Rat Sciatic Nerve Injury Research Articles

Impact of Platelet-Rich Plasma on Sciatic Nerve Injury in Rats: HSP 70 Expression and Histological Changes in the Anterior Horn of the Spinal Cord

Peripheral nerve injuries are a significant and growing cause of disability worldwide, as reported by the World Health Organization (WHO). These injuries initiate complex cellular and molecular responses, including the activation of protective pathways that upregulate proteins such as Heat Shock Protein 70 (HSP 70), which plays a crucial role in neuroprotection and the inhibition of neuronal apoptosis. This study investigates the effects of Platelet-Rich Plasma (PRP) on peripheral nerve regeneration, focusing on neuron density, Nissl body presence, and HSP 70 expression as key indicators of recovery. The study utilized 36 rat spinal cord samples, divided into two main groups based on the evaluation time points, day 7 and day 42 post-injury. Each time point group was further subdivided into three: control, sciatica injury, and sciatica injury treated with PRP. Results demonstrated that PRP treatment significantly enhances peripheral nerve regeneration. This was evidenced by increased neuron density, improved Nissl body formation, and a modulation of HSP 70 expression levels, leading to accelerated recovery of motor function, particularly noticeable by day 7 post-injury. These findings suggest that PRP could be a promising therapeutic option for enhancing nerve regeneration and functional recovery after peripheral nerve injuries.

Electrospun PCL Nerve Wrap Coated with Graphene Oxide Supports Axonal Growth in a Rat Sciatic Nerve Injury Model.

Background/Objectives: Peripheral nerve injuries (PNIs) are a debilitating problem, resulting in diminished quality of life due to the continued presence of both chronic and acute pain. The current standard of practice for the repair of PNIs larger than 10 mm is the use of autologous nerve grafts. Autologous nerve grafts have limitations that often result in outcomes that are not sufficient to remove motor and sensory impairments. Bio-mimetic nanocomposite scaffolds combined with mesenchymal stem cells (MSCs) represent a promising approach for PNIs. In this study, we investigated the potential of an electrospun wrap of polycaprolactone (PCL) + graphene oxide (GO), with and without xenogeneic human adipose tissue-derived MSCs (hADMSCs) to use as a platform for neural tissue engineering. Methods: We evaluated, in vitro and in vivo, the potential of the nerve wrap in providing support for axonal growth. To establish the rat sciatic nerve defect model, a 10 mm long limiting defect was created in the rat sciatic nerve of 18 Lewis rats. Rats treated with the nanocomposites were compared with autograft-treated defects. Gait, histological, and muscle analyses were performed after sacrifice at 12 weeks post-surgery. Results: Our findings demonstrate that hADMSCs had the potential to transdifferentiate into neural lineage and that the nanocomposite successfully delivered hADMSCs to the injury site. Histologically, we show that the PCL + GO nanocomposite with hADMSCs is comparable to the autologous nerve graft, to support and guide axonal growth. Conclusions: The novel PCL + GO nerve wrap and hADMSCs used in this study provide a foundation on which to build upon and generate future strategies for PNI repair.

Inhibition of KIF5b-mediated Nav1.8 transport by ropivacaine contributes to axonal regeneration following sciatic nerve injury in rats

Peripheral nerve injury (PNI), typically caused by traumatic accidents or medical events, is currently one of the most common diseases that leads to limb disability. After PNI, tetrodotoxin-resistant voltage-gated sodium channel Nav1.8 is upregulated at the lesion site. Our earlier study suggested that ropivacaine promotes axon regrowth by regulating Nav1.8-mediated macrophage signaling. Nevertheless, the mechanism of ropivacaine in regulation of Nav1.8 expression remains incompletely understood. Kinesin family 5b (KIF5b) was reported to mediate the Nav1.8 axonal transport from dorsal root ganglia (DRGs) to lesion site. Herein, we investigated whether ropivacaine promotes axon regeneration through inhibition of KIF5b-mediated Nav1.8 transport. Reduced levels of KIF5b and Nav1.8 in DRGs coincide with their increase at the lesion site. Nav1.8 mRNA was significantly increased at the lesion site but not in DRGs. Surprisingly, ropivacaine reversed the alterations of Nav1.8 and KIF5b protein expression without affecting Nav1.8 mRNA level. Due to KIF5b overexpression in DRGs, Nav1.8 protein level was significantly decreased in DRGs and increased at the lesion site. We also found KIF5b overexpression significantly impaired behavioral functions, reduced the recovery index of compound muscle action potential (CMAP) amplitude, inhibited axonal regrowth, slowed M1 macrophage infiltration and shift to M2 phenotype, and delayed myelin debris clearance. Notably, all aforementioned results caused by KIF5b overexpression were alleviated by ropivacaine. Furthermore, we demonstrated that inhibition of Nav1.8 transport by A-803467 produced mitigating effects on the impairment of regenerative capacity induced by KIF5b overexpression similar to ropivacaine. These results suggest that ropivacaine promotes axonal regeneration at least partially by inhibiting KIF5b-mediated Nav1.8 forward transport.

