A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong disability.Currently,there are no FDA-approved therapies available to promote nerve regeneration.Tacrolimus accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve surgery.The authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug exposure.Tacrolimus is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 days.Size and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible byproducts.Tacrolimus released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic delivery.Given its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

Effects of subcutaneous implant of peripheral nerve allograft on the regeneration of defected sciatic nerve

BAEKGROUND： Some experimental studies demonstrate that subcutaneous implant of allograft can significantly decrease lymphocyte infiltration and reduce immunological reaction. However, compared with autologous nerve grafting, what is the effect of nerve regeneration after repair？OB]EETIVE： To observe the local nervous status of the detected part of sciatic nerve repaired through subcutaneously implanting peripheral nerve allograft, and compare the effect with fresh autologous nerve grafting.DESTGN ： Contrast observation.SETTING ： Departments of Orthopaedics of Zhengzhou Fifth People＇s Hospital and First Hospital Affiliated to Chongqing Medical University.MATEREALS ： Totally 30 healthy adult Wistar male rats, with body mass of （200±20）g, were enrolled. Optical microscope （Olympus biological microscope BHS, Japan）, Electron microscope （H-600, Japan）,CM-2000 biomedical image analysis system （CM-2000,Beihang） and myoelectricity scanner （KEYPOINT, Denmark） were used in this experiment.METHODS ： This experiment was carried out in the Orthopaedic Laboratory of Chongqing Medical University between October 2000 and April 2002. ① Six rats were chosen as the donors for allogenic nerve grafting, and 15 mm sciatic nerve segment was chosen as graft. The other rats were randomly divided into two groups： allogenic nerve grafting group and autologous nerve grafting group, with 12 rats in each group. In the allogenic nerve grafting group, a skin incision was made on the posterior side of right thigh, and subcutaneous blunt dissection was performed prorsally a little, then allograft was implanted. Two weeks later, sciatic nerve was exposed at the posterior side of left thigh and cut respectively at 5 mm and another 10 mm away from pelvis. The donor nerve （with connective tissue veil） implanted subcutaneously on the right thigh was taken out. Sectioned connective tissue at the proximal end was trimmed and that at the distal end as done but reserved 10 mm in length, and inosculated antegradely at the nerve defect on the left side with 11/0 nylon line. Twelve rats in autologous nerve grafting group underwent a 10 mm sciatic nerve defect inci- sion on the right thigh and implant of fresh sciatic nerve from left thigh. The incision on the left thigh was repaired in situ. ②2,4,8 and 14 weeks after grafting, the nerve specimen of anastomosis segment was observed under optical microscope. Fourteen weeks after grafting, the ultrathin section of distal sciatic nerve was observed under transmission electron microscope. The number and size of regenerated axons at the cross section of anastomosis of proximal and distal sciatic nerve were analyzed with biomedical image analysis system. Neuroelectrophysiological change of in vivo sciatic nerve was detected with myoelectricity scanner.③ t test was used in the comparison of difference of measurement data.MAZN OUTCOME MEASURES ： ① Observation of anastomosis part of sciatic nerve under optical and electron microscopes in the two groups. ② Comparison of motor nerve conduction velocity, latent period and action potential peak as well as the number and size of cross-section of anastomosis part of proximal and distal sciatic nerve between two groups.RESULTS： ①Observation under optical microscope：Two weeks after grafting, neve axon of repaired region broke and medullary sheath denatured in the allogenic nerve grafting group and autologous nerve grafting group. At the same time, vascular engorgement and a little lymphocytes infiltration were found in the autologous nerve grafting group, but those were found worsened in the allogenic nerve grafting group. Four weeks after grafting, the intensity of the inflammatory reaction was similar between two groups, some collagen fibers at the proximal end proliferated; 8 weeks after grafting, the inflammatory reaction ended basically and the collagen fibers proliferated obviously in the two groups. ② Observation under electron microscope： Fourteen weeks after grafting, the structure of epineurium was in integrity and there were no obvious differences in perineurium and endonurium between two groups. A large number of myelinated nerve fibers and a few unmyelinated nerve fibers regenerated. The structure of myelin sheath was in integrity. ③The number and size of regenerated axons of anastomosis of proximal and distal sciatic nerve had no significant difference 14 weeks after grafting [（575.500±7.495） vs（585.700±11.172） axons/visual field ; （389.300±49.073） vs （407.600±0.283） axons/visual field;（6 423.830±119.911 ） vs （6 695.36± 84.287） μm^2/visual field = （ 5 980.110±74.572） vs（5 980.110±74.572） μm^2/visual field] （P 〉 0.05）. ④ Neuroelectrophysiological examination showed that there were no significant differences in motor nerve evoked potential latent pedod[（1.420±0.346）vs （1.237±0.250） ms] , motor nerve conduction velocity [（ 12.120±0.906 ） vs（13.020±0.599） m/s]and latent period of sciatic nerve [（0.500±0.380）vs （1.250±1.067） mV] of rats between two groups （P 〉 0.05）.CONCLUSTON： Although subcutaneous implant of peripheral nerve allograft has some inflammatory reactions, no obvious rejection is found. Repair results of two groups show that subcutaneous implant of allograft can promote nerve regeneration, which is similar to autologous nerve grafting.

