Research and application of carbon nanomaterials in peripheral nerve regeneration / 中国组织工程研究

BACKGROUND:Although nerve conduits provide an effective treatment approach for nerve repair,traditional nerve conduits merely serve as mechanical channels in the repair process.The therapeutic effect still needs to be improved.Carbon nanomaterials have good physicochemical properties and hold great potential in fields such as electrochemistry and tissue engineering.Nerve conduits loaded with carbon nanomaterials,after appropriate functional modifications,are expected to further enhance the quality of nerve repair. OBJECTIVE:To review the recent research progress of carbon nanomaterial-loaded nerve conduits/scaffolds for peripheral nerve repair. METHODS:PubMed,Web of Science,China National Knowledge Infrastructure(CNKI),and Wanfang databases were searched for the literature on the application of carbon nanomaterial catheters in peripheral nerve regeneration.English keywords were"carbon nanomaterials,carbon-based nanomaterials,nerve conduit,nerve guidance conduit,scaffold,nerve regeneration,peripheral nerve repair,peripheral nerve injury"and Chinese keywords were"carbon nanomaterials,carbon materials,graphene,carbon nanotubes,nerve conduits,nerve scaffolds,nerve repair,nerve regeneration,peripheral nerve injury".Finally,69 articles were selected for this review. RESULTS AND CONCLUSION:(1)Carbon nanomaterials primarily restore damaged neural bioelectric signal conduction by activating calcium ion channels and inducing intracellular calcium activity.The application of various nerve conduit design strategies has improved the effectiveness of nerve repair.(2)Successful intraneural vascularization is the prerequisite for repairing peripheral nerve injuries.Reactive oxygen species and reactive nitrogen species generated by carbon nanomaterials trigger subsequent signaling pathways that promote intraneural vascularization.(3)The ratio of M1 to M2 macrophages affects the repair of peripheral nerve injuries.Carbon nanomaterials promote the polarization of macrophages into the M2 phenotype,thereby exerting their anti-inflammatory and regenerative effects.(4)Some carbon nanomaterials may induce excessive generation of reactive oxygen species intracellularly,potentially exhibiting cytotoxicity detrimental to nerve repair.However,appropriate functional modifications can improve the adverse effects caused by carbon nanomaterials.(5)Although carbon nanomaterials can restore the microenvironment of peripheral nerve injuries and play a positive role in promoting peripheral nerve regeneration,their inherent cytotoxicity and unclear in vivo degradation pathways still pose challenges for clinical application.However,by employing methods such as functional modification,it is possible to enhance the biocompatibility of carbon nanomaterials.Modified carbon nanomaterials have promising prospects in the field of neural tissue engineering.

Application of corneal neutrotization in the treatment of neurotrophic keratopathy / 中华实验眼科杂志

Neurotrophic keratopathy (NK) is a degenerative disease in which damage to the corneal nerves leads to corneal hypoesthesia and even blindness.Traditional NK treatments aim at supporting corneal healing and preventing progression of corneal damage.In recent years, corneal neurotization has made some progress in NK.Compared with traditional treatment, it can not only solve the problem of corneal nerve defect, and avoid the subsequent keratopathy, but also significantly restore corneal sensitivity, corneal epithelium and vision.Corneal neurotization surgery methods are mainly divided into direct corneal neurotization (DCN) and inderect corneal neurotization (ICN).At present, this surgical method has gradually been used clinically, and has achieved satisfactory effects on unilateral NK caused by herpes virus and neuroma, as well as bilateral NK.However, it is little known about the surgical treatment of NK caused by dry eye, diabetes, and chronic glaucoma.In the future, multi-center prospective randomized studies can be conducted to further improve the treatment of NK with other causes.This article introduces this new surgical technique from three aspects, the specific surgical procedures of corneal neurotization, the selection of surgical methods, and the timing of the operation.

Interaction between Schwann cells and macrophages during regeneration process after peripheral nerve injury / 中华显微外科杂志

As the important components of peripheral nerve tissue, Schwann cells and macrophages interact with each other throughout the whole process of nerve regeneration. They play a key role in Wallerian degeneration, myelin clearance, axonal regeneration and target organ reinnervation in promotion of the repair of a peripheral nerve. In order to improve the simple strategy in treatment of peripheral nerve injury (PNI), great attention about the significance interaction mechanism between Schwann cells and macrophages in the process of nerve regeneration should be paid, as well as the continuous improvement in researches on the repair mechanism of a PNI. Trauma Centre, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine summarises the interaction mechanism of Schwann cells and macrophages in the regeneration of PNI through literature reviews, from 2015 to 2023, on the mechanisms of Schwann cells and macrophages in PNI repair, hence to draw new ideas in the research and clinical treatment of PNI.

The Hoffmann-Tinel Sign: Historical Background and Clinical Significance / Sinal de Hoffmann-Tinel: Contexto histórico e significado clínico

The Hoffmann-Tinel sign is well-known to professionals dealing with nerve lesions and is widely used as a provocative test. It was described by Paul Hoffman and Jules Tinel in the same year (1915), independently. In the present article, a biographical sketch of both authors is presented and the method for eliciting the sign and the sometimes controversial information of its results are discussed.

