Exosomes from Human Gingiva-Derived Mesenchymal Stem Cells Combined with Biodegradable Chitin Conduits Promote Rat Sciatic Nerve Regeneration

Abstract

At present, repair methods for peripheral nerve injury often fail to get satisfactory result. Although various strategies have been adopted to investigate the microenvironment after peripheral nerve injury, the underlying molecular mechanisms of neurite outgrowth remain unclear. In this study, we evaluate the effects of exosomes from gingival mesenchymal stem cells (GMSCs) combined with biodegradable chitin conduits on peripheral nerve regeneration. GMSCs were isolated from human gingival tissue and characterized by surface antigen analysis and in vitro multipotent differentiation. The cell supernatant was collected to isolate the exosomes. The exosomes were characterized by transmission electron microscopy, Western blot, and size distribution analysis. The effects of exosomes on peripheral nerve regeneration in vitro were evaluated by coculture with Schwann cells and DRGs. The chitin conduit was prepared and combined with the exosomes to repair rat sciatic nerve defect. Histology, electrophysiology, and gait analysis were used to test the effects of exosomes on sciatic nerve function recovery in vivo. We have successfully cultured GMSCs and isolated exosomes. The exosomes from GMSCs could significantly promote Schwann cell proliferation and DRG axon growth. The in vivo studies showed that chitin conduit combined with exosomes from GMSCs could significantly increase the number and diameter of nerve fibers and promote myelin formation. In addition, muscle function, nerve conduction function, and motor function were also obviously recovered. In summary, this study suggests that GMSC-derived exosomes combined with biodegradable chitin conduits are a useful and novel therapeutic intervention in peripheral nerve repair.

Dental Stem Cell-Derived Secretome/Conditioned Medium: The Future for Regenerative Therapeutic Applications

“…Although neurodegenerative diseases and other neural insults represent a major challenge as they currently do not have an effective treatment, dental MSC-CM opened the way for treating these challenging conditions. Several studies supported the neuroregenerative effects of dental MSC-CM [66,69,109,110,112,116,[168][169][170]173]. The key role of dental MSC-CM as a modulator of the neurogenic microenvironment is through the release of multiple growth factors promoting neural growth and differentiation like NGF [65,66,110,117]; BDNF [65, 66, 110, 117, 168-170, 173, 176]; NT-3 [65, 110, 168-170, 173, 176]; CNTF, GDNF, and HGF [110]; IGF [117,151]; MFI, MAP-2, β-tubulin III, nestin, and SOX-1 [65], besides Neurofilament 200 and S100 [168][169][170]173].…”

“…In vivo assessment of the repair of a 10 mm defect of the sciatic nerve in rats revealed a significant increase in the thickness of nerve fibers and the myelin sheath. Besides, the muscle and neuromuscular functions were recovered [169]. In an in vitro study, the gingival MSCs derived EVs embedded on locally wrapping gel-foam proved to exert beneficial effects on the functional recovery and axonal repair/regeneration of the crush-injured sciatic nerve in mice.…”

“…Various investigations suggested that gingival MSC-derived EXs, EVs, or CM could represent novel therapeutic interventions in managing peripheral nerve injury [168,169], motor neuron injury [170], and skin [171] and bone defects [172]. The results were comparable with effects conferred by direct transplantation of gingival MSCs [168,169]. The regenerative effect of EXs derived from human gingival MSCs combined with biodegradable chitin conduits on peripheral nerve injury was investigated.…”

“…This finding represents an auspicious application potential for tongue reconstruction in patients suffering from tongue cancer. All these studies propose gingival MSCs' secretome/CM as a simple and autologous therapeutic tool to repair/regenerate nerve injuries, mainly through increasing the expression of anti-inflammatory cytokines (IL-10), antiapoptotic cytokine (Bcl2) [170], and markers denoting neural growth (BDGF, NT-3, Neurofilament 200, S100) [168][169][170]173], as well as enhancing proliferation and regeneration of nerve cells detected by PCNA [168], CCK-8 [169], and Shh [173] aside from a suppression of proinflammatory cytokine TNF-α [170], IL-17, IFN-γ [175,176], and proapoptotic (Bax and cleaved caspase-3) and oxidative stress markers (SOD-1, iNOS, COX-2) [170]. (Table 2).…”

“…Being the primary source of odontoblasts at root region, MSCs from the apical papilla have the ability to differentiate into dentin-pulp complex [198]. MSCs from apical papilla and dental follicle MSCs revealed comparable hepatogenic differentiation potential and superior neurogenic ability to bone marrow MSCs [65,169]. The regenerative potential of human dental pulp MSC-CM, human dental follicle MSC-CM, and human MSCs from apical papilla-CM in nerve [65], liver [64], and bone regeneration [63] was investigated in vitro.…”