Platelet-rich plasma (PRP) contains various growth factors and appears to have the potential to promote peripheral nerve regeneration, but evidence is lacking regarding its biological effect on Schwann cells (SCs). The present study was designed to investigate the effect of PRP concentration on SCs in order to determine the plausibility of using this plasma-derived therapy for peripheral nerve injury. PRP was obtained from rats by double-step centrifugation and was characterized by determining platelet numbers and growth factor concentrations. Primary cultures of rat SCs were exposed to various concentrations of PRP (40%, 20%, 10%, 5% and 2.5%). Cell proliferation assays and flow cytometry were performed to study to assess SC proliferation. Quantitative real-time PCR and ELISA analysis were performed to determine the ability of PRP to induce SCs to produce nerve growth factor (NGF) and glial cell line-derived neurotrophic factor (GDNF). Microchemotaxis assay was used to analyse the cell migration capacity. The results obtained indicated that the platelet concentration and growth factors in our PRP preparations were significantly higher than in whole blood. Cell culture experiments showed that 2.5-20% PRP significantly stimulated SC proliferation and migration compared to untreated controls in a dose-dependent manner. In addition, the expression and secretion of NGF and GDNF were significantly increased. However, the above effects of SCs were suppressed by high PRP concentrations (40%). In conclusion, the appropriate concentration of PRP had the potency to stimulate cell proliferation, induced the synthesis of neurotrophic factors and significantly increased migration of SCs dose-dependently. Copyright © 2013 John Wiley & Sons, Ltd.

Acellular nerve allografts (ANAs) behave in a similar manner to autografts in supporting axonal regeneration in the repair of short peripheral nerve defects but fail in larger defects. The objective of this article is to evaluate the effect of ANA supplemented with platelet-rich plasma (PRP) to improve nerve regeneration after surgical repair and to discuss the mechanisms that underlie this approach. Autologous PRP was obtained from rats by double-step centrifugation and was characterized by determining platelet numbers and the release of growth factors. Forty-eight Sprague-Dawley rats were randomly divided into 4 groups (12/group), identified as autograft, ANA, ANA loaded with PRP (ANA+PRP), and ANA loaded with platelet-poor plasma (PPP, ANA+PPP). All grafts were implanted to bridge long-gap (15 mm) sciatic nerve defects. We found that PRP with a high platelet concentration exhibited a sustained release of growth factors. Twelve weeks after surgery, the autograft group displayed the highest level of reinnervation, followed by the ANA+PRP group. The ANA+PRP group showed a better electrophysiology response for amplitude and conduction velocity than the ANA and ANA+PPP groups. Based on histological evaluation, the ANA+PRP and autograft groups had higher numbers of regenerating nerve fibers. Quantitative real-time polymerase chain reaction (qRT-PCR) demonstrated that PRP boosted expression of neurotrophins in the regenerated nerves. Moreover, the ANA+PRP and autograft groups showed excellent physiological outcomes in terms of the prevention of muscle atrophy. In conclusion, ANAs loaded with PRP as tissue-engineered scaffolds can enhance nerve regeneration and functional recovery after the repair of large nerve gaps nearly as well as autografts.

The metaverse has gained popularity recently in many areas including social media, healthcare, education and manufacturing. This work explores the use of the metaverse concept for cultural heritage applications. The motivation is to develop a systematic approach for the construction of a cultural heritage metaverse and to offer, potentially, more effective solutions for tourism guidance, site maintenance, heritage object conservation, etc. We propose a framework for this cultural heritage metaverse with an emphasis on fundamental elements and on characterization of the mapping between the physical and virtual cultural heritage worlds. Efforts are made to analyze the dimensional structures of the cultural heritage metaverse. Specifically, five different dimensions, linearity, planarity, space, time and context, are discussed to better understand this metaverse. The proposed framework and methodology are novel and can be applied to the digitalization of cultural heritage via its metaverse development. This is followed by a detailed case study to illustrate the tangible procedure, constructing a cultural heritage metaverse with a complex and dynamic nature which can be used for different applications, including heritage conservation.

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To establish a model for nerve grafts and determine the anatomic characteristics of the brachial plexus in rhesus monkeys. Ten specimens of the brachial plexus were obtained from five rhesus monkey cadavers. Anatomic dissection of the brachial plexus was systemically performed. The length of each root, trunk, and each division was measured using a Vernier caliper proximodistally. The anatomic distributions of the suprascapular, axillary, and musculocutaneous nerve were documented. The brachial plexus of rhesus monkeys included the spinal nerves or roots of C5, C6, C7, C8, and T1 (80%, 8/10), with a small contribution from the C4 root (20%, 2/10) occasionally. The upper trunk was not measurable because of their irregular structures. The lower trunk had a mean length of 1.62 (range, 0.96-2.1 mm) and a mean diameter of 2.29 (range, 1.9-2.94 mm). For the upper trunk, the C5 and C6 roots either divided into two very short divisions or sent out very long divisions before they joined together. For the middle trunk, the C7 root had a straight course after leaving the foramen and blended imperceptibly into the middle trunk before dividing into the anterior and posterior divisions. The lower trunk was noted in almost all the specimens (80%, 8/10), which was formed by C8 and T1. The brachial plexus in rhesus monkeys varies from that of humans, and defects can be made at the level of C5 and C6 roots and the C7 root should also be cut off and ligated.