O sinal de Hoffmann-Tinel é bem conhecido pelos profissionais que lidam com lesões de nervos, sendo amplamente utilizado como um teste provocativo. Foi descrito por Paul Hoffmann e por Jules Tinel no mesmo ano (1915), de forma independente. No presente artigo, é apresentado um esboço biográfico de ambos autores e são discutidas a forma de obter o sinal e as informações, por vezes controversas, fornecidas por seus resultados.

End-to-side neurorrhaphy in the reconstruction of peripheral segmental neural loss: an experimental study

Purpose: To evaluate the effects on peripheral neural regeneration of the end-to-side embracing repair technique compared to the autograft repair technique in Wistar rats. Methods: Fifteen male Wistar rats were divided into three groups with five animals each: denervated group (GD), autograft group (GA), and embracing group (EG). For the evaluation, the grasping test, electroneuromyography (ENMG), and muscle weight assessment were used. Results: Muscle weight assessment and ENMG did not show significant neural regeneration at the end of 12 weeks in the DG and GE groups, but only in GA. The grasping test showed an increase in strength between the surgery and the fourth week in all groups, and only the GA maintained this trend until the 12th week. Conclusions: The present study indicates that the neural regeneration observed in the end-to-side embracing neurorrhaphy technique, in the repair of segmental neural loss, is inferior to autograft repair in Wistar rats.

Investigation of the Neuro-Regenerative Effects of Bioresonance and Magnetotherapy in Sciatic Nerve Damage-Induced Rats / Investigación de los Efectos Neurorregenerativos de Biorresonancia y Magnetoterapia en Ratas Inducidas por Daño del Nervio Ciático

SUMMARY: Peripheral nerve damage is a significant clinical problem that can lead to severe complications in patients. Regarding the regeneration of peripheral nerves, it is crucial to use experimental animals' nerves and use different evaluation methods. Epineural or perineural suturing is the gold standard in treating sciatic nerve injury, but nerve repair is often unsuccessful. This study aimed to investigate the neuroregenerative effects of magnetotherapy and bioresonance in experimental animals with sciatic nerve damage. In this study, 24 female Wistar rats were divided into 7 groups (n=6) as follows: Group 1 (Control), Group 2 (Axonotmesis control), Group 3 (Anastomosis control), Group 4 (Axonotmesis + magnetotherapy), Group 5 (Anastomosis + magnetotherapy), Group 6 (Axonotmesis + bioresonance), Group 7 (Anastomosis + bioresonance). Magnetotherapy and bioresonance treatments were applied for 12 weeks. Behavioural tests and EMG tests were performed at the end of the 12th week. Then the rats were sacrificed, and a histopathological evaluation was made. The statistical significance level was taken as 5 % in the calculations, and the SPSS (IBM SPSS for Windows, ver.21) statistical package program was used for the calculations. Statistically significant results were obtained in animal behaviour tests, EMG, and pathology groups treated with magnetotherapy. There was no statistically significant difference in the groups treated with bioresonance treatment compared to the control groups. Muscle activity and nerve repair occurred in experimental animals with acute peripheral nerve damage due to 12 weeks of magnetotherapy, and further studies should support these results.

El daño a los nervios periféricos es un problema clínico importante que puede conducir a complicaciones graves en los pacientes. En cuanto a la regeneración de los nervios periféricos, es crucial utilizar los nervios de los animales de experimentación y diferentes métodos de evaluación. La sutura epineural o perineural es el gold estándar en el tratamiento de lesiones del nervio ciático, pero la reparación del nervio a menudo no tiene éxito. Este estudio tuvo como objetivo investigar los efectos neuroregenerativos de la magnetoterapia y la biorresonancia en animales de experimentación con daño del nervio ciático. En el estudio, 24 ratas hembras Wistar se dividieron en 7 grupos (n=6) de la siguiente manera: Grupo 1 (Control), Grupo 2 (Control de axonotmesis), Grupo 3 (Control de anastomosis), Grupo 4 (Axonotmesis + magnetoterapia), Grupo 5 (Anastomosis + magnetoterapia), Grupo 6 (Axonotmesis + biorresonancia), Grupo 7 (Anastomosis + biorresonancia). Se aplicaron durante 12 semanas tratamientos de magnetoterapia y biorresonancia. Las pruebas de comportamiento y las pruebas de EMG se realizaron al final de la semana 12. Luego se sacrificaron las ratas y se realizó una evaluación histopatológica. El nivel de significación estadística se tomó como 5 % en los cálculos, y se utilizó el programa de paquete estadístico SPSS (IBM SPSS para Windows, ver.21). Se obtuvieron resultados estadísticamente significativos en pruebas de comportamiento animal, EMG y grupos de patología tratados con magnetoterapia. No hubo diferencia estadísticamente significativa en los grupos con tratamiento de biorresonancia en comparación con los grupos controles. La actividad muscular y la reparación nerviosa, se produjeron en animales de experimentación con daño nervioso periférico agudo, debido a 12 semanas de magnetoterapia.Estudios adicionales deberían respaldar estos resultados.