Neuregulin 1 isoforms could be an effective therapeutic candidate to promote peripheral nerve regeneration

Traumatic injuries of peripheral nerves represent common casualties and their social impact is considerably high. Although peripheral nerves retain a good regeneration potential, the clinical outcome after nerve lesion is far from being satisfactory and functional recovery is almost never complete, especially in the case of large nerve defects, that result in loss or diminished sensitivity and/or motor activity of the innervated target organs. Therefore, to improve the outcome after nerve damage, or in peripheral neuropathies, there is a need for further research in nerve repair and regeneration to identify factors that promote axonal regrowth, remvelination and target reinnervation.

Rho/ROCK pathway and neural regeneration: a potential therapeutic target for central nervous system and optic nerve damage

Rho-associated kinase (ROCK) is a serine/threonine kinase and one of the major downstream effectors of the small GTPase RhoA. The Rho/ROCK pathway is closely related to the pathogenesis of several central nervous system (CNS) disorders, and involved in many aspects of neuronal functions including neurite outgrowth and retraction. In the adult CNS, the damaged neuron regeneration is very difficult due to the presence of myelin-associated axon growth inhibitors such as Nogo, myelin-associated glycoprotein (MAG) and oligodendrocyte-myelin glycoprotein (Omgp), etc. The effects of these axon growth inhibitors are reversed by blocking the Rho/ROCK pathway 47 vitro, and the inhibition of Rho/ROCK pathway can promote axon regeneration and functional recovery in the injured CNS in viva In addition, the therapeutic effects of the Rho/ROCK inhibitors have also been demonstrated in some animal models and the Rho/ROCK pathway becomes an attractive target for the development of drugs for treating CNS disorders. In this review, we summarized on the effect of the Rho and the downstream factor ROCK in neural regeneration, and the potential therapeutic effect of Rho/ROCK inhibitors in the survival and axonal regeneration of retinal ganglion cell was also discussed.

Anastomotic stoma coated with chitosan film as a betamethasone dipropionate carrier for peripheral nerve regeneration

Scar hyperplasia at the suture site is an important reason for hindering the repair effect of peripheral nerve injury anastomosis. To address this issue, two repair methods are often used. Biological agents are used to block nerve sutures and the surrounding tissue to achieve phys- ical anti-adhesion effects. Another agent is glucocorticosteroid, which can prevent scar growth by inhibiting inflammation. However, the overall effect of promoting regeneration of the injured nerve is not satisfactory. In this regard, we envision that these two methods can be combined and lead to shared understanding for achieving improved nerve repair. In this study, the right tibial nerve was transected 1 cm above the knee to establish a rat tibial nerve injury model. The incision was directly sutured after nerve transection. The anastomotic stoma was coated with 0.5 × 0.5 cm^2 chitosan sheets with betamethasone dipropionate. At 12 weeks after injury, compared with the con- trol and poly （D, L-lactic acid） groups, chitosan-betamethasone dipropionate film slowly degraded with the shape of the membrane still intact. Further, scar hyperplasia and the degree of adhesion at anastomotic stoma were obviously reduced, while the regenerated nerve fiber structure was complete and arranged in a good order in model rats. Electrophysiological study showed enhanced compound muscle action potential. Our results confirm that chitosan-betamethasone dipropionate film can effectively prevent local scar hyperplasia after tibial nerve repair and promote nerve regeneration.

