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Comparison of dorsal and ventral spinal root regeneration through semipermeable guidance channels
Author(s) -
McCormack M. L.,
Goddard M.,
Guéanard V.,
Aebischer P.
Publication year - 1991
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903130305
Subject(s) - dorsal root ganglion , anatomy , dorsum , biology , regeneration (biology) , microbiology and biotechnology
Abstract Semipermeable guidance channels have been shown to support nerve regeneration in the peripheral nervous system (PNS) possibly through interactions with the wound healing environment. This study quantitatively assesses the ability of such channels to support regeneration in the PNS segment of the spinal roots across a 4 mm gap and compares the resultant dorsal and ventral root regeneration. Acrylic copolymer guidance channels with a molecular weight ( Mw ) cutoff of 50,000 Da were used in a transected rat spinal root model. Cohorts of 23 animals (11 ventral, 12 dorsal) were examined at four weeks; 6 animals (3 ventral, 3 dorsal) at ten weeks; and 10 animals (5 ventral, 5 dorsal) at twenty‐four weeks post‐implantation. Both the dorsal and ventral roots were able to regenerate across the gap within the semipermeable channel. At all time periods, the regenerated dorsal roots contained fewer myelinated axons than found in the contralateral control root and consisted of an abundance of collagenous tissue. In contrast, by ten weeks the regenerated ventral roots contained twice the contralateral control number of myelinated axons and were composed predominantly of large, myelinated axons. At twenty‐four weeks the number of unmyelinated axons was also quantified, with the regenerated dorsal root containing only one‐fifth of the control number and the regenerated ventral root containing more than four times the control. Due to the proximity of the dorsal root lesion to the axonal cell bodies, the dorsal root ganglion (DRG) neuronal cell loss was investigated at four weeks post‐implantation. A comparison of the cell numbers on the experimental side to those on the contralateral control side yielded a mean E/C ratio of 1.07, suggesting that a significant cell loss is an unlikely causative factor in the impairment of regeneration in the dorsal root. This study reports a difference in the regenerative capacities of dorsal and ventral roots using semipermeable guidance channels. Future studies involving variations in the regenerative environment may help determine the factors responsible for the different regenerative capabilities of the spinal roots.