Our previous studies have shown that extracellular vesicles from skin-derived precursor Schwann cells (SKP-SC-EVs) promote neurite outgrowth of sensory and motor neurons in vitro. This study was aimed at generating an artificial nerve graft incorporated with SKP-SC-EVs to examine in vivo effects of SKP-SC-EVs on peripheral nerve regeneration. Here SKP-SC-EVs were isolated and then identified by morphological observation and phenotypic marker expression. Following co-culture with SCs or motoneurons, SKP-SC-EVs were internalized, showing the capability to enhance SC viability or motoneuron neurite outgrowth. In vitro, SKP-SC-EVs released from
Matrigel could maintain cellular uptake property and neural activity. Nerve grafts were developed by incorporating
Matrigel-encapsulated SKP-SC-EVs into
silicone conduits. Functional evaluation, histological investigation, and morphometric analysis were performed to compare the nerve regenerative outcome after bridging the 10-mm long sciatic nerve defect in rats with our developed nerve grafts,
silicone conduits (filled with vehicle), and autografts respectively. Our developed nerve grafts significantly accelerated the recovery of motor, sensory, and electrophysiological functions of rats, facilitated outgrowth and myelination of regenerated axons, and alleviated
denervation-induced
atrophy of target muscles. Collectively, our findings suggested that incorporation of SKP-SC-EVs into nerve grafts might represent a promising paradigm for
peripheral nerve injury repair. STATEMENT OF SIGNIFICANCE: Nerve grafts have been progressively developed to meet the increasing requirements for
peripheral nerve injury repair. Here we reported a design of nerve grafts featured by incorporation of
Matrigel-encapsulated extracellular vesicles from skin-derived precursor Schwann cells (SKP-SC-EVs), because SKP-SC-EVs were found to possess in vitro neural activity, thus raising the possibility of cell-free
therapy. Our developed nerve grafts yielded the satisfactory outcome of nerve grafting in rats with a 10-mm long sciatic nerve defect, as evaluated by functional and morphological assessments. The promoting effects of SKP-SC-EVs-incorporating nerve grafts on peripheral nerve regeneration might benefit from in vivo biological cues afforded by SKP-SC-EVs, which had been released from
Matrigel and then internalized by residual neural cells in sciatic nerve stumps.