Comparison of chemotaxis during the peripheral nerve regeneration in rats of different ages / 中华创伤骨科杂志

ABSTRACT

Objective To compare the differences of chemotaxis at the tissue specific level and topographic specificity level during peripheral nerve regeneration after the severance injury of the sciatic nerve in rats of different ages. Methods 40 specific pathogen free Sprague Dawley 18 day old rats (called as young group) were chosen to correspond as nearly as possible to humans of about 1 year of age. 40 adult rats (called as adult group) were chosen to correspond as adult humans. The tissue and topographic specificity models were set up respectively after the severance of the sciatic nerve at the right side. Electromyography and morphological evaluations were conducted for determination of the nerve regeneration on 3 and 6 weeks postoperatively. Results On 3 and 6 weeks after operation, the recovery rate of nerve conduction velocity, the exact rate of nerve regeneration, the ratio of nerve conduction velocity between tibial and peroneal nerve, the ratio of amplitude of CMAP between tibial and peroneal nerve, the ratio of the number of myelinated axon between the tibial and peroneal nerve at the distal part in the young group were lower than those in the adult group respectively. There were statistically significant differences between the 2 groups. The recovery rate of amplitude in compound muscle action potential (CMAP) was lower in the young group than in the adult group, but the difference was not significant enough. Conclusion Since the tissue and topographic specificities in the young rats are both inferior to those in the adult rats, co contraction between agonists and antagonists may result from cross innervation during the peripheral nerve regeneration.