The effects of fat graft and platelet-rich fibrin combination after epineurectomy in rats

SUMMARY OBJECTIVE: One of the most important factors that adversely affects the outcome of peripheral nerve surgery is the formation of epineural and extraneural scar tissue after surgery. Many surgical methods and pharmacological and chemical agents have been used to prevent the formation of epineural scar tissue, but satisfactory results have not been achieved in clinical applications. The purpose of this study was to investigate the combined effect of fat graft and platelet-rich fibrin on the formation of epineural scar tissue and on nerve healing in the mature rat model. METHODS: A total of 24 female Sprague-Dawley rats were used. A circumferential segment of epineurium was excised from both bilateral sciatic nerves. The epineurectomized right nerve segment was wrapped with a combination of fat graft and platelet-rich fibrin (experimental group), while the left nerve segment did not receive any surgical procedure other than the epineurectomy (sham group). Notably, 12 randomly selected rats were sacrificed in the fourth week for histopathological examination of early results. The other 12 rats were sacrificed in the eighth week for late results. RESULTS: The formation of fibrosis, inflammation, and myelin degeneration were less common in the experimental group, while nerve regeneration was found to be higher at both 4 and 8 weeks. CONCLUSION: The intraoperative application of a combination of fat graft and platelet-rich fibrin appears to be effective on nerve healing after surgery at both the early and late periods.

Advances in the raw material selection and functional design of artificial nerve guidance conduits / 生物工程学报

Artificial nerve guidance conduits (NGCs) are synthetic nerve grafts that are capable of providing the structural and nutritional support for nerve regeneration. The ideal NGCs have plenty of requirements on biocompatibility, mechanical strength, topological structure, and conductivity. Therefore, it is necessary to continuously improve the design of NGCs and establish a better therapeutic strategy for peripheral nerve injury in order to meet clinical needs. Although current NGCs have made certain process in the treatment of peripheral nerve injury, their nerve regeneration and functional outcomes on repairing long-distance nerve injury remain unsatisfactory. Herein, we review the nerve conduit design from four aspects, namely raw material selection, structural design, therapeutic factor loading and self-powered component integration. Moreover, we summarize the research progress of NGCs in the treatment of peripheral nerve injury, in order to facilitate the iterative updating and clinical transformation of NGCs.

Research on the reuse of mismatched regenerated motor axons of brachial plexus and the effect of target organs on regeneration in rats / 中华显微外科杂志

Objective:To confirm the reuse of mismatched regenerated motor axons of brachial plexus and explore the effect of target organs on their regeneration in a rat model.Methods:This study was carried out between January 2021 and December 2021 at the research laboratory of the Department of Microsurgery, Orthopaedic Trauma and Hand Surgery, the First Affiliated Hospital of Sun Yat-sen University. Animals were randomly assigned into 2 groups, as a regeneration group (RGen) with 5 subgroups and a reuse group (RUs) with 3 subgroups. There were 6 rats per subgroup with 42 rats in total. It was observed that in the groups of RGen1-4, after the transection and suture of the musculocutaneous nerve, the motor axons of the proximal end could accurately grow into the distal corresponding endoneural tube. It was also observed that in the mismatched regenerated group, motor axons were the axons that grew into the endoneurial tube of the lateral forearm cutaneous nerve (LFCN), and other non-target organ contacts were made to the regenerated nerves after mismatch. It was specifically further divided into RGen1, the group without an organ for nerve to make contact with; RGen2, the group with skin as the target organ with nerves contact by neurorrhaphy; RGen3, the group with skin as the target organ with originally reserved natural nerve contact; RGen4, the group with muscle as the target organ with nerves contact by neurorrhaphy and RGen5, a control group. After 8 weeks, the positive area (PA), mean density (MD) and integral optical density (IOD) were measured, with AChE and ChAT fluorescence staining of the medial branch of LFCN, to evaluate the regenerated nerves after mismatch. Of the RUs group, firstly, the innervating branches of the flexor carpi radialis (FCR) were dissected and exposed, then further assigned according to initially innervated FCR (RUs1), contacted with regenerated nerves after mismatch (RUs2) and denervated (RUs3), respectively. After 8 weeks, compound muscle action potential (CMAP) and wet weight ratio of FCR were taken. Masson staining of FCR was also performed to evaluate muscle reinnervation by the regenerated nerves after mismatch. Data analysis with One-Way ANOVA and Bonferroni 0.05 indicated a statistically significant difference.Results:In the RGen groups, after AChE staining, the PA, MD and IOD of RGen3 and RGen4 were higher than that of RGen1 and RGen5, and PA of RGen4 were higher than that of RGen2, with a statistically significant difference ( P<0.05). After ChAT staining, the values of PA and IOD of RGen3 and RGen4 were higher than that of RGen1 and RGen5, and PA of RGen4 were higher than that of RGen2, with a statistically significant difference ( P<0.05). In the RUs, electrophysiological assessment showed that no CMAP was observed in RUs3, there was no significant difference in Latency of RUs1 and RUs2. The difference was statistically significant ( P<0.05). Wet weight rate of muscle of RUs1 (98.91%±3.86%) was higher than that of RUs3 (86.67%±4.68%) with a statistically significant difference ( P<0.01), but no significant difference when compared with RU2 (92.74%±3.88%). Masson staining showed that the CVF value of RUs2 (8.61%±1.16%) was significantly higher than that of RUs1 (3.17%±0.76%), and statistic significantly lower than that of RUs3 (16.44%±2.26%)( P<0.01). Conclusion:Target organ contact can promote the regenerated nerves after mismatched regeneration, and the muscle target organs exhibit greater facilitation than the cutaneous target organs. Besides, regenerated nerves after mismatch can establish effective innervation with muscle target organs, comfirming their effective reuse.