Neurotrophic effects of dental pulp stem cells in repair of peripheral nerve after crush injury

BACKGROUND Nerve diseases and injuries,which are usually accompanied by motor or sensory dysfunction and disorder,impose a heavy burden upon patients and greatly reduce their quality of life.Dental pulp stem cells(DPSCs),derived from the neural crest,have many characteristics that are similar to those of neural cells,indicating that they can be an ideal source for neural repair.AIM To explore the potential roles and molecular mechanisms of DPSCs in crushed nerve recovery.METHODS DPSCs were isolated,cultured,and identified by multilineage differentiation and flow cytometry.Western blot and immunofluorescent staining were applied to analyze the expression levels of neurotrophic proteins in DPSCs after neural induction.Then,we collected the secretions of DPSCs.We analyzed their effects on RSC96 cell proliferation and migration by CCK8 and transwell assays.Finally,we generated a sciatic nerve crush injury model in vivo and used the sciatic function index,walking track analysis,muscle weight,and hematoxylin&eosin(H&E)staining to further evaluate the nerve repair ability of DPSCs.RESULTS DPSCs highly expressed several specific neural markers,including GFAP,S100,Nestin,P75,and NF200,and were inclined toward neural differentiation.Furthermore,neural-induced DPSCs(N-DPSCs)could express neurotrophic factors,including NGF,BDNF,and GDNF.The secretions of N-DPSCs could enhance the proliferation and migration of Schwann cells.In vivo,both DPSC and N-DPSC implants alleviated gastrocnemius muscle atrophy.However,in terms of anatomy and motor function,as shown by H&E staining,immunofluorescent staining,and walking track analyses,the repair effects of N-DPSCs were more sustained,potent,and effective than those of DPSCs and the controls.CONCLUSION In summary,this study demonstrated that DPSCs are inclined to differentiate into neural cells.N-DPSCs express neurotrophic proteins that could enhance the proliferation and migration of SCs.Furthermore,our results suggested that NDPSCs could help crushed nerves with functional recovery and anatomical repair in vivo.Thus,DPSCs or N-DPSCs could be a promising therapeutic cell source for peripheral nerve repair and regeneration.

Polydopamine-modified chitin conduits with sustained release of bioactive peptides enhance peripheral nerve regeneration in rats

The introduction of neurotrophic factors into injured peripheral nerve sites is beneficial to peripheral nerve regeneration.However,neurotrophic facto rs are rapidly degraded in vivo and obstruct axonal regeneration when used at a supraphysiological dose,which limits their clinical benefits.Bioactive mimetic peptides have been developed to be used in place of neurotrophic factors because they have a similar mode of action to the original growth fa ctors and can activate the equivalent receptors but have simplified sequences and structures.In this study,we created polydopamine-modified chitin conduits loaded with brain-derived neurotrophic factor mimetic peptides and vascular endothelial growth fa ctor mimetic peptides(Chi/PDA-Ps).We found that the Chi/PDA-Ps conduits were less cytotoxic in vitro than chitin conduits alone and provided sustained release of functional peptides.In this study,we evaluated the biocompatibility of the Chi/P DA-Ps conduits.Brain-derived neurotrophic factor mimetic peptide and vascular endothelial growth fa ctor mimetic peptide synergistically promoted prolife ration of Schwann cells and secretion of neurotrophic factors by Schwann cells and attachment and migration of endothelial cells in vitro.The Chi/P DA-Ps conduits were used to bridge a 2 mm gap between the nerve stumps in rat models of sciatic nerve injury.We found that the application of Chi/PDA-Ps conduits could improve the motor function of rats and reduce gastrocnemius atrophy.The electrophysiological results and the microstructure of regenerative nerves showed that the nerve conduction function and re myelination was further resto red.These findings suggest that the Chi/PDA-Ps conduits have great potential in peripheral nerve injury repair.

