Fig. 18

Schematic diagram of peripheral nerve defect repair using autogenous vein grafts filled with PRP and active nerve microtissues. After nerve injury, SCs recruit macrophages to facilitate the removal of myelin axonal remnants. At the same time, hypoxia within the bridge is selectively sensed by macrophages, which secrete VEGF-A to induce the formation of polarized vasculature in the bridge area. Nerve microtissues could be decomposed into a large number of SCs, which could secrete a large quantity of neurotrophic factors to promote the generation of blood vessels and the proliferation and migration of SCs. However, SCs showed a limited proliferative capacity. The addition of PRP may remedy this limitation. PRP, which contains various growth factors that are associated with peripheral nerve regeneration, can further stimulate SCs play the above roles in different ways. Thus promoting axon extension along the Büngner brand, and the SCs complete the nerve regeneration process by remyelinating the newly formed axons