An enriched environment can promote nerve regeneration in a mouse model of sciatic nerve compression / 中华物理医学与康复杂志

Objective:To document any effect of environmental enrichment on nerve regeneration in a mouse model of sciatic nerve compression and explore its mechanism.Methods:A crushed sciatic nerve model was successfully established in 22 C57BL/6 mice, and they were then randomly divided into an intervention group and a control group. The mice of the intervention group were raised in a cage with an enriched environment, while those of the control group were kept in a standard cage. Two weeks later, both groups′ gait was analyzed and the compound muscle action potential (CMAP) of the sciatic nerve was measured. The proportion of myelinated sciatic nerve fibers was examined using toluidine blue staining, and the expression of myelin basic protein (MBP), growth associated protein-43 (GAP43) and p75 neurotrophin receptor (p75 NTR) was measured using immunofluorescence intensity. Results:①The latency of the CMAP [(1.05±0.04)ms] was significantly shortened in the intervention group compared with the control group and the amplitude was significantly higher. ②Gait analysis showed a significant increase in the average contact intensity, stride length and stride rate of the intervention group compared with the control group. However, the step axis angle of the intervention group was significantly smaller than in the control group on average. ③The stained nerve fibers in the intervention group were orderly and dense, and the average number of myelinated fibers was significantly greater than in the control group. ④Quantitative analysis of the immunofluorescence showed that the levels of MBP, GAP43 and p75 NTR in the sciatic nerves of the intervention group were, on average, significantly higher than in the control group. Conclusion:An enriched environmental can promote the regeneration and functional recovery of crushed sciatic nerves by promoting the proliferation and myelination of Schwann cells.

Sciatic nerve derived exosomes in promotion of axon regeneration and functional recovery following peripheral nerve injury in rat / 中华显微外科杂志

Objective:To explore the effect of sciatic nerve derived exosomes(SN-EXO) on axon regeneration and functional recovery after peripheral nerve injury(PNI).Methods:From March 2021 to October 2022, the Department of Orthopedics of the First Affiliated Hospital of Zhengzhou University studied the effect of SN-EXO on the proliferation of Schwann cells(SCs) through EdU cell proliferation experiment. Twenty-one healthy male SD rats were randomly divided into 3 groups of sham operation, peripheral nerve injury(PNI) and SN-EXO treatment, with 7 rats in each group. The right sciatic nerves of rat models in sham group were exposed without injury. In the rat in PNI group and SN-EXO treatment group, PBS and SN-EXO were injected under the epineurium of right sciatic nerves following sciatic nerve crush. Sciatic nerve function index(SFI) was performed at 28 days after operation, and then sacrificed. Right sciatic nerves were removed for further exploration of nerve regeneration. The histopathological changes and axon arrangement of sciatic nerves were evaluated by HE staining. Regeneration efficiency of neurofilaments and SCs were obserred by NF200 and S100β double staining of sciatic nerve. The data obtained were statistically analyzed, and P<0.05 was statistically significant. Results:It was found that SN-EXO can significantly enhance the proliferation ability of SCs, with statistically significant difference( P<0.05). SFI in SN-EXO treatment group and PNI group were(-27.65±4.36) and(-57.33±7.49), respectively, and the difference was statistically significant( P<0.05). Axons in SN-EXO treatment group were arranged more closely and orderly than those in the PNI group at 28 days after operation, and there were less injury induced axon disintegration and vacuolation. Immunofluorescence assay indicated that NF200 and S100β fluorescence intensity in SN-EXO treatment group was significantly higher than that in the PNI group, and the difference was statistically significant( P<0.05). Conclusion:SN-EXO could enhance the proliferation of SCs to promote axon regeneration following peripheral nerve injury.

Expression pattern of MMP-12 in long-term optic nerve regeneration induced by lens injury / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To investigate the expression changes of MMP-12 during the long-term axon regeneration induced by the lens injury after the optic nerve clamp trauma in sprague-dawley(SD)rats.METHODS: The optic nerve injury model and lens injury model of SD rats were established, and the 24 experimental animals were divided into control group; lens injury group; optic nerve injury group; lens injury combined with optic nerve injury group, with 6 rats in each group. Reference transcriptome sequencing was used to analyze the expression changes of differentially expressed genes in the injured optic nerve region, and relevant differentially expressed genes with high expression were screened. Quantitative real-time polymerase chain reaction(qRT-PCR)and enzyme-linked immunosorbent assay(ELISA)were used to quantify the expression changes of matrix metalloproteinase-12(MMP-12)in the injured optic nerve region.RESULTS: The Principal Component Analysis of transcriptome sequencing indicated that lens injury combined with optic nerve injury was the principal component of gene expression change. Analysis of gene expression differences showed that the expression of MMP-12 gene was up-regulated in the lens injury combined with optic nerve injury group. The mRNA expression level of MMP-12 in the lens injury combined optic nerve injury group was up-regulated compared with the control group, the optic nerve injury group and the lens injury group at 14d and 21d after successful modeling(P<0.05). At 7, 28d, there was no difference in expression among all groups. The protein expression level of MMP-12 in the lens injury combined with optic nerve injury group was up-regulated compared with the control group and optic nerve injury group at 7, 14 and 21d after successful modeling(P<0.05), and it was up-regulated in the lens injury group combined with optic nerve injury group compared with optic nerve injury group at 21d(P<0.05). At 28d, there was no difference in expression among all groups.CONCLUSION: The up-regulated expression of MMP-12 may be involved in the long-term regeneration of the optic nerve after lens injury.