Restorative effect and mechanism of mecobalamin on sciatic nerve crush injury in mice

Mecobalamin, a form of vitamin B12 containing a central metal element （cobalt）, is one of the most important mediators of nervous system function. In the clinic, it is often used to accelerate recovery of peripheral nerves, but its molecular mechanism remains unclear. In the present study, we performed sciatic nerve crush injury in mice, followed by daily intraperitoneal administra-tion of mecobalamin （65 μg/kg or 130 μg/kg） or saline （negative control）. Walking track analysis, histomorphological examination, and quantitative real-time PCR showed that mecobalamin signiifcantly improved functional recovery of the sciatic nerve, thickened the myelin sheath in myelinated nerve ifbers, and increased the cross-sectional area of target muscle cells. Further-more, mecobalamin upregulated mRNA expression of growth associated protein 43 in nerve tissue ipsilateral to the injury, and of neurotrophic factors （nerve growth factor, brain-derived nerve growth factor and ciliary neurotrophic factor） in the L4–6 dorsal root ganglia. Our ifndings indicate that the molecular mechanism underlying the therapeutic effect of mecobalamin after sciatic nerve injury involves the upregulation of multiple neurotrophic factor genes.

Efficacy and safety of nerve growth factor for the treatment of neurological diseases:a meta-analysis of 64 randomized controlled trials involving 6,297 patients

OBJECTIVE： China is the only country where nerve growth factor is approved for large-scale use as a clinical medicine. More than 10 years ago, in 2003, nerve growth factor injection was listed as a national drug. The goal of this article is to evaluate comprehensively the efficacy and safety of nerve growth factor for the treatment of neurological diseases. DATA RETRIEVAL： A computer-based retrieval was performed from six databases, including the Cochrane Library, PubMed, EMBASE, Sino Med, CNKI, and the VIP database, searching from the clinical establishment of nerve growth factor for treatment until December 31, 2013. The key words for the searches were ＂nerve growth factor, randomized controlled trials＂ in Chinese and in English. DATA SELECTION： Inclusion criteria： any study published in English or Chinese referring to randomized controlled trials of nerve growth factor; patients with neurological diseases such as peripheral nerve injury, central nerve injury, cranial neuropathy, and nervous system infections; patients older than 7 years; similar research methods and outcomes assessing symptoms; and measurement of nerve conduction velocities. The meta-analysis was conducted using Review Manager 5.2.3 software. MAIN OUTCOME MEASURES： The total effective rate, the incidence of adverse effects, and the nerve conduction velocity were recorded for each study. RESULTS： Sixty-four studies involving 6,297 patients with neurological diseases were included. The total effective rate in the group treated with nerve growth factor was significantly higher than that in the control group （P 〈 0.0001, RR： 1.35, 95%CI： 1.30-1.40）. The average nerve conduction velocity in the nerve growth factor group was significantly higher than that in the control group （P 〈 0.00001, MD. 4.59 m/s, 95%CI： 4.12-5.06）. The incidence of pain or sclero- ma at the injection site in the nerve growth factor group was also higher than that in the control group （P 〈 0.00001, RR： 6.30, 95%CI： 3.53-11.27）, but such adverse effects were mild. CONCLUSION： Nerve growth factor can significantly improve nerve function in patients with nervous system disease and is safe and effective.

Immediate effects of scalp acupuncture with twirling reinforcing manipulation on hemiplegia following acute ischemic stroke: a hidden association study

Data mining has the potential to provide information for improving clinical acupuncture strategies by uncovering hidden rules between acupuncture manipulation and therapeutic effects in a data set. In this study, we performed acupuncture on 30 patients with hemiplegia due to acute ischemic stroke. All participants were pre-screened to ensure that they exhibited immediate responses to acupuncture. We used a twirling reinforcing acupuncture manipulation at the specific lines between the bilateral Baihui（GV20） and Taiyang（EX-HN5）. We collected neurologic deficit score, simplified Fugl-Meyer assessment score, muscle strength of the proximal and distal hemiplegic limbs, ratio of the maximal H-reflex to the maximal M-wave（Hmax/Mmax）, muscle tension at baseline and immediately after treatment, and the syndromes of traditional Chinese medicine at baseline. We then conducted data mining using an association algorithm and an artificial neural network backpropagation algorithm. We found that the twirling reinforcing manipulation had no obvious therapeutic difference in traditional Chinese medicine syndromes of ＂Deficiency and Excess＂. The change in the muscle strength of the upper distal and lower proximal limbs was one of the main factors affecting the immediate change in Fugl-Meyer scores. Additionally, we found a positive correlation between the muscle tension change of the upper limb and Hmax/Mmax immediate change, and both positive and negative correlations existed between the muscle tension change of the lower limb and immediate Hmax/Mmax change. Additionally, when the difference value of muscle tension for the upper and lower limbs was 〉 0 or 〈 0, the difference value of Hmax/Mmax was correspondingly positive or negative, indicating the scalp acupuncture has a bidirectional effect on muscle tension in hemiplegic limbs. Therefore, acupuncture with twirling reinforcing manipulation has distinct effects on acute ischemic stroke patients with different symptoms or stages of disease. Improved muscle tension in the upper and lower limbs, reflected by the variation in the Hmax/Mmax ratio, is crucial for recovery of motor function from hemiplegia.

