OBJECTIVE: To review the research progress on silk fibroin (SF)-nerve guidance conduits (NGCs) for peripheral nerve injury (PNI) repair. METHODS: To review the recent literature on PNI and SF-NGCs, expound the concepts and treatment strategies of PNI, and summarize the construction of SF-NGCs and its application in PNI repair. RESULTS: Autologous nerve transplantation remains the "gold standard" for treating severe PNI. However, it's clinical applications are constrained by the limitations of limited donors and donor area damage. Natural SF exhibits good biocompatibility, low immunogenicity, and excellent physicochemical properties, making it an ideal candidate for the construction of NGCs. SF-NGCs constructed using different technologies have been found to have better biocompatibility and bioactivity. Their configurations can facilitate nerve regeneration by enhancing regenerative guidance and axonal extension. Besides, the adhesion, proliferation and differentiation of neurons and Schwann cells related to PNI repair can be effectively promote by NGCs. This accelerates the speed of nerve regeneration and improves the efficiency of repair. In addition, SF-NGCs can be used as regenerative scaffolds to provide biological templates for nerve repair. CONCLUSION The biodegradable natural SF has been extensively studied and demonstrated promising application prospects in the field of NGCs. It might be an effective and viable alternative to the "gold standard" for PNI treatment.
Fibroins/chemistry* ; Peripheral Nerve Injuries/therapy* ; Nerve Regeneration ; Tissue Scaffolds/chemistry* ; Humans ; Guided Tissue Regeneration/methods* ; Biocompatible Materials ; Animals ; Tissue Engineering/methods* ; Schwann Cells/cytology* ; Peripheral Nerves ; Neurons/cytology*

Charcot-Marie-Tooth disease (CMT) is the commonest form of inherited neuropathy and has an incidence of 1/2500. CMT1A is the commonest subtype of CMT, which is caused by duplication of peripheral myelin protein 22 (PMP22) gene and accounts for approximately 50% of CMT diagnosed by genetic testing. Duplication of PMP22 may influence the production of PMP22 mRNA and protein, and interfere with the proliferation, differentiation and apoptosis of Schwann cells. In addition, deregulation of NRG1/ErbB pathway and lipid metabolism can also lead to dysfunction of Schwann cells. Such factors may disturb the myelination process, leading to axon degeneration, muscle weakness, and atrophy subsequently. Accordingly, drug therapies for CMT1A are developed by targeting such factors. PXT3003, antisense oligonucleotides (ASOs) and small interfering RNA (siRNA) are supposed to down-regulate the level of PMP22 mRNA, while recombinant human NRG-1 (rhNRG1) and neurotrophin-3 (NT-3) may enhance Schwann cells survival and differentiation. In addition, lipid-supplemented diet may remedy the defect of lipid metabolism and maintain the proper structure of myelin. Other targeting drugs include ascorbic acid, progesterone antagonists, IFB-088, ADX71441, and ACE-083. This review is to sum up the pathogenesis of CMT1A and promising targeting drug therapies for further research.
Cell Differentiation ; Charcot-Marie-Tooth Disease ; genetics ; pathology ; therapy ; Genetic Testing ; Humans ; Schwann Cells ; cytology

OBJECTIVE: To investigate the mechanism of high glucose affecting the apoptosis of schwann cells through Nox4 NADPH oxidase. METHODS: The schwann cells of newborn Wistar rats were cultured in vitro. The cultured cells were divided into four groups: control group, high-glucose group, NOX4 siRNA group and control siRNA group (n=10). The WST-1 method was used to detect the cell vitality, and the DCFH-DA method was used to detect the contents of intracellular reactive oxygen free radicals (ROS). Nox4 and Caspase3 mRNA expressions were detected by real-time fluorescence quantitative RT-PCR. Nox4 and Caspase3 protein expressions were determined by Western blot. RESULTS: High glucose culture up-regulated Nox4 mRNA and protein expressions of schwann cells, decreased activity of schwann cells, increased intracellular ROS content, and promoted apoptosis by increasing Caspase3 mRNA and protein expressions. NOX4 siRNA blocked the accumulation of ROS in the high glucose cultured schwann cells, and reduced the damage of glucose on cell viability, by inhibiting NOX4 gene expression. NOX4 siRNA also reduced cell apoptosis by down-regulating Caspase3 mRNA and protein expressions. CONCLUSION Nox4 was involved in the hyperglycemic-induced apoptosis of schwann cells through ROS. The regulation of Nox4 expression or function might be a new way to treat diabetic peripheral neuropathy.
Animals ; Apoptosis ; Caspase 3 ; metabolism ; Cells, Cultured ; Culture Media ; Glucose ; NADPH Oxidase 4 ; metabolism ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Schwann Cells ; cytology ; metabolism