Nerve repair effect of olanzapine-mediated cyclic AMP response element binding protein/brain-derived neurotrophic factor/receptor tyrosine kinase receptors B pathway on schizophrenic rats / 解剖学报

Objective To stud)' the nerve repair effect of olanzapine on schizophrenia model rats through its effect on cyclic AMP response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF)/receptor tyrosine kinase receptors B (TrkB) pathway. Methods Total 60 rats were divided into control group, model group, olanzapine low, middle and high dose group. The rats in the model group, olanzapine low, middle and high dose groups were injected intraperitoneally with MK-801[0. 2 mg/(kg-d) ], while the control injected with the same amount of normal saline. The low, middle and high dose olanzapine groups were perfused with olanzapine solution of 0. 5 mg/(kg-d),1. 0 mg/(kg-d) and 1. 5 mg/(kg-d) respectively. The behavior of rats was scored according to ataxia and stereotyped behavior standards, cognitive function and learning ability were evaluated by Moms water maze test, serum tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6) levels were detected by ELISA method, hippocampal histopathology was observed under microscope, and apoptosis and expression of CREB/BDNF/TrkB pathway related proteins in hippocampus were detected. Results Compared with the control group, the ataxia, the score of stereotyped behavior, the expression of TNF-a, IL-6 and the rate of apoptosis in the model group increased significantly (P < 0 . 01). Compared with the control group, the number of crossing the platform, the time of staying in the target quadrant and the relative expression of CREB, p-CREB, p-TrkB, TrkB and BDNF protein in the model group decreased significantly (P<0. 01), and those in the low and middle dose olanzapine groups decreased significantly (P < 0 . 05). Compared with the model group, the times of crossing the platform and the stay time in the target quadrant increased significantly in the low and middle dose olanzapine groups (P< 0. 05). In the model group and the low dose olanzapine group, the hippocampal cells were swollen obviously, the nucleus was broken and divided, pyknosis, and the tissue aiTangement was disorderly, while the phenomenon of fragmentation and nuclear pyknosis was rarely seen in the middle and high dose olanzapine groups. Conclusion The nerve repair mechanism of olanzapine on schizophrenic model rats is related to improving cognitive impainnent, protecting hippocampal neurons and activating the expression of CREB/BDNF/TrkB signal pathway in rats.

Effects of activating mTORC2/Akt signaling pathway on dopaminergic neurons and behaviors in 6-hydroxydopamin model mice / 解剖学报

Objective To explore the effect of activation of mammalian target of rapmycin complex 2(mTORC2)/Akt signaling pathway on dopaminergic neurons and behavior in 6-hydroxydopamine (6-OHDA) model mice and its possible mechanism. Methods Selecting 36 mice which The Nestin-CreERTM and ROSA26-LacZ reporter genes were detected at the same time in 3-month-old male C57BL/6J mice weighing 20-25 g divideng them into 4 gruops, NS+ corn oil group, 6-OHDA+corn oil group, 6-OHDA+PP242 group and 6-OHDA+A-443654 group, and 6-OHDA was injected into the right striatum of the brain to replicate the Parkinson’s disease (PD) model of mice, and then daily intraperitoneal injection of mTORC2/Akt signaling pathway agonist A-443654 or inhibitor PP242. Serum interleukin-1β (IL-1β) and tumor necrosis factor-α(TNF-α)levels were measured by enzyme-linked immunosorbent assay. Immunohistochemistry and immunofluorescence staining were performed to investigate the change of microglia, dopaminergic neurons as well as neural progenitor cells (NPCs). Western blotting was used to detect the expression of related protein of mTORC2/Akt signaling pathway including rictor, p-Akt and regulated in development and DNA dgmage responses 1(REDD1) and the interaction between them were verified by immunoprecipitation. Finally, the behavioral performance of each group of mice was observed. Results With the activation of microglia and the increase of inflammatory factors in PD model mice, the number of dopaminergic neurons in the substantia nigra(SN) decreased significantly, and the motor function of the mice was impaired, but the number of NPCs increased significantly compared with the control mice, mTORC2/Akt signaling pathway related protein expression was also significantly up-regulated. A-443654 treatment further up-regulated the expression of these proteins, meanwhile the indicators mentioned above were ameliorated. However, the inhibitor PP242 treatment group showed completely opposite result with the agonist group. Conclusion A-443654 can promote the proliferation of NPCs and the number of new-born dopaminergic neurons by up-regulating related proteins of mTORC2/Akt signaling pathway, and reducing the activation of microglia and the level of inflammation factors, which ultimately lead to the amelioration of SN-striatal dopaminergic neurons and behavioral performance in PD model mice.