Houshiheisan and its components promote axon regeneration after ischemic brain injury

Houshiheisan,a classic prescription in traditional Chinese medicine,contains Flos Chrysanthemi,Radix Saposhnikoviae,Ramulus Cinnamomi,Rhizoma Chuanxiong,Radix et Rhizoma Asari,Radix Platycodonis,Rhizoma Atractylodis macrocephalae,Poria,Rhizoma Zingiberis,Radix Angelicae sinensis,Radix et Rhizoma Ginseng,Radix Scutellariae and Concha Ostreae.According to traditional Chinese medicine theory,Flos Chrysanthemi,Radix Saposhnikoviae,Ramulus Cinnamomi,Rhizoma Chuanxiong,Radix et Rhizoma Asari and Radix Platycodonis are wind-dispelling drugs;Rhizoma Atractylodis macrocephalae,Poria,Rhizoma Zingiberis,Radix Angelicae sinensis and Radix et Rhizoma Ginseng are deficiency-nourishing drugs.A large number of randomized controlled trials have shown that Houshiheisan is effective in treating stroke,but its mechanism of action is unknown.Axonal remodeling is an important mechanism in neural protection and regeneration.Therefore,this study explored the effect and mechanism of action of Houshiheisan on the repair of axons after cerebral ischemia.Rat models of focal cerebral ischemia were established by ligating the right middle cerebral artery.At 6 hours after model establishment,rats were intragastrically administered 10.5 g/kg Houshiheisan or 7.7 g/kg wind-dispelling drug or 2.59 g/kg deficiency-nourishing drug.These medicines were intragastrically administered as above every 24 hours for 7 consecutive days.Houshiheisan,and its wind-dispelling and deficiency-nourishing components reduced the neurological deficit score and ameliorated axon and neuron lesions after cerebral ischemia.Furthermore,Houshiheisan,and its wind-dispelling and deficiency-nourishing components decreased the expression of proteins that inhibit axonal remodeling：amyloid precursor protein,neurite outgrowth inhibitor protein A（Nogo-A）,Rho family small GTPase A（Rho A） and Rho-associated kinase 2（Rock2）,and increased the expression of growth associated protein-43,microtubule-associated protein-2,netrin-1,Ras-related C3 botulinum toxin substrate 1（Rac1） and cell division cycle 42（Cdc42）.The effect of Houshiheisan was stronger than wind-dispelling drugs or deficiency-nourishing drugs alone.In conclusion,Houshiheisan,and wind-dispelling and deficiency-nourishing drugs promote the repair of axons and nerve regeneration after cerebral ischemia through Nogo-A/Rho A/Rock2 and Netrin-1/Rac1/Cdc42 signaling pathways.These effects are strongest with Houshiheisan.

