Objective To construct chemically extracted acellular nerve allograft (CEANA) with Schwann cells (SCs) from different tissues and to compare the effect of repairing peripheral nerve defect. Methods Bone marrow mesenchymal stem cells (BMSCs) and adi pose-derived stem cells (ADSCs) were isolated and cultured from 3 4-week-old SD mice with weighing 80-120 g. BMSCs and ADSCs were induced to differentiated MSC (dMSC) and differentiated ADSC (dADSC) in vitro.dMSC and dADSC were identified by p75 protein and gl ial fibrillary acidic protein (GFAP). SCs were isolated and culturedfrom 10 3-day-old SD mice with weighing 6-8 g. CEANA were made from bilateral sciatic nerves of 20 adult Wistar mice with weighing 200-250 g. Forty adult SD mice were made the model of left sciatic nerve defect (15 mm) and divided into 5 groups (n=8 per group) according to CEANA with different sources of SCs: autografting (group A), acellular grafting with SCs (5 × 105) (group B), acellular grafting with dMSCs (5 × 105) (group C), acellular grafting with dADSCs (5 × 105) (group D), and acellular grafting alone (group E). Motor and sensory nerve recovery was assessed by Von Frey and tension of the triceps surae muscle testing 12 weeks after operation. Then wet weight recovery ratio of triceps surae muscles was measured and histomorphometric assessment of nerve grafts was evaluated. Results BMSCs and ADSCs did not express antigens CD34 and CD45, and expressed antigen CD90. BMSCs and ADSC were differentiated into similar morphous of SCs and confirmed by the detection of SCs-specific cellsurface markers. The mean 50% withdrawal threshold in groups A, B, C, D, and E was (13.8 ± 2.3), (15.4 ± 6.5), (16.9 ± 5.3), (16.3 ± 3.5), and (20.0 ± 5.3) g, showing significant difference between group A and group E (P lt; 0.01). The recovery of tension of the triceps surae muscle in groups A, B, C, D, and E was 87.0% ± 9.7%, 70.0% ± 6.6%, 69.0% ± 6.7%, 65.0% ± 9.8%, and 45.0%± 12.1%, showing significant differences between groups A, B, C, D, and group E (P lt; 0.05). No inflammatory reactionexisted around nerve graft. The histological observation indicated that the number of myel inated nerve fiber and the myel in sheath thickness in group E were significantly smaller than that in groups B, C, and D (P lt; 0.01). The fiber diameter of group B was significantly bigger than that of groups C and D (P lt; 0.05) Conclusion CEANA supplementing with dADSC has similar repair effect in peripheral nerve defect to supplementing with dMSC or SCs. dADSC, as an ideal seeding cell in nerve tissue engineering, can be benefit for treatment of peripheral nerve injuries.
ObjectiveTo systemically review the efficacy and safety of Schwann cells (SCs) or activated Schwann cells (ASCs) transplantation in the treatment of traumatic spinal-cord injury (TSCI) in rats models. MethodsRandomized controlled trials (RCTs) about the effects of SCs and ASCs transplantation for TSCI in rats were searched in PubMed, EMbase, The Cochrane Library (Issue 12, 2014), CBM, CNKI, WanFang Data and VIP from inception to December 2014. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed the risk of bias of included studies. Then meta-analysis was performed using RevMan 5.3 software. ResultsA total of 14 RCTs involving 510 rats were included. The results of meta-analysis showed that:compared with the control group, the Basso, Beattie and Bresnahan (BBB) scores in the SCs or ASCs transplantation group were superior in 4 weeks (SMD=2.31, 95%CI 1.48 to 3.13, P<0.000 01), 8 weeks (SMD=3.93, 95%CI 3.06 to 4.81, P<0.000 01) and 12 weeks (SMD=6.15, 95%CI 4.30 to 8.00, P<0.000 01) after surgery. The BBB scores in the SCs or ASCs transplantation combined with other therapies group were also better in 4 weeks (SMD=1.06, 95%CI 0.44 to 1.68, P=0.000 8), 8 weeks (SMD=2.26, 95%CI 1.57 to 2.96, P<0.000 01) and 12 weeks (SMD=1.49, 95%CI 0.72 to 2.25, P<0.000 01) after surgery. Compared with the SCs group, the BBB score in the ASCs transplantation group were superior in 4 weeks (SMD=4.31, 95%CI 3.50 to 5.13, P<0.000 01) and 12 weeks (SMD=5.44, 95%CI 3.99 to 6.89, P<0.000 01) after surgery. No significant difference was found in mortality between the transplantation group and the control group. ConclusionCurrent evidence indicates that SCs and ASCs can promote the recovery of motor function in the rats with TSCI. More functional recoveries can be obtained in ASCs transplantation compared with SCs transplantation. Due to limited quality of the included studies, the above conclusion should be verified by conducting more large-scale, high quality RCTs.