Human Platelet-Rich Plasma-Derived Exosomes Promote the Proliferation of Schwann Cells Cultured in Vitro / 中国医学科学院学报

Objective To investigate the effect of human platelet-rich plasma-derived exosomes(PRP-exos)on the proliferation of Schwann cell(SC)cultured in vitro. Methods PRP-exos were extracted by polymerization-precipitation combined with ultracentrifugation.The morphology of PRP-exos was observed by transmission electron microscopy,and the concentration and particle size distribution of PRP-exos were determined by nanoparticle tracking analysis.Western blotting was employed to determine the expression of the marker proteins CD63,CD81,and CD9 on exosome surface and the platelet membrane glycoprotein CD41.The SCs of rats were isolated and cultured,and the expression of the SC marker S100β was detected by immunofluorescence staining.The fluorescently labeled PRP-exos were co-cultured with SCs in vitro for observation of their interaction.EdU assay was employed to detect the effect of PRP-exos on SC proliferation,and CCK-8 assay to detect the effects of PRP-exos at different concentrations(0,10,20,40,80,and 160 μg/ml)on SC proliferation. Results The extracted PRP-exos appeared as uniform saucer-shaped vesicles with the average particle size of(122.8±38.7)nm and the concentration of 3.5×1012 particles/ml.CD63,CD81,CD9,and CD41 were highly expressed on PRP-exos surface(P<0.001,P=0.025,P=0.004,and P=0.032).The isolated SCs expressed S100β,and PRP-exos could be taken up by SCs.PRP-exos of 40,80,and 160 μg/ml promoted the proliferation of SCs,and that of 40 μg/ml showed the best performance(all P<0.01). Conclusions High concentrations of PRP-exos can be extracted from PRP.PRP-exos can be taken up by SCs and promote the proliferation of SCs cultured in vitro.

The efficacy of corticosteroid after facial nerve neurorrhaphy: a systematic review and meta-analysis of randomized controlled trial

Abstract Objectives: The benefit of corticosteroids following facial nerve neurorrhaphy in the setting of complete transection is questionable. This systematic review and meta-analysis aimed to evaluate corticosteroid efficacy on facial nerve regeneration and functional recovery after complete disruption and neurorrhaphy. Methods: Randomized controlled trials on both human and animal models from Ovid MEDLINE and Ovid EMBASE studying corticosteroid efficacy in complete facial nerve disruption followed by neurorrhaphy were included. Data were extracted and pooled for meta-analysis. The outcomes were evaluated from electrophysiology, histology, and functional recovery. However, no randomized controlled trial in human was performed. Possibly, performing human trials with histopathology may not be feasible in clinical setting. Results: Six animal studies (248 participants) met inclusion criteria. Electrophysiologic outcomes revealed no differences in latency (Standardized Mean Difference (SMD) = −1.97, 95% CI −7.38 to 3.44, p = 0.47) and amplitude (SMD = 0.37, 95% CI −0.44 to 1.18, p = 0.37) between systemic corticosteroids and controls. When analysis compared topical corticosteroid and control, the results provided no differences in latency (Mean Difference (MD)=0.10, 95% CI −0.04 to 0.24, p = 0.16) and amplitude (SMD = 0.01, 95% CI −0.08 to 0.10, p = 0.81). In histologic outcomes, the results showed no differences in axon diameter (MD = 0.13, 95% CI −0.15 to 0.41, p = 0.37) between systemic corticosteroid and control; however, the result in myelin thickness (MD = 0.06, 95% CI 0.04 to 0.08, p < 0.05) favored control group. When comparing systemic corticosteroid with control in eye blinking, the results favored control (MD= 1.33, 95% CI 0.60 to 2.06, p = 0.0004). Conclusions: This evidence did not show potential benefits of systemic or topical corticosteroid deliveries after facial nerve neurorrhaphy in complete transection when evaluating electrophysiologic, histologic, and functional recovery outcomes in animal models.

Two birds, one stone: a surgical approach for third nerve palsy with aberrant regeneration / Tratamento cirúrgico de paralisia de terceiro nervo craniano com regeneração aberrante

ABSTRACT Aberrant regeneration in third nerve palsies, linking medial rectus contraction to the levator palpebrae muscle, is a great opportunity for surgical planning to address both the ptosis and horizontal deviation in a single procedure. We report a case of severe ptosis associated with exotropia that was successfully corrected with a single horizontal strabismus surgery owing to aberrant regeneration and discuss the basis underlying the surgical planning.

RESUMO A regeneração aberrante nas paralisias do terceiro nervo, ligando a contração do reto medial ao músculo levantador da pálpebra, é uma grande oportunidade para fazer um planejamento cirúrgico para tratar tanto a ptose quanto o desvio horizontal em um procedimento único. Relatamos uma ptose grave associada à exotropia corrigida com sucesso com uma única cirurgia de estrabismo horizontal devido à regeneração aberrante e discutimos as bases do planejamento cirúrgico.