Effects of Ginkgo biloba extract EGb761 on neural differentiation of stem cells offer new hope for neurological disease treatment

Stem cell transplantation has brought new hope for the treatment of neurological diseases.The key to stem cell therapy lies in inducing the specific differentiation of stem cells into nerve cells.Because the differentiation of stem cells in vitro and in vivo is affected by multiple factors,the final differentiation outcome is strongly associated with the microenvironment in which the stem cells are located.Accordingly,the optimal microenvironment for inducing stem cell differentiation is a hot topic.EGb761 is extracted from the leaves of the Ginkgo biloba tree.It is used worldwide and is becoming one of the focuses of stem cell research.Studies have shown that EGb761 can antagonize oxygen free radicals,stabilize cell membranes,promote neurogenesis and synaptogenesis,increase the level of brain-derived neurotrophic factors,and replicate the environment required during the differentiation of stem cells into nerve cells.This offers the possibility of using EGb761 to induce the differentiation of stem cells,facilitating stem cell transplantation.To provide a comprehensive reference for the future application of EGb761 in stem cell therapy,we reviewed studies investigating the influence of EGb761 on stem cells.These started with the composition and neuropharmacology of EGb761,and eventually led to the finding that EGb761 and some of its important components play important roles in the differentiation of stem cells and the protection of a beneficial microenvironment for stem cell transplantation.

Protective effects of organic extracts of Alpinia oxyphylla against hydrogen peroxide-induced cvtotoxicitv in PC12 cells

Alpinia oxyphylla,a traditional herb,is widely used for its neuroprotective,antioxidant and memory-improving effects.However,the neuroprotective mechanisms of action of its active ingredients are unclear.In this study,we investigated the neuroprotective effects of various organic extracts of Alpinia oxyphylla on PC12 cells exposed to hydrogen peroxide-induced oxidative injury in vitro.Alpinia oxyphylla was extracted three times with 95%ethanol(representing extracts 1–3).The third 95%ethanol extract was dried and resuspended in water,and then extracted successively with petroleum ether,ethyl acetate and n-butanol(representing extracts 4–6).The cell counting kit-8 assay and microscopy were used to evaluate cell viability and observe the morphology of PC12 cells.The protective effect of the three ethanol extracts(at tested concentrations of 50,100 and 200μg/mL)against cytotoxicity to PC12 cells increased in a concentration-dependent manner.The ethyl acetate,petroleum ether and n-butanol extracts(each tested at 100,150 and 200μg/mL)had neuroprotective effects as well.The optimum effective concentration ranged from 50–200μg/mL,and the protective effect of the ethyl acetate extract was comparatively robust.These results demonstrate that organic extracts of Alpinia oxyphylla protect PC12 cells against apoptosis induced by hydrogen peroxide.Our findings should help identify the bioactive neuroprotective components in Alpinia oxyphylla.

Electroacupuncture pretreatment exhibits antidepressive effects by regulating hippocampal proteomics in rats with chronic restraint stress

The clinical effect of electroacupuncture on depression is widely recognized. However, the signal transduction pathways and target proteins involved remain unclear. In the present study, rat models of chronic restraint stress were used to explore the mechanism by which electroacupuncture alleviates depression. Rats were randomly divided into control, model, and electroacupuncture groups. Chronic restraint stress was induced in the model and electroacupuncture groups by restraining rats for 28 days. In the electroacupuncture group, electroacupuncture pretreatment at Baihui（GV20） and Yintang（GV29） acupoints was performed daily（1 m A, 2 Hz, discontinuous wave, 20 minutes） prior to restraint for 28 days. Open field tests and body weight measurements were carried out to evaluate the depressive symptoms at specific time points. On day 28, the crossing number, rearing number, and body weights of the model group were significantly lower than those in the control group. Behavior test results indicated that rat models of depressive-like symptoms were successfully established by chronic restraint stress combined with solitary raising. On day 28, an isobaric tag for a relative and absolute quantitation-based quantitative proteomic approach was performed to identify differentially expressed proteins in hippocampal samples obtained from the model and electroacupuncture groups. The potential function of these differential proteins was predicted through the use of the Cluster of Orthologous Groups of proteins（COG） database. Twenty-seven differential proteins（uncharacteristic proteins expected） were selected from the model and electroacupuncture groups. In addition to unknown protein functions, COG are mainly concentrated in general prediction function, mechanism of signal transduction, amino acid transport and metabolism groups. This suggests that electroacupuncture improved depressive-like symptoms by regulating differential proteins, and most of these related proteins exist in nerve cells.