Objective To develop an improved method for culturing Schwann cells(SCs) by using both enzyme digestion and explants-culture approaches and compared with traditional explants-culture method and general hemi-explants-culture method. Methods Bilaterally sciatic nerves and brachial plexus nerves were dissected from 3 to 5-day-old neonatal SD rats and explants-culture method,general hemi-explants-culture method,and improved enzyme digestion combined with explants-culture method were adopted to culture SCs,respectively. SCs were digested and passaged after 7 days in culture and counted under the microscope. The purity of SCs was identified by S-100 immunofluorescence staining. Results The SCs of improved method group grew fastest and the total number of cells obtained was(1.85±0.13)×10(6);the SCs of the hemi-explants-culture method group grew slower than the improved method group and the total number of cells obtained was (1.10±0.10)×10(6);the SCs of the explants-culture method group grew slowest and the total number of cells obtained was (0.77±0.03)×10(6).The total number of cells obtained showed significant difference among the three groups(P<0.01). Immunofluorescence staining showed that the SCs purity was (95.73±1.51)% in the improved method group,(84.66±2.68)% in the hemi-explants-culture method group,and (74.50±4.23)% in the explants-culture method group(P<0.01). Conclusion The improved enzyme digestion combined with explants-culture method can obtain sufficient amount of high-purity SCs in a short time and thus may be applied in further research on peripheral nerve regeneration.
Animals ; Animals, Newborn ; Brachial Plexus ; cytology ; Cell Culture Techniques ; Cell Separation ; methods ; Cells, Cultured ; Enzymes ; Rats ; Rats, Sprague-Dawley ; Schwann Cells ; cytology ; Sciatic Nerve ; cytology

OBJECTIVETo determine the effect of AQP1 gene on facial nerve edema following injury through investigation of the relationship between the expression of AQP1 gene and Schwann cells swelling.

METHODSThe AQP1 expression in Schwann cells of mouse facial nerve tissues was detected by immunofluorescent staining. The transgenic protocol by lentivirus transduction was used to specifically upregulate AQP1 expression in Schwann cells. Lenti-AQP1 and CTRL (empty vector) transduced cells were observed during gene overexpression every 24 h for 6 days by using phase contrast microscopy. Cell volume of CTRL and Lenti-AQP1 treated cells was measured daily from the day of treatment, through day 6.

RESULTSSchwann cell primary cultures maintained a high level of AQP1 water channels, representing an ideal cell model to study the role of AQP1 in the facial nerve. The expression of AQP1 mRNA and protein in Schwann cells infected with the Lenti-AQP1 was increased significantly compared with CTRL lentivirus (P < 0.05). Lenti-AQP1 caused cell swelling in cultured Schwann cells, as validated by cell volume determinations (P < 0.01).

CONCLUSIONSAQP1 is an important factor responsible for the fast water transport of cultured Schwann cells. It plays an important role in facial nerve edema.

Animals ; Aquaporin 1 ; genetics ; metabolism ; Cell Size ; Edema ; etiology ; Facial Nerve ; metabolism ; Facial Nerve Diseases ; etiology ; Lentivirus ; Mice ; RNA, Messenger ; metabolism ; Schwann Cells ; cytology ; metabolism ; virology ; Time Factors ; Transduction, Genetic ; methods ; Up-Regulation

OBJECTIVETo investigate the effects of Pyrroloquinoline quinine (PQQ) on hydrogen peroxide-induced apoptosis of Schwann cells (SCs) and its mechanism.

METHODSSCs were isolated and cultured in vitro, and identified by S-100 immunofluorescence staining. The cultured SCs were divided into control group, hydrogen peroxide-treated group, hydrogen peroxide and PQQ treated groups. The intracellular superoxide dismutase (SOD) and malondialdehyde (MDA) content was detected; the apoptotic rate of SCs induced by hydrogen peroxide was determined by flow cytometry assay. The Hoechst33342 staining was used to detect the nuclear fragmentation and apoptotic nuclear condensation of SCs; the Rhodamine123 staining was used to detect the changes of mitochondrial membrane potential in SCs, the Western blot analysis was used to detect the expression of Bcl-2 in hydrogen peroxide induced SCs.

RESULTSThe SOD activity was significantly decreased and MDA level was increased in H2O2 induced SCs (P < 0.05), after addition of PQQ, the SOD content increased and MDA content decreased (P < 0.05). Flow cytometry results showed that the early apoptotic rate was 58.8% in H2O2 induced SCs, which has significant difference compared with the control group (P < 0.05), after addition of 10, 50, 100 nmol/L PQQ, the apoptotic rates were reduced to 33.7%, 18.7%, 3.9% respectively, showing significantly different with injured group (P < 0.05). Hoechst 33342 staining showed that H2O2 induced SCs had typical morphological characteristics, such as uptake of nuclear chromatin, nuclear shrinkage, nuclear fragmentation phenomenon. The proportion of apoptotic cells after PQQ treatment reduced. Rhodamine staining results showed that the H2O2 induced mitochondrial membrane potential reduction in SCs, which was reversed by addition of PQQ. Western blot analysis showed that the expression of Bcl-2 was decreased in H2O2 induced SCs, while it increased significantly after addition of PQQ (P < 0.05).

