerve regeneration nor permits functional restitution in rats with spinal cord transection and reported findings were apparently the result of incomplete spinal transection.