ABSTRACT
Combinations of fibroblasts (Fbs) and corresponding epithelial cells have been widely used in many tissues, such as the skin and breast tissues, to augment tissue repair and remodeling. Recently, a large amount of new data has indicated that nerve Fbs play critical roles in Schwann cells (SCs) and axons in vitro. However, little is known regarding the effects of co-transplanting nerve Fbs and SCs on peripheral nerve repair in vivo. The aim of this study was to investigate the effect of co-transplanting sciatic nerve Fbs (SN-Fbs) and sciatic nerve SCs (SN-SCs) on nerve regeneration. We developed a 5 mm nerve-defect model in mice using a polyurethane (PUR) catheter and then injected one of four different mixtures of cells into the catheters to form the following four groups: pure Matrigel (Control group), SN-Fbs alone (SN-Fb group), SN-Fbs combined with SN-SCs at a ratio of 1:2 (Fb&SC group) and SN-SCs alone (SN-SC group). Histological and functional analyses were performed 3 months later. The results indicated that in vitro, the expression levels of NGF, BDNF and GDNF were significantly higher, and in vivo, a more moderate amount of extracellular matrix was produced in the Fb&SC group than in the SN-SC group. Compared to the other groups, co-transplanting SN-Fbs with SCs at a 1:2 ratio had significantly positive effects on nerve regeneration and functional recovery.
Subject(s)
Cell Transplantation , Fibroblasts/cytology , Nerve Regeneration/physiology , Schwann Cells/cytology , Sciatic Nerve/physiology , Animals , Animals, Newborn , Cells, Cultured , Enzyme-Linked Immunosorbent Assay , Female , Fluorescent Antibody Technique , Laminin/metabolism , Male , Mice , Mice, Inbred C57BL , Microscopy, Electron, Transmission , Muscle, Skeletal/metabolism , Polymerase Chain Reaction , Sciatic Nerve/cytology , Sciatic Nerve/metabolismABSTRACT
Schwann cells can be used to promote peripheral nerve repair. However, it is challenging to obtain abundant autologous Schwann cells without sacrificing nerve integrity. In this study, we isolated Schwann cells from murine inguinal adipose tissue and identified the cell phenotype and function in vivo and in vitro. Through H&E and immunofluorescence staining, we detected tiny nerve fibers and Schwann cells in adipose tissue. We evaluated the phenotype of spindle-shaped cells (Schwann cell-like cells, SCLCs) isolated from adipose tissue using immunofluorescence staining and real-time RT-PCR. The results showed that SCLCs expressed specific Schwann cell markers. Analysis of conditioned SCLC culture media showed that, similar to Schwann cells isolated from sciatic nerves, SCLCs secreted NGF and BDNF. SCLCs were harvested from CAG-EGFP transgenic mice and combined with silicone nerve conduits to repair sciatic nerve defects in wild-type mice. Six months post-surgery, we found EGFP-positive SCLCs forming myelin sheaths in the same way as sciatic nerve-derived Schwann cells. This research indicates the existence of Schwann cells in adipose tissue and identifies the spindle-shaped cells isolated from adipose tissue as Schwann cells using in vitro and in vivo evaluations. Thus, SCLCs might be promising seed cells for peripheral nerve tissue engineering.