Protective effects of components of the Chinese herb grassleaf sweetflag rhizome on PC12 cells incubated with amyloid-beta42

The major ingredients of grassleaf sweetflag rhizome are β-asarone and eugenol, which can cross the blood-brain barrier and protect neurons. This study aimed to observe the neuroprotective effects and mechanisms of β-asarone and eugenol, components of the Chinese herb grassleaf sweetflag rhizome, on PC12 cells. First, PC12 cells were cultured with different concentrations（between 1 × 10–10 M and 1 × 10–5 M） of β-asarone and eugenol. Survival rates of PC12 cells were not significantly affected. Second, PC12 cells incubated with amyloid-beta42, which reduced cell survival, were cultured under the same conditions（1 × 10–6 M β-asarone and eugenol）. The survival rates of PC12 cells significantly increased, while expression levels of the m RNAs for the pro-apoptotic protein Bax decreased, and those for the anti-apoptotic protein Bcl m RNA increased. In addition, the combination of β-asarone with eugenol achieved better results than either component alone. Our experimental findings indicate that both β-asarone and eugenol protect PC12 cells through inhibiting apoptosis, and that the combination of the two is better than either alone.

Effects of chitosan on dental bone repair

Objectives: Bone defects following tumor resection and osteolysis due to dental and bone lesions and periodentium tissue disorders are serious challenges. One of these materials used is chitosan, a derivative of crustaceans’ exoskeleton. The aim of this study was to assess effects of chitosan on socket repair after dental extraction. Methods: Twenty four dental sockets of 15-24 years old patients were visited by a maxillofacial surgeon for extracting premolar teeth for orthodontic purposes. The sockets in one side were filled-in by chitosan. In the other side, the sockets were left unfilled. After 10 weeks, periapical radiographs were obtained from the repair sites, were digitalized and then evaluated for densitometry using Adobe Photoshop Software. Each socket was divided into coronal, middle and apical. Dental density of each socket in case and control groups was recorded. The density of regenerated bone was compared against the maximum bone density of each individual. Wilcoxon signed range test and paired t-test were used for data analysis. Results: Bone density in middle and apical sections in case group was significantly more than control group. In apical section in case group regenerated bone reached up to 98.2% of normal bone density. In each patient, the bone density in epical and middle sections was increase 29.3% and 10.8% of normal bone density. Conclusions: Chitosan significantly increased bone density in epical and middle sections. Chitosan can be used for bone repair in cases of bone loss. Various densitometry studies for evaluating chitosan effects in different bone defects are suggested.

Biopolymer-nanotube nerve guidance conduit drug delivery for peripheral nerve regeneration:In vivo structural and functional assessment

Peripheral nerve injuries account for roughly 3%of all trauma patients with over 900,000 repair procedures annually in the US.Of all extremity peripheral nerve injuries,51%require nerve repair with a transected gap.The current gold-standard treatment for peripheral nerve injuries,autograft repair,has several shortcomings.Engineered constructs are currently only suitable for short gaps or small diameter nerves.Here,we investigate novel nerve guidance conduits with aligned microchannel porosity that deliver sustained-release of neurogenic 4-aminopyridine(4-AP)for peripheral nerve regeneration in a critical-size(15 mm)rat sciatic nerve transection model.The results of functional walking track analysis,morphometric evaluations of myelin development,and histological assessments of various markers confirmed the equivalency of our drug-conduit with autograft controls.Repaired nerves showed formation of thick myelin,presence of S100 and neurofilament markers,and promising functional recovery.The conduit’s aligned microchannel architecture may play a vital role in physically guiding axons for distal target reinnervation,while the sustained release of 4-AP may increase nerve conduction,and in turn synaptic neurotransmitter release and upregulation of critical Schwann cell neurotrophic factors.Overall,our nerve construct design facilitates efficient and efficacious peripheral nerve regeneration via a drug delivery system that is feasible for clinical applications.