Objective To review the research progress on the role of Schwann cells in regulating bone regeneration. MethodsThe domestic and foreign literature about the behavior of Schwann cells related to bone regeneration, multiple tissue repair ability, nutritional effects of their neurotrophic factor network, and their application in bone tissue engineering was extensively reviewed. ResultsAs a critical part of the peripheral nervous system, Schwann cells regulate the expression level of various neurotrophic factors and growth factors through the paracrine effect, and participates in the tissue regeneration and differentiation process of non-neural tissues such as blood vessels and bone, reflecting the nutritional effect of neural-vascular-bone integration. ConclusionTaking full advantage of the multipotent differentiation ability of Schwann cells in nerve, blood vessel, and bone tissue regeneration may provide novel insights for clinical application of tissue engineered bone.
Objective Inducing human amniotic membrane mesenchymal stem cells (hAMSCs) to Schwann cells-like cells (SCs-like cells) in vitro, and to evaluate the efficacy of transplantation of hAMSCs and SCs-like cells on nerves regeneration of the rat flaps. Methods hAMSCs were isolated from placenta via two-step digestion and cultured by using trypsin and collagenase, then identified them by flow cytometry assay and immunofluorescence staining. The 3rd generation of hAMSCs cultured for 6 days were induced to SCs-like cells in vitro; at 19 days after induction, the levels of S-100, p75, and glial fibrillary acidic protein (GFAP) were detected by immunofluorescence staining, Western blot, and real-time fluorescence quantitative PCR (qPCR). The levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were measured by ELISA in the supernatant of the 3rd generation of hAMSCs cultured for 6 days and the hAMSCs induced within 19 days. In addition, 75 female Sprague Dawley rats were taken to establish the rat denervated perforator flap model of the abdominal wall, and were divided into 3 groups (n=25). The 3rd generation of hAMSCs (1×106 cells) in the proliferation period of culturing for 6 days, the SCs-like cells (1×106 cells), and equal volume PBS were injected subcutaneously in the skin flap of the rat in groups A, B, and C, respectively. At 2, 5, 7, 9, and 14 days after transplantation, 5 rats in each group were killed to harvest the flap frozen sections and observe the positive expression of neurofilament heavy polypeptide antibody (NF-01) by immunofluorescence staining. Results The cells were identified as hAMSCs by flow cytometry assay and immunofluorescence staining. The results of immunofluorescence staining, Western blot, qPCR showed that the percentage of positive cells, protein expression, and gene relative expression of S-100, p75, and GFAP in SCs-like cells group were significantly higher than those in hAMSCs group (P<0.05). The results of ELISA demonstrated that the expression of BDNF and NGF was significantly decreased after added induced liquid 1, and the level of BDNF and NGF increased gradually with the induction of liquids 2 and 3, and the concentration of BDNF and NGF was significantly higher than that of hAMSCs group (P<0.05). Immunofluorescence staining showed that the number of regenerated nerve fibers in group B was higher than that in groups A and C after 5-14 days of transplantation. Conclusion The hAMSCs can be induced into SCs-like cells with the proper chemical factor regulation in vitro, and a large number of promoting nerve growth factor were released during the process of differentiation, and nerve regeneration in flaps being transplanted the SCs-like cells was better than that in flaps being transplanted the hAMSCs, which through a large number of BDNF and NGF were released.