ABSTRACT
Schwann cells (SCs) in animals exist in different developmental stages or wound repair phases, distinguished mainly by the expression of SC-specific markers. No study has yet determined SC state under in vitro culture conditions, and the specific markers expressed in SC are obscure as well. In this study, we harvested sciatic nerves from newborn mice and isolated SCs by an enzyme-digestion method, then we examined the expression profiles of ten markers (S100, p75NTR, Sox10, Sox2, GAP43, NCAM, Krox20, Oct6, MBP, and MPZ) at both the RNA and protein levels in in vitro mouse SCs and speculated their relation with in vivo SC stages. We assayed RNA and protein levels of SC specific markers by immunofluorescence, Western Blot, and real-time quantitative RT-PCR. The results show that the expression of most markers (S100, p75NTR, GAP43, NCAM, Krox20, Oct6, MBP and MPZ) was not detectable in all of early stage cultured SCs. The expression of transcription factors Sox10 and Sox2 was, however, detectable in all SCs. After 8 days, the positive expression rate of all markers except GAP43 and Oct6 was almost 100%.These results indicates Sox10 is a necessary marker for SC identification, while S100 is not reliable. SCs cultured in vitro express Sox2, P75NTR, NCAM, GAP43, Oct6, and MPZ, suggesting that they are similar to in vivo undifferentiated iSCs or dedifferentiated iSCs after nerve injury.
Subject(s)
Gene Expression , Schwann Cells/metabolism , Animals , Animals, Newborn , Biomarkers , Cells, Cultured , GAP-43 Protein/genetics , GAP-43 Protein/metabolism , Gene Expression Profiling , Mice , Myelin Basic Protein/genetics , Myelin Basic Protein/metabolism , Myelin P0 Protein/genetics , Myelin P0 Protein/metabolism , Neural Cell Adhesion Molecules/genetics , Neural Cell Adhesion Molecules/metabolism , Phenotype , Receptor, Nerve Growth Factor/genetics , Receptor, Nerve Growth Factor/metabolism , S100 Proteins/genetics , S100 Proteins/metabolism , Sciatic Nerve/metabolism , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Autologous tissues such as skeletal muscle have high biocampatibility and can effectively promote nerve regeneration compared to other biological and artificial materials; however, the reasonable and effective application of skeletal muscle requires further study. The purpose of this investigation was to assess the possibility of preparing a hollow nerve conduit, termed the epimysium conduit (EMC), using thin crimps of epimysium with skeletal muscle fibers and evaluate its effectiveness in repairing peripheral nerve defects. We prepared nerve conduits containing lumen with the external oblique muscle of the CAG-EFGP transgenic mice using microsurgical techniques for bridge repair of a 5-mm long sciatic nerve defect in wild-type mice. Systematic histological and functional assessments of the regenerated nerves were performed 8 and 12 weeks after surgery. EMC was found to effectively repair the sciatic nerve defect with significantly greater effectiveness than artificial conduits; however, the repair effect of EMC was lower than that of autologous nerve grafting for some parameters. In addition, our findings showed that some EMC-derived cell components migrated into the region of the regenerated nerves and contributed to reconstruction. Based on these findings, we conclude that a hollow conduit prepared with epimysium and a few skeletal muscle fibers is ideal for repairing peripheral nerve defects, and the cell components in the grafts contribute to nerve regeneration and structural remodeling, which provides an alternative option for the emergency primary repair of peripheral nerve defects in clinical practice.
Subject(s)
Nerve Regeneration/physiology , Peripheral Nerves/pathology , Tissue Scaffolds/chemistry , Wound Healing , Action Potentials/physiology , Animals , Female , Fluorescent Antibody Technique , Green Fluorescent Proteins/metabolism , Mice , Mice, Inbred C57BL , Muscles/pathology , Muscles/surgery , Peripheral Nerves/surgery , Peripheral Nerves/ultrastructure , Tolonium Chloride/metabolismABSTRACT
In the present study, Schwann cells were isolated from the sciatic nerve of neonatal mice and purified using dispase and collagenase. Results showed that after the first round of purification with dispase, most of the Schwann cells appeared round in shape and floated in culture solution after 15 minutes. In addition, cell yield and cell purity were higher when compared to the collagenase group. After the second round of purification, the final cell yield for the dispase group was higher than that for the collagenase group, but no significant difference was found in cell purity. Moreover, similar results in cell quantity and purity were observed in adult Sprague-Dawley rats. These findings indicate that purification with dispase can result in the rapid isolation of Schwann cells with a high yield and purity.