CONCLUSIONPQQ has a protective effect on oxidative stress-induced apoptosis of SCs.

Apoptosis ; drug effects ; Benzimidazoles ; Cell Nucleus ; drug effects ; DNA Fragmentation ; Fluorescent Dyes ; Humans ; Hydrogen Peroxide ; pharmacology ; Malondialdehyde ; metabolism ; Oxidants ; pharmacology ; Oxidative Stress ; Pyrroles ; pharmacology ; Quinine ; pharmacology ; Quinolines ; pharmacology ; Schwann Cells ; cytology ; drug effects ; Superoxide Dismutase ; metabolism

BACKGROUNDVarious tissue engineering strategies have been developed to facilitate axonal regeneration after spinal cord injury. This study aimed to investigate whether neural stem cells (NSCs) could survive in poly(L-lactic-co-glycolic acid) (PLGA) scaffolds and, when cografted with Schwann cells (SCs), could be induced to differentiate towards neurons which form synaptic connection and eventually facilitate axonal regeneration and myelination and motor function.

METHODSNSCs and SCs which were seeded within the directional PLGA scaffolds were implanted in hemisected adult rat spinal cord. Control rats were similarly injured and implanted of scaffolds with or without NSCs. Survival, migration, differentiation, synaptic formation of NSCs, axonal regeneration and myelination and motor function were analyzed. Student's t test was used to determine differences in surviving percentage of NSCs. One-way analysis of variance (ANOVA) was used to determine the differences in the number of axons myelinated in the scaffolds, the mean latency and amplitude of cortical motor evoked potentials (CMEPs) and Basso, Beattie & Bresnahan locomotor rating scale (BBB) score. The χ(2) test was used to determine the differences in recovery percentage of CMEPs.

RESULTSNSCs survived, but the majority migrated into adjacent host cord and died mostly. Survival rate of NSCs with SCs was higher than that of NSCs without SCs ((1.7831 ± 0.0402)% vs. (1.4911 ± 0.0313)%, P < 0.001). Cografted with SCs, NSCs were induced to differentiate towards neurons and might form synaptic connection. The mean number of myelinated axons in PLGA + NSCs + SCs group was more than that in PLGA + NSCs group and in PLGA group ((110.25 ± 30.46) vs. (18.25 ± 3.30) and (11.25 ± 5.54), P < 0.01). The percentage of CMEPs recovery in PLGA + NSCs + SCs group was higher than in the other groups (84.8% vs. 50.0% and 37.5%, P < 0.05). The amplitude of CMEPs in PLGA + NSCs + SCs group was higher than in the other groups ((1452.63 ± 331.70) µV vs. (428.84 ± 193.01) µV and (117.33 ± 14.40) µV, P < 0.05). Ipsilateral retransection resulted in disappearance again and functional loss of CMEPs for a few days. But contralateral retransection completely damaged the bilateral motor function.

CONCLUSIONSNSCs can survive in PLGA scaffolds, and SCs promote NSCs to survive and differentiate towards neurons in vivo which even might form synaptic connection. The scaffolds seeded with cells facilitate axonal regeneration and myelination and motor function recovery. But regenerating axons have limited contribution to motor function recovery.

Animals ; Axons ; physiology ; Cells, Cultured ; Electrophysiology ; Female ; Fluorescent Antibody Technique ; Lactic Acid ; chemistry ; Nerve Regeneration ; physiology ; Neural Stem Cells ; cytology ; Polyglycolic Acid ; chemistry ; Pregnancy ; Rats ; Rats, Wistar ; Schwann Cells ; cytology ; Spinal Cord Injuries ; therapy ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

OBJECTIVETo evaluate the effect of serum containing Jinmaitong Capsule (JMT) on apoptosis of Schwann cells (SCs) that are cultured in high glucose at the cellular and molecular levels.

METHODSSCs were cultured in Dulbecco's modified Eagle's medium (control group), high glucose (50 mmol/L) medium supplemented with 20% rat serum (HG group), and 50 mmol/L glucose medium supplemented with serum containing JMT (JMT group). SC apoptosis was detected using a terminal deoxynucleotidyl transferase dUTP nick end labeling kit. The expression of Bcl-2 and the caspase-3 p20 subunit in SCs were detected by realtime fluorogenic quantitative polymerase chain reaction and confocal laser scanning microscopy, respectively.