ObjectiveTo establish an efficient method of isolating and culturing high activity and high purity of Schwann cells, and to identify the cells at the levels of transcription and translation. MethodsThe sciatic nerves harvested from a 4-week-old Sprague Dawley rat were digested in the collagenase I for 15 minutes after dissecting, and then the explants were planted in culture flask directly. The cells were cultured and passaged in vitro, the growth state and morphological changes of the cells were observed under inverted phase contrast microscope. MTT assay was used to test the proliferation of cells and the cells growth curve was drawn. RT-PCR and immunohistochemistry staining were used to detect S100 and glial fibrillary acidic protein (GFAP) at the levels of transcription and translation, respectively. The purity of cells was caculated under microscope. ResultsAfter the digestion of collagenase I, fibroblast-like cells appeared around explants within 24 hours, with slender cell body and weak refraction. After tissues were transferred to another culture flask, a large number of dipolar or tripolar cells were seen after 48 hours, with slender ecphyma, plump cell body, and b refraction, and the cells formed colonies within 72 hours. The cells were covered with the bottom of culture flask within 48-72 hours after passaging at a ratio of 1∶2, and spiral colonies appeared. Cells showed vigorous growth and full cytoplasm after many passages. MTT assay results showed that the cells at passage 3 entered the logarithmic growth phase on the 3rd day, reached the plateau phase on the 7th day with cell proliferation, and the growth curve was “S” shape. RT-PCR results showed that the cells expressed S100 gene and GFAP gene, and immunohistochemistry staining showed that most of the cells were positively stained, indicating that the majority of cells expressing S100 protein and GFAP protein. The purity of Schwann cells was 98.37% ± 0.30%. ConclusionHigh activity and high purity of Schwann cells can be acquired rapidly by single-enzyme digestion and explant-culture method.
Objective To study the effects of neonatol rabbit Schwann cells(SC) on repair of optic contusion in adult rabbits. Methods 24 h after the adult rabbit optic nerves was contused,0.1 ml of SC suspension (group A) and saline water (group B) were injected into the vitreous of injured eyes respectively.All the animals were studied by retinal ganglion cell (RGC) and axon counting,flash visual evoked potential (FVEP) tests at various intervals after injury. Results At the 4th week after injury,the number of RGC was (19.89plusmn;3.79)/mm in group A and (12.67plusmn;4.12)/mm in group B,and the density of axons was (94.569plusmn;793)/mm2 in group A and (36.085plusmn;285)/mm2 in group B.There was dramatical difference between group A and B (Plt;0.01).The amplitude of FVEP wave of group A increased from 48% to 88% on the 3rd day after injury,and still dept 78% at the 8th week and group A was significantly higher than group B at various intervals (Plt;0.01). Conclusion SC are effective in promoting the repair of optic nerve contusion by increasing the survival rate of RGC,rescuing axons from degeneration,and dramatically promoting the function of the optic nerve. (Chin J Ocul Fundus Dis,2000,16:91-93)
ObjectiveTo summarize the applications of Schwann cells (SCs), stem cells, and genetically modified cells (GMCs) in repair of peripheral nerve defects. MethodsThe literature of original experimental study and clinical research related with SCs, stem cells, and GMCs was reviewed and analyzed. ResultsSCs play a key role in repair of peripheral nerve defects; the stem cells can be induced to differentiate into SCs, which can be implanted into nerve conduits to promote the repair of peripheral nerve defect; genetically modified technology can enhance the function of SCs and different stem cells, which has been regarded as a new option for tissue engineered nerve. ConclusionAlthough great progress has been made in tissue engineered nerve recently, mostly limited to the experimental stage. The research of seed cells in application of tissue engineered nerve need be studied deeply.
