Low intensity pulsed ultrasound (LIPUS) has been widely used in clinic for the treatment of repairing pseudarthrosis, bone fractures and of healing in various soft tissues. Some reports indicated that LIPUS accelerated peripheral nerve regeneration including Schwann cells (SCs) and injured nerves. But little is known about its appropriate intensities on autograft nerves. This study was to investigate which intensity of LIPUS improved the regeneration of gold standard postsurgical nerves in experimental rat model. Sprague-Dawley rats were made into 10 mm right side sciatic nerve reversed autologous nerve transplantation and randomly treated with 250 mW/cm2, 500 mW/cm2 or 750 mW/cm2 LIPUS for 2–12 weeks after operation. Functional and pathological results showed that LIPUS of 250 mW/cm2 significantly induced faster rate of axonal regeneration. This suggested that autograft nerve regeneration was improved.
Various
artificial materials have been fabricated as alternatives
to autologous nerve grafts in peripheral nerve regeneration, and these
afford positive recovery effects without the disadvantages of the
gold standard. In this study, we prepared a three-dimensional functionalized
self-assembling peptide nanofiber hydrogel containing two neurotrophic
peptides (CTDIKGKCTGACDGKQC and RGIDKRHWNSQ derived from nerve growth
factor and brain-derived neurotrophic factor, respectively) that reflected
the structure and properties of the neural extracellular matrix. The
material was used to promote axonal regrowth and functional recovery.
Scanning electron microscopy revealed a three-dimensional porous matrix
within the hydrogel. Circular dichroism spectroscopy and atomic force
microscopy confirmed that the peptides displayed a β-sheet structure
and self-assembled into long nanofibers. Rheology measurements and
atomic force microscopy indicated that the elasticity of the peptide
hydrogels was close to that of the nerve tissue matrix. In vitro work
with Schwann cells and dorsal root ganglia showed that the hydrogels
exhibited good cell compatibility. Furthermore, the hydrogel containing
CTDIKGKCTGACDGKQC and RGIDKRHWNSQ promoted the neurite outgrowth of
PC12 cells significantly compared to non-functionalized peptide. In
vivo, the hydrogels were placed into chitosan tubes and used to bridge
10 mm long sciatic nerve defects in rats. We found that the combination
of CTDIKGKCTGACDGKQC and RGIDKRHWNSQ accelerated axonal regeneration
and afforded good functional recovery, suggesting that they synergistically
facilitate peripheral nerve regeneration.
BackgroundPeripheral nerve injury (PNI) is a worldwide issue associated with severe social and economic burden. Autologous nerve grafting, the gold standard treatment for peripheral nerve defects, still has a number of technical limitations. Tissue engineering technology is a novel therapeutic strategy, and mesenchymal stromal cells (MSCs) are promising seed cells for nerve tissue engineering. However, the efficiency of traditional methods for inducing the differentiation of MSCs to Schwann cell-like cells (SCLCs) remains unsatisfactory.MethodsHere, we propose an intermittent induction method with alternate use of complete and incomplete induction medium to induce differentiation of adipose-derived stem cells (ASCs) to SCLCs. The time dependence of traditional induction methods and the efficiency of the intermittent induction method and traditional induction methods were evaluated and compared using immunocytochemistry, quantitative reverse transcription polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and co-culture with the dorsal root ganglion (DRG) in vitro. Cell transplantation was used to compare the effects of the traditional induction method and the intermittent induction method in repairing sciatic nerve defects in vivo.ResultsThe results of the present study indicated that the intermittent induction method is more efficient than traditional methods for inducing ASCs to differentiate into SCLCs. In addition, SCLCs induced by this method were closer to mature myelinating Schwann cells and were capable of secreting neurotrophins and promoting DRG axon regeneration in vitro. Furthermore, SCLCs induced by the intermittent induction method could repair sciatic nerve defects in rats by cell transplantation in vivo more effectively than those produced by traditional methods.ConclusionIntermittent induction represents a novel strategy for obtaining seed cells for use in nerve tissue engineering.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-0884-3) contains supplementary material, which is available to authorized users.
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