The effectiveness of denatured autologous muscle grafts for nerve repair in an experimental model of leprosy was assessed. Nerve damage resembling that caused by Mycobacterium leprae in humans was induced by the injection of cobalt-irradiated M. leprae into the tibial nerve of guinea pigs. At the time of maximum functional loss, caused by the formation of a granuloma within the nerve, the area of damage was excised and a denatured autologous muscle graft was used to repair the nerve. Assessment of nerve regeneration through the graft was made using clinical, electrophysiological and microscopic morphometric analysis at intervals up to 20 weeks. The results were compared with regeneration after grafting of a normal nerve. Clinically, some motor and sensory recovery occurred in all of the graft recipients in the normal nerve by 8 weeks, and by 11 weeks in the recipients of grafts in the granulomatous nerve. Full sensory recovery occurred in all but one animal by 20 weeks. Motor function recovered to near normal levels at 14 weeks after repair of the normal nerve but, at 20 weeks, there was variation in motor recovery after repair of the granulomatous nerve. Electrophysiology showed increased conduction velocity of the nerve fibers at each timepoint. The conduction velocity at 8 weeks after grafting of the normal nerve was similar to that at 12 weeks after grafting of the granulomatous nerve. Morphometry showed an increasing number of myelinated fibers repopulating the distal nerve up to 20 weeks. Myelin fiber numbers, at this time, were one third of normal after repair of the granulomatous nerve and two thirds after repair of the normal nerve. This study demonstrates that denatured autologous muscle grafts enable the regeneration and functional recovery of nerves despite their being damaged by mycobacteria-induced granulomas, but the damage causes some delay.
|Number of pages||9|
|Journal||International Journal of Leprosy|
|Publication status||Published - 1994|