功能性水凝胶在创伤性脑损伤组织修复中的作用

背景:目前临床上传统的给药途径(口服或静脉注射)面临难以透过血脑屏障问题,对于开放性重度创伤性脑损伤的临床治疗结果往往低于预期。水凝胶是一类极为亲水的三维网络结构凝胶,在水中迅速溶胀并在此溶胀状态可以保持。目前有部分实验应用可注射性功能水凝胶注射植入损伤部位以达到修复受损脑组织的目的,但这一治疗策略尚未应用于临床。目的:分析功能性水凝胶在创伤性脑损伤后组织修复中的作用,讨论水凝胶通过不同作用方式促进创伤性脑损伤后的神经组织再生,以期为创伤性脑损伤的临床治疗和基础研究提出新的思路。方法:以“hydrogels,functional hydrogel,composite hydrogels,traumatic brain injury,tissue repair,neural regeneration”“功能性水凝胶,创伤性脑损伤,组织修复,神经再生”为关键词在PubMed、Web of Science、中国知网和万方数据库检索2000年8月至2024年3月的相关文献。制定纳入和排除标准,通过阅读文献标题、摘要及全文内容进行筛选,最终纳入60篇相关文献进行综述。结果与结论:①基于分子设计的水凝胶可以模拟神经微结构,促进再生修复,模拟神经血管单元促进血管再生。②基于联合药物治疗原则的水凝胶可以递送内源性神经调控因子,包裹药物促进神经再生。③基于搭载干细胞恢复策略的水凝胶可以作为分子支架递送细胞治疗。④未来研究学者们还需进一步探索神经组织修复相关的功能性水凝胶,为创伤性脑损伤患者的治疗功能重建提供有效策略。

Nanoparticles for the treatment of spinal cord injury

Spinal cord injuries lead to significant loss of motor, sensory, and autonomic functions, presenting major challenges in neural regeneration. Achieving effective therapeutic concentrations at injury sites has been a slow process, partly due to the difficulty of delivering drugs effectively. Nanoparticles, with their targeted delivery capabilities, biocompatibility, and enhanced bioavailability over conventional drugs, are garnering attention for spinal cord injury treatment. This review explores the current mechanisms and shortcomings of existing treatments, highlighting the benefits and progress of nanoparticle-based approaches. We detail nanoparticle delivery methods for spinal cord injury, including local and intravenous injections, oral delivery, and biomaterial-assisted implantation, alongside strategies such as drug loading and surface modification. The discussion extends to how nanoparticles aid in reducing oxidative stress, dampening inflammation, fostering neural regeneration, and promoting angiogenesis. We summarize the use of various types of nanoparticles for treating spinal cord injuries, including metallic, polymeric, protein-based, inorganic non-metallic, and lipid nanoparticles. We also discuss the challenges faced, such as biosafety, effectiveness in humans, precise dosage control, standardization of production and characterization, immune responses, and targeted delivery in vivo. Additionally, we explore future directions, such as improving biosafety, standardizing manufacturing and characterization processes, and advancing human trials. Nanoparticles have shown considerable progress in targeted delivery and enhancing treatment efficacy for spinal cord injuries, presenting significant potential for clinical use and drug development.

Pathogenesis, diagnosis, and treatment of epilepsy: electromagnetic stimulation-mediated neuromodulation therapy and new technologies

Epilepsy is a severe,relapsing,and multifactorial neurological disorder.Studies regarding the accurate diagnosis,prognosis,and in-depth pathogenesis are crucial for the precise and effective treatment of epilepsy.The pathogenesis of epilepsy is complex and involves alterations in variables such as gene expression,protein expression,ion channel activity,energy metabolites,and gut microbiota composition.Satisfactory results are lacking for conventional treatments for epilepsy.Surgical resection of lesions,drug therapy,and non-drug interventions are mainly used in clinical practice to treat pain associated with epilepsy.Non-pharmacological treatments,such as a ketogenic diet,gene therapy for nerve regeneration,and neural regulation,are currently areas of research focus.This review provides a comprehensive overview of the pathogenesis,diagnostic methods,and treatments of epilepsy.It also elaborates on the theoretical basis,treatment modes,and effects of invasive nerve stimulation in neurotherapy,including percutaneous vagus nerve stimulation,deep brain electrical stimulation,repetitive nerve electrical stimulation,in addition to non-invasive transcranial magnetic stimulation and transcranial direct current stimulation.Numerous studies have shown that electromagnetic stimulation-mediated neuromodulation therapy can markedly improve neurological function and reduce the frequency of epileptic seizures.Additionally,many new technologies for the diagnosis and treatment of epilepsy are being explored.However,current research is mainly focused on analyzing patients’clinical manifestations and exploring relevant diagnostic and treatment methods to study the pathogenesis at a molecular level,which has led to a lack of consensus regarding the mechanisms related to the disease.