Fotobiomodulação com LED induz melhora na funcionalidade da marcha em ratos após lesão nervosa periférica / Photobiomodulation with LED increased the gait functionality in rats submitted to peripheral nerve injury

Introdução: As lesões nervosas periféricas (LNP) podem resultar em distúrbios motores e sensoriais alterando a funcionalidade do membro afetado, porém pouco se conhece a respeito dos efeitos da fotobiomodulação (FBM) com diodo emissor de luz (LED). Objetivo: Analisar os efeitos do LED sobre a funcionalidade da marcha de ratos Wistar pós LNP. Metodologia: Ratos Wistar foram submetidos a LNP por esmagamento de ciático e analisados nos seguintes grupos experimentais: (1) Controle; (2) LNP; (3) LNP+ LED (780 nm, potência média 40 mW, exposição radiante, energia por ponto, 3,2 J sobre o nervo ciático (LEDn); (4) LNP+ LED em nervo e região do músculo envolvido (LEDnm) e (5) LNP+ LED apenas em região do músculo (LEDm). Após 7, 14, 21 e 28 dias foram realizadas as análises de marcha utilizando o Índice Funcional Ciático (IFC). Resultado: Após 7 dias, os grupos tratados com LED apresentaram uma melhora da marcha em relação ao grupo Lesão, sendo essa melhora mais pronunciada no grupo LEDn. Após 14 dias, os grupos LEDn e LEDnm apresentaram valores semelhantes ao grupo controle e após 21 e 28 dias o IFC não apresentou diferenças entre os grupos experimentais. Conclusão: O LED aumentou a funcionalidade da marcha avaliada pelo IFC após 1 e 2 semanas pós LNP, especialmente quando foi usado na região nervosa associada ou não à região muscular.

Introduction: Peripheral nerve injuries (PNI) can result in motor and sensory disturbances altering the functionality of the affected limb, however not much is known about the effects of photobiomodulation (PBM) with light emitting diode (LED). Objective: We aimed to analyze the effects of LED on the gait function of Wistar rats after PNI. Methodology: Wistar rats were submitted to PNI by sciatic crush and analyzed in the following experimental groups: (1) Control; (2) PNI; (3) PNI+ LED (780 nm, mean power 40 mW, radiant exposure, energy per spot, 3.2 J on the sciatic nerve) (LEDn); (4) LNP+ LED on nerve and involved muscle region (LEDnm) and (5) LNP+ LED only on muscle region (LEDm). After 7-, 14-, 21- and 28-days gait analyses were performed using the Sciatic Functional Index (SFI). Results: After 7 days, the groups treated with LED showed an improvement in gait compared to the PNI group, with this improvement being more pronounced in the LEDn group. After 14 days, the LEDn and LEDnm groups showed similar values to the control group and after 21 and 28 days the SFI did not show differences between the experimental groups. Conclusion: LED increased the gait functionality evaluated by SFI after 1 and 2 weeks post-PNI, especially when it was used in the nerve region associated or not with the muscle region.

Effect of Tacrolimus and Cyclosporine Immunosuppressants on Peripheral Nerve Regeneration: Systematic Review and Meta-analysis / Efeito dos imunossupressores tacrolimus e ciclosporina na regeneração de nervos periféricos: Revisão sistemática e metanálises

Abstract Peripheral nerve damage is an important cause of seeking medical attention. It occurs when the continuity of structures is interrupted and the propagation of nervous impulses is blocked, affecting the functional capacity of individuals. To assess the effects of the immunosuppressants tacrolimus and cyclosporine on the regeneration of peripheral nerves, a systematic review of the literature was carried out. The articles included were published until September 2018 and proposed to evaluate the effects of the immunosuppressants tacrolimus and cyclosporine on nerve regeneration and neuroprotection, available in the MEDLINE, EMBASE, Cochrane Library, Web of Science, Oxford Pain Relief Database, and LILACS databases. The research analysed a total of 56 articles, of which 22 were included in the meta-analysis. Statistical analysis suggests the protective effect of tacrolimus in the regeneration of the number of myelinated axons (95% confidence interval [CI]: 0.93-2.39; p< 0.01); however, such effect was not observed in relation to cyclosporine (95%CI: - 0.38-1.18; p» 0.08) It also suggests that there is a significant relationship between the use of tacrolimus and myelin thickness (95%CI» 2.00-5.71; p< 0. 01). The use of immunosuppressants in the regeneration of peripheral nerve damage promotes an increase in the number of myelinated axons in general, regardless of the administered dose. In addition, it ensures greater myelin thickness, muscle weight and recovery of the sciatic functional index. However, heterogeneity was high in most analyses performed.

Resumo As lesões nervosas periféricas são uma causa importante de busca por atendimento médico. Elas ocorrem quando há a interrupção da continuidade das estruturas e do bloqueio da propagação dos impulsos nervosos, afetando a capacidade funcional dos indivíduos. Para avaliar os efeitos dos imunossupressores tacrolimus e ciclosporina na regeneração de nervos periféricos, foi realizada uma revisão sistemática da literatura. Foram incluídos artigos publicados até setembro de 2018, que se propunham avaliar os efeitos dos imunossupressores tacrolimus e ciclosporina na regeneração nervosa e neuroproteção, disponíveis nas bases de dados MEDLINE, EMBASE, Cochrane Library, Web of Science, Oxford Pain Relief Database e LILACS. A pesquisa analisou um total de 56 artigos, dos quais 22 foram para metanálise. A análise estatística sugere o efeito protetor do tacrolimus na regeneração do número de axônios mielinizados (intervalo de confiança [IC] 95%: 0,93-2,39; p< 0,01); todavia tal efeito não foi observado em relação à ciclosporina (IC95%: - 0,38-1,18; p» 0,08). Ela também sugere haver uma relação significativa entre o uso do tacrolimus e a espessura da mielina (IC95%: 2,00-5,71; p< 0,01). O uso de imunossupressores na regeneração de lesão nervosa periférica promove um aumento no número de axônios mielinizados de forma geral, independentemente da dose administrada. Além disso, garante uma maior espessura da mielina, um maior peso muscular e restabelecimento do índice da função do nervo ciático. Todavia, a heterogeneidade foi alta na maioria das análises realizadas.

