RESUMO
Objective This study is to identify long-term functional recovery and maturity of regenerated nerve fibers after repairing mouse nerve defects with chitosan/polylactide-co-polyglycolide artificial nerve grafts ( CPANGs ) . Methods Mouse sciatic nerve defects, 2mm in length, were bridged by CPANGs (n=6), with nerve autograft (n=6) and nerve defect (n=6) as controls.Plantar test, electrophysiological examination and laser Doppler perfusion imaging following nerve crush were carried out at 1 year after repair to assess nerve function recovery , while muscle wet weight ratio, histological assessment and transmission electron microscopy were performed to evaluate nerve re -innervation and maturity of regenerated nerve fibers .Results When compared to the autograft group , the CPANG group did not show statistically significant difference in functional recovery in terms of paw withdrawal latency , neurogenic vasodilatation , amplitude and latency of compound muscle action potentials ( CMAPs ) , wet weight ratio of gastrocnemius and tibialis cranialis muscles , number of myelinated nerve fibers and density of unmyelinated axons .However , both these two repair groups exhibited significantly longer CMAPs latency , thinner myelin sheath and a lag-behind shift of diameter distribution of myelinated axons as compared to the normal control .Conclusion At 1 year after the mouse sciatic nerve defect was repaired by CPANGs , sensory and autonomic nerve function , number of regenerated axons and muscle re-innervation degree were recovered to the same extent as nerve autografting , but the regenerated nerve fibers were in a state of immaturity .