The reduction of imidazole propionate induced by intermittent fasting promotes recovery of peripheral nerve injury by enhancing migration of Schwann cells

Peripheral nerve injury (PNI) accompanied with sensory and motor dysfunction has serious effect on the quality of life of patients. Intermittent fasting (IF), as a dietary pattern, has rarely been reported to influence imidazole propionate (ImP), a microbial metabolite, in vivo. To date, the link between ImP and PNI is unknown. This study aimed to explore the impact of ImP on the recovery after PNI and determine whether IF could reduce the concentration of ImP in vivo. Sciatic nerve injury rat model and RSC96 cells were utilized with 16s RNA seq, HE staining, CCK-8 assay, Western blot (WB), Transmission electron microscopy (TEM), immunofluorescence, transwell and scratch wound healing assays as read outs. WB, TEM, transwell and wound healing assay showed an inhibitory effect of ImP on autophagy and migration of Schwann cells. This negative effect on migration was reversed by rapamycin. Detection of p-Erk and p-mTOR confirmed that the MAPK/Erk/mTOR pathway was involved in this process. In vivo, IF changed the composition of gut microbiome, including bacteria related to ImP production and reduced the concentration of ImP in serum. In sum, IF influenced the composition of gut microbiome and reduced the concentration of ImP in vivo. The reduction of ImP promoted migration of SCs through enhancing autophagy which involved MAPK/Erk/mTOR pathway.

Exogenous NT-3 Promotes Phenotype Switch of Resident Macrophages and Improves Sciatic Nerve Injury through AMPK/NF-κB Signaling Pathway.

Neurotrophin-3 (NT-3) is an important family of neurotrophic factors with extensive neurotrophic activity, which can maintain the survival and regeneration of nerve cells. However, the mechanism of NT-3 on macrophage phenotype transformation after sciatic nerve injury is not clear. In this study, we constructed a scientific nerve compression injury animal model and administered different doses of NT-3 treatment through osmotic minipump. 7 days after surgery, we collected sciatic nerve tissue and observed the distribution of macrophage phenotype through iNOS and CD206 immunofluorescence. During the experiment, regular postoperative observations were conducted on rats. After the experiment, sciatic nerve tissue was collected for HE staining, myelin staining, immunofluorescence staining, and Western blot analysis. To verify the role of the AMPK/NF-κB pathway, we applied the AMPK inhibitor Compound C and the NF-κB inhibitor BAY11-7082 to repeat the above experiment. Our experimental results reveal that NT-3 promotes sciatic nerve injury repair and polarization of M2 macrophage phenotype, promotes AMPK activation, and inhibits NF-κB activation. The repair effect of high concentration NT-3 on sciatic nerve injury is significantly enhanced compared to low concentration. Compound C administration can weaken the effect of NT-3, while BAY 11-7082 can enhance the effect of NT-3. In short, NT-3 significantly improves sciatic nerve injury in rats, promotes sciatic nerve function repair, accelerates M2 macrophage phenotype polarization, and improves neuroinflammatory response. The protective effects of NT-3 mentioned above are partially related to the AMPK/NF-κB signal axis.

Repetitive magnetic stimulation prevents dorsal root ganglion neuron death and enhances nerve regeneration in a sciatic nerve injury rat model

Peripheral nerve injury (PNI) often leads to retrograde cell death in the spinal cord and dorsal root ganglia (DRG), hindering nerve regeneration and functional recovery. Repetitive magnetic stimulation (rMS) promotes nerve regeneration following PNI. Therefore, this study aimed to investigate the effects of rMS on post-injury neuronal death and nerve regeneration. Seventy-two rats underwent autologous sciatic nerve grafting and were divided into two groups: the rMS group, which received rMS and the control (CON) group, which received no treatment. Motor neuron, DRG neuron, and caspase-3 positive DRG neuron counts, as well as DRG mRNA expression analyses, were conducted at 1-, 4-, and 8-weeks post-injury. Functional and axon regeneration analyses were performed at 8-weeks post-injury. The CON group demonstrated a decreased DRG neuron count starting from 1 week post-injury, whereas the rMS group exhibited significantly higher DRG neuron counts at 1- and 4-weeks post-injury. At 8-weeks post-injury, the rMS group demonstrated a significantly greater myelinated nerve fiber density in autografted nerves. Furthermore, functional analysis showed significant improvements in latency and toe angle in the rMS group. Overall, these results suggest that rMS can prevent DRG neuron death and enhance nerve regeneration and motor function recovery after PNI.

Exercise as a promising alternative for sciatic nerve injury pain relief: a meta-analysis.

The efficacy of drug therapies in managing neuropathic pain is constrained by their limited effectiveness and potential for adverse effects. In contrast, exercise has emerged as a promising alternative for pain relief. In this study, we conducted a systematic evaluation of the therapeutic impact of exercise on neuropathic pain resulting from sciatic nerve injury in rodent models. The PubMed, Embase, and Web of Science databases were retrieved before April 2024. A series of studies regarding the effect of treadmill, swimming, wheel and other exercises on neuropathic pain induced by sciatic nerve injury in rats and mice were collected. Using predefined inclusion criteria, two researchers independently performed literature screening, data extraction, and methodological quality assessment utilizing SYRCLE's risk of bias tool for animal studies. Statistical analysis was conducted using RevMan 5.3 and STATA 12.0 analysis software. A total of 12 relevant academic sources were included in the analysis of controlled animal studies, with 133 rodents in the exercise group and 135 rodents in the sedentary group. The meta-analysis revealed that exercise was associated with a significant increase in paw withdrawal mechanical threshold [Standard Mean Difference (SMD) = 0.84, 95% confidence interval (CI): 0.28-1.40, p = 0.003] and paw withdrawal thermal latency (SMD = 1.54, 95%CI: 0.93-2.15, p < 0.0001) in rats and mice with sciatic nerve injury. Subgroup analyses were conