Progress of Regeneration and Repair Mechanism After Peripheral Nerve Injury

Peripheral nerve injury(PNI)is a disease in which peripheral nerve cells are damaged or necrotic due to compression, traction, cutting and ischemia. Pathological changes of peripheral nerve injury include impaired axoplasmic transport, axonal degeneration, schwann cell injury, segmental demyelination and complete Waller'sdegeneration. Autogenous nerve transplantation(ANT)is the gold standard for treatment of large peripheral nervedefects(>1cm in rats and >3cm in humans).In addition to autologous transplantation, stem cell transplantationwill promote peripheral nerve regeneration,improve myelin sheath formation and nerve survival.Neurotrophicfactors include nerve growth factor(NGF),glial cell line-derived neurotrophic factor(GDNF),brain-derivedneurotrophic factor(BDNF)can promote neuronal differentiation,axon growth and synaptic connection.Newbiomaterials including chitosan scaffold(CS),silk fibroin(SF),3-hydroxyoctanoic acid co-3-hydroxydecanoicacid/polycaprolactone(P(3HO-3HD)/PCL75/25)or acellular cauda equina allograft(ACEA)can support andguide the growth of axon. Combined with3D printing technology, personalized neural conduits can be designed and manufactured. Electroacupuncture stimulation of Huan-jump point(GB30)and Zusanli point(ST36)can prevent apoptosis of neurons and promote the growth of axon. The combination of several materials and formation of tissue engineered nerve graft(TENG),will have better effects on repairing of nerve injury. Thus, the role and mechanisms of these methods in the repair of peripheral nerve injury were reviewed, and their clinical application was prospected