Sj. Choi et al., ELECTROPHYSIOLOGICAL, MORPHOLOGICAL, AND MORPHOMETRIC EFFECTS OF AGING ON NERVE REGENERATION IN RATS, Scandinavian journal of plastic and reconstructive surgery and hand surgery, 29(2), 1995, pp. 133-140
To investigate the influence of age on the process of nerve regenerati
on, the right common peroneal nerves of 14 2 month old and 14 10 month
old rats were transected and resutured. At four and eight weeks after
the nerve repair, the motor nerve conduction velocity (MNCV), latency
, and amplitude of the evoked potential from the peroneus longus muscl
e were measured. The number of regenerated myelinated fibres, axon dia
meter, axon area, axon circumference, and myelin thickness were also m
easured. Compared with the control side (left common peroneal nerve an
d muscle), MNCV, latency, and amplitude showed higher recovery rates (
recovery rate (%) = operated/control x 100) in 2 month old rats than i
n 10 month old rats, particularly at four weeks after the operation. I
n the morphometric study, axon diameter, axon area, and myelin thickne
ss also recovered more quickly (recovery rate (%) = operated/control x
100) in 2 month old rats, particularly four weeks after the operation
. Morphologically, myelin remnants were not found in 2 month old rats
eight weeks after the operation, though they remained in 10 month old
rats. These studies show that the recovery rate was significantly grea
ter in 2 month old rats than in 10 month old rats. The explanation see
ms to be the difference in the speed of Wallerian degeneration, axonal
regeneration, and myelin regeneration.