RESULTSNo apoptosis was detected in SCs that were cultured in the control group. The percentage of apoptosis of SCs cultured in the HG group was much higher than that in the control group. The apoptosis of SCs in the JMT group was lower than that in the HG group. Fluorescence intensity of Bcl-2 and the expression of Bcl-2 mRNA in SCs that were cultured in the HG group were much lower than those in the control group and much higher than those in the JMT group (P<0.01). The fluorescence intensity of caspase-3 p20 and the expression of caspase-3 p20 mRNA in SCs that were cultured in the HG group were much higher than those in the control group (P<0.01), and they were remarkably lower in the JMT group (P<0.01).

CONCLUSIONSJMT effectively prevents SC apoptosis that is induced by high glucose. This effect may be because of increased expression of Bcl-2 mRNA and protein and decreased expression of caspase-3 p20 mRNA and protein.

Animals ; Apoptosis ; drug effects ; Capsules ; Caspase 3 ; genetics ; metabolism ; Cell Proliferation ; drug effects ; Cell Shape ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Regulation ; drug effects ; Glucose ; pharmacology ; Male ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; S100 Proteins ; metabolism ; Schwann Cells ; cytology ; drug effects ; enzymology ; Serum ; metabolism

Olfactory ensheathing cells (OECs) are a unique type of glia with common properties of astrocyte and Schwann cells. Cultured OECs have two morphological phenotypes, astrocyte-like OECs and Schwann cell-like OECs. Reversible changes have been found between these two morphological phenotypes. However, the molecular mechanism underlying the regulation of these reversible changes is still unknown. The aim of this paper is to establish a method for the morphology plasticity of cultured OECs, and investigate the underlying mechanism. Using the primary culture of OECs and immunocytochemistry, the morphology of OECs was observed under serum, serum free media or dB-cAMP drug treatment. Statistical analysis was performed to test differences among the percentages of OEC subtypes under these conditions. The results showed that under serum free media, (95.2±3.7)% of OECs showed Schwann cell-like morphology, and (4.8±3.7)% of OECs showed astrocyte-like morphology; however, under 10% serum media, (42.5±10.4)% of OECs exhibited Schwann cell-like morphology, and (57.5±10.4)% of OECs exhibited astrocyte-like morphology. When media was changed back to serum free media for 24 h, (94.8±5.0)% of OECs showed Schwann cell-like morphology, and (5.2±5.0)% of OECs showed astrocyte-like morphology. Furthermore, culture condition with or without serum did not affect the expression of OEC cell marker, p-75 and S-100. Finally, dB-cAMP, an analog of cAMP, through inhibiting the formation of F-actin stress fibers and focal adhesion, induced the morphology switch from astrocyte-like to Schwann cell-like morphology under serum condition, promoted the branches and the growth of processes. These results suggest that serum induces the morphology plasticity of cultured OECs, which is mediated by cytoplasmic cAMP level through regulating the formation of F-actin stress fibers and focal adhesion.
Animals ; Astrocytes ; cytology ; physiology ; Cells, Cultured ; Culture Media ; pharmacology ; Cyclic AMP ; physiology ; Male ; Neuroglia ; cytology ; physiology ; Olfactory Bulb ; cytology ; physiology ; Rats ; Rats, Sprague-Dawley ; Schwann Cells ; cytology ; physiology ; Serum ; physiology

OBJECTIVETo investigate the phenotypic, molecular and biological characteristics of adipose tissue-derived stromal cells (ADSCs) differentiated alonely a Schwann cells (SCs) lineage and to provide a new cells' seed source for nerve tissue engineering or cell therapy.

METHODSCultured ADSCs were isolated from SD rats and the undifferentiated ADSCs were confirmed by detection of MSC-specific cell-surface markers. The ADSCs were differentiated along a glial cell lineage using an established cocktail of growth factors. Following differention, we used immunofluorescene staining and RT-PCR to evaluate the characteristics of differentiated WJMSCs.

RESULTSADSCs were successfully isolated from the rats' fat tissue. The isolated ADSCs expressed CD29, CD90 but not CD34, CD44 nor CD45. Osteogenic differentiation was detected by Alizarin red staining and adipogenic differentiation was comfirmed by Oil-red O staining. ADSCs treated with a mixture of glial growth factors adopted a spindle-like morphology similar to Schwann cells. Immunocytochemical staining and RT-PCR analysis revealed that the treated cells expressed the glial markers S100, P75 and glial fibrillary acidic protein indicative of differentiation.

CONCLUSIONADSCs can be differentiated into cells that are Schwann-like in terms of morphologic features and phenotype and could be suitable Schwann-cell substitutes for nerve repair in clinical applications.

Adipose Tissue ; cytology ; Animals ; Cell Differentiation ; physiology ; Cells, Cultured ; Male ; Mesenchymal Stromal Cells ; cytology ; Rats ; Rats, Sprague-Dawley ; Schwann Cells ; cytology