ObjectiveTo investigate the protective effects of carboxymethylated chitosan (CMCS) on oxidative stress induced apoptosis of Schwann cells (SCs), and the expressions of brain derived neurotrophic factor (BDNF) and gl ial cell line derived neurotrophic factor (GDNF) in oxidative stress induced SCs. MethodsTwenty-four 3-5 days old Sprague Dawley rats (weighing 25-30 g, male or female) were involved in this study. The bilateral sciatic nerves of rats were harvested and SCs were isolated and cultured in vitro. The purity of SCs was identified by immunofluorescence staining of S-100. SCs were treated with different concentrations of hydrogen peroxide (H2O2, 0.01, 0.10, and 1.00 mmol/L) for 3, 6, 12, and 24 hours to establ ish the apoptotic model. The cell counting kit 8 (CCK-8) and flow cytometry analysis were used to detect the cell viabil ity and apoptosis induced by H2O2, and the optimal concentration and time for the apoptotic model of SCs were determined. The 2nd passage SCs were divided into 5 groups and were treated with PBS (control), with 1.00 mmol/L H2O2, with 1.00 mmol/L H2O2+50 μg/mL CMCS, with 1.00 mmol/L H2O2+100 μg/mL CMCS, and with 1.00 mmol/L H2O2+200 μg/mL CMCS, respectively. After cultured for 24 hours, the cell viabil ity was assessed by CCK-8, cell apoptosis was detected by flow cytometry analysis, the expressions of mRNA and protein of BDNF and GDNF were detected by real-time quantitative PCR and Western blot. ResultsThe immunofluorescence staining of S-100 indicated the positive rate was more than 95%. CCK-8 and flow cytometry results showed that H2O2 can inhibit the proliferation of SCs and induce the SCs apoptosis with dose dependent manner, the effect was the most significant at 1.00 mmol/L H2O2 for 24 hours; after addition of CMCS, SCs exhibited the increased proliferation and decreased apoptosis in a dose dependent manner. Real-time quantitative PCR and Western blot analysis showed that 1.00 mmol/L H2O2 can significantly inhibit BDNF and GDNF expression in SCs when compared with control group (P<0.05), 50-200 μg/mL CMCS can reverse the oxidative stress-induced BDNF and GDNF expression in SCs in a dose dependent manner, showing significant difference compared with control group and 1.00 mmol/L H2O2 induced group (P<0.05). There were significant differences among different CMCS treated groups (P<0.05). ConclusionCMCS has the protective stress on oxidative stress induced apoptosis of SCs, and may promote the BDNF and GDNF expressions of neurotrophic factors in oxidative stress induced SCs.
Objective To obtain highly purified and large amount of Schwann cells (SCs) by improved primary culture method, to investigate the biocompatibility of small intestinal submucosa (SIS) and SCs, and to make SIS load nerve growth factor (NGF) through co-culture with SCs. Methods Sciatic nerves were isolated from 2-3 days old Sprague Dawley rats and digested with collagenase II and trypsin. SCs were purified by differential adhesion method for 20 minutes and treated with G418 for 48 hours. Then the fibroblasts were further removed by reducing fetal bovine serum to 2.5% in H-DMEM. MTT assay was used to test the proliferation of SCs and the growth curve of SCs was drawn. The purity of SCs was calculated by immunofluorescence staining for S-100. SIS and SCs at passage 3 were co-cultured in vitro. And then the adhesion, proliferation, and differentiation of SCs were investigated by optical microscope and scanning electron microscope (SEM). The NGF content by SCs was also evaluated at 1, 2, 3, 4, 5, and 7 days by ELISA. SCs were removed from SIS by repeated freeze thawing after 3, 5, 7, 10, 13, and 15 days of co-culture. The NGF content in modified SIS was tested by ELISA. Results The purity of SCs was more than 98%. MTT assay showed that the SCs entered the logarithmic growth phase on the 3rd day, and reached the plateau phase on the 7th day. SCs well adhered to the surface of SIS by HE staining and SEM; SCs were fusiform in shape with obvious prominence and the protein granules secreted on cellular surface were also observed. Furthermore, ELISA measurement revealed that, co-culture with SIS, SCs secreted NGF prosperously without significant difference when compared with the control group (P gt; 0.05). The NGF content increased with increasing time. The concentration of NGF released from SIS which were cultured with SCs for 10 days was (414.29 ± 20.87) pg/cm2, while in simple SIS was (4.92 ± 2.06) pg/cm2, showing significant difference (P lt; 0.05). Conclusion A large number of highly purified SCs can be obtained by digestion with collagenase II and trypsin in combination with 20-minute differential adhesion and selection by G418. SIS possesses good biocompatibility with SCs, providing the basis for further study in vivo to fabricate the artificial nerve conduit.
ObjectiveTo review the research advance of differentiation of induced pluripotent stem cells (iPS) into Schwann cells in vitro in recent years. MethodsRelated literatures on differentiation of iPS into Schwann cells in vitro at present were consulted, the induction methods of iPS differentiating into Schwann cells in vitro were summarized, and the differentiated cells were identified and detected. ResultsThe research results indicate that iPS can differentiate into Schwann cells. So far, the iPS have to differentiate into neural crest cells or neural crest stem cells firstly, and then differentiate into Schwann cells. S100-β and glial fibrillary acidic protein (GFAP) are recognized as the marker of Schwann cells. The evidence of generating Schwann cells was that the neural crest cells or neural crest stem cells were labelled by p75+, HNK1+, or nestin+ before differentiation, and by S100-β+ and GFAP+ after induction. ConclusionDespite the increasing reported studies of Schwann cells from iPS, there have been few successful induction methods, so this field of cytology needs further study.