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Approximately 80% of amputations are complicated by neuromas. Methods for neuroma management include nerve translocation into bone and implantation into skeletal muscle grafts, which have also facilitated the development of regenerative neural interfaces to enable fixation of prosthetics with motor and sensory feedback. However, molecular-level differences between nerves in these environments have not been investigated. This study aimed to elucidate the physiology of regenerating nerves in different settings by assessing gene expression. New Zealand white rabbits underwent transfemoral amputation with sciatic nerve transposition into the femur or tacked to skeletal muscle. At 5 wk, ribonucleic acid (RNA) sequencing of samples of distal nerve terminating in bone or muscle and nerve of the contralateral limb (control) identified differentially expressed genes (DEGs) and biochemical pathways (α = 0.05). Three samples of nerve housed in bone, four of nerve tacked to muscle, and seven naïve controls were analyzed. Relative to controls, nerve housed in bone had little within-group variation and 13,028 DEGs, and nerve tacked to muscle had dramatic within-group variation and 12,811 DEGs. These samples upregulated the following pathways: lysosome, phagosome, antigen processing/presentation, and cell adhesion molecule. Relative to nerve housed in bone, nerve tacked to muscle had 12,526 DEGs, demonstrating upregulation of pathways of B-cell receptor signaling, focal adhesion, natural killer–cell mediated cytotoxicity, leukocyte transendothelial migration, and extracellular matrix–receptor interactions. Nerve housed in bone has a more predictable molecular profile than does nerve tacked to muscle. Thus, the intramedullary canal may provide a more reliable setting for neuroma prevention and neural interfacing. [ABSTRACT FROM AUTHOR]

BACKGROUND: Platelet-rich plasma (PRP) contains growth factors that affect tendon, ligament, muscle and bone hesling. On this basis, researchers gradually realize that such molecules released after PRP activation can regulate the early inflammation of peripheral nerve injury, activate Schwann cells, promote the polarization of macrophages, and actively prevent the hyperplasia of collagen fibers, thus becoming the key drivers of nerve function recovery. OBJECTIVE: To evaluate the value of ultrasound-guided PRP injection in the repair of sciatic nerve crush injury. METHODS: Twenty-eight heslthy New Zealand white rabbits provided by the Beijing Longan Experimental Animal Breeding Center) were randomly divided into normal group, control group, single PRP group and multiple PRPs group. In the normal group, the right sciatic nerve was exposed and then sutured directly. In the control group, a compression injury model of the right sciatic nerve was established. In the single PRP group, autologous PRP was injected around the injured nerve under ultrasound guidance at 24 hours after modeling. In the multiple PRPs group, autologous PRP was injected around the injured nerve under ultrasound guidance at 24 hours after modeling, and then the PRP injection was performed once at the 3rd and 5th weeks after modeling. Histological and morphological observation of regenerated nerves, wet weight recovery and histological manifestations of the denervated muscle were evaluated at 12 weeks after modeling. The study protocol was approved by the Administrative Committee of Experimental Animals in PLA General Hospital with the approval No. 2015-x10-02. RE SUL TS AND CONCLUSION: The integral optical density values of NF-200 and S 100 staining, myelinated nerve fiber density, myelinated nerve fiber diameter and myelin sheath thickness were significantly increased in the single PRP and multiple PRPs groups compared with the control group (all P < 0.05), and the multiple PRPs group showed better outcomes than the single PRP group {all P < 0.05), but was still inferior to the normal group (all P < 0.05). Compared with the control group, wet weight and cross-sectional area of muscle fibers significantly increased in the single PRP group and multiple PRPs group (P < 0.05), and the multiple RPRs group showed better outcomes than the single PRP group, but was still inferior to the normal group (P < 0.05). To conclude, ultrasound-guided multi-frequency injection of autologous PRP has a good effect on the repair of sciatic nerve crush injury. [ABSTRACT FROM AUTHOR]