Intraspinal grafting procedures: spinal cord effects induced in the adult rat: a clinical, histopathological, and immunohistochemical study.
Intraspinal grafting procedures using peripheral nerve grafts (PNG) or collagen guidance channels (CGC) have been recently used to treat brachial plexus injuries in humans and spinal cord injuries in animals. This study examined the effects of these procedures in the adult rat. In adult rats, we performed an avulsion of left C5, C6, and C7 nerve roots, followed by a myelotomy of the left ventrolateral aspect of the spinal cord between C5 and C6. The rats were subsequently assigned to one of three groups: group A (n = 10), no additional procedure; group B (n = 10), implantation of a PNG following myelotomy; group C (n = 10), implantation of a CGC. Clinical evaluation was postoperatively assessed. Rats were euthanized at day 6 or 21. Spinal cord lesions induced by surgery were assessed by measuring depth and rostrocaudal extent. Reactive astrogliosis, as a reaction to neuroglial damage, was assessed by revealing the glial fibrillary acidic protein with immunochemistry method. No animal showed persistent neurological deficit at day 21. The depth and rostrocaudal extent of tissue damage was comparable in all groups at days 6 and 21. At day 6, the astrocytic reaction observed at the myelotomy/implantation site was statistically stronger in group C (CGC). At day 21, the astrocytic reaction became identical in all groups. This study shows that grafting a PNG or a CGC into the spinal cord does not create significant additional iatrogenic effects and can be used in repair strategies to treat nerve root avulsions or spinal cord injuries.