Effect of Ginsenoside Rg1 on Biological Activity of Cryopreserved Schwann Cells and Nerve Regeneration After Allograft in Rat Sciatic Nerve / 中国实验方剂学杂志

ObjectiveTo observe the effect of ginsenoside Rg1 （G-Rg1） on the biological activity of cryopreserved Schwann cells （SCs） of the rat sciatic nerve and explore the feasibility of G-Rg1 in reducing the cryopreservation-induced injury in SCs. MethodBilateral sciatic nerves of SD rats were randomly divided into a fresh group， a blank group， and five G-Rg1 groups of different doses （1×10-7， 1×10-6， 1×10-5， 1×10-4， and 1×10-3 mol·L-1）. The nerves in the blank group and the G-Rg1 groups were preserved in liquid nitrogen solutions containing 0， 1×10-7， 1×10-6， 1×10-5， 1×10-4， and 1×10-3 mol·L-1 G-Rg1 for four weeks. The apoptosis of SCs was detected by TdT-mediated dUTP-biotin nick end labeling （TUNEL）/S100 immunofluorescence staining. The expression of cysteinyl aspartate-specific protease （Caspase）-9， Caspase-3， major histocompatibility complex （MHC）-Ⅰ， and MHC-Ⅱ was detected by Western blot. Subsequently， all nerves were cultured in the incubator at 37 ℃ with 5% CO2 for 7 days. The expression of glial cell line-derived neurotrophic factor （GDNF） and nerve growth factor （NGF） was detected by Western blot. In addition， the above cryopreserved nerves in the blank group and the 1×10-6， 1×10-5， and 1×10-4 mol·L-1 G-Rg1 groups were transplanted to the Wistar rats by allografting （blank transplantation group and the 1×10-6， 1×10-5， and 1×10-4 mol·L-1 G-Rg1 transplantation groups）， and fresh sciatic nerve allograft and isograft control group were set up. Sixteen weeks after transplantation， compound muscle action potential （CMAP） and nerve conduction velocity （NCV） were measured by electrophysiology. Nerve filament （NF）200 immunofluorescence staining， transmission electron microscopy， and toluidine blue staining were used to analyze the histology of the regenerated nerves. ResultCompared with the fresh group， the blank group and the G-Rg1 groups showed increased expression of Caspase-9， Caspase-3， and the apoptosis of SCs （P<0.05，P<0.01） and decreased expression of GDNF， NGF， MHC-Ⅰ， and MHC-Ⅱ （P<0.01）. Compared with the results in the blank group， the expression of Caspase-9 and Caspase-3 decreased in the 1×10-7， 1×10-6， 1×10-5，1×10-4 mol·L-1 G-Rg1 groups （P<0.01）， and the apoptosis of SCs was reduced in the 1×10-7-1×10-4 mol·L-1 G-Rg1 groups（P<0.05，P<0.01） and increased in the 1×10-3 mol·L-1 group （P<0.05）， while the expression of GDNF and NGF increased in the 1×10-7， 1×10-6， 1×10-5，1×10-4 mol·L-1 G-Rg1 groups and decreased in the 1×10-3 mol·L-1 group （P<0.05）. There was no statistical significance in the expression of MHC-Ⅰ and MHC-Ⅱ between the blank group and the G-Rg1 groups. Compared with the 1×10-7 mol·L-1 and 1×10-3 mol·L-1 G-Rg1 groups， the 1×10-6 1×10-5， 1×10-4 mol·L-1 G-Rg1 groups showed decreased expression of Caspase-3 and the apoptosis of SCs （P<0.05，P<0.01） and increased expression of GDNF and NGF （P<0.05，P<0.01）. There was no statistical significance in MHC-Ⅰ and MHC-Ⅱ expression among G-Rg1 groups. Sixteen weeks after transplantation， compared with the isograft group， the blank transplantation group and the G-Rg1 transplantation groups showed decreased CMAP， NCV， myelin sheath thickness， and number of myelinated nerve fibers （P<0.01）， and the 1×10-6 and 1×10-4 mol·L-1 G-Rg1 transplantation groups showed decreased NF200 （P<0.01）. Compared with the allograft group， the blank transplantation group and the G-Rg1 transplantation groups showed increased CMAP， NCV， NF200， myelin sheath thickness， and number of myelinated nerve fibers （P<0.05，P<0.01）. Compared with the blank transplantation group， the G-Rg1 transplantation groups showed increased CMAP， NCV， NF200， myelin sheath thickness， and number of myelinated nerve fibers （P<0.05，P<0.01）. Among all groups of G-Rg1 transplantation， each index of the 1×10-5 mol·L-1 G-Rg1 transplantation group was superior to that of the 1×10-4 and 1×10-6 mol·L-1 G-Rg1 transplantation group （P<0.05）. ConclusionG-Rg1 at a certain centration can maintain the biological activity of cryopreserved SCs of rat sciatic nerve， alleviate the cryopreservation-induced injury of rat sciatic nerve， and promote nerve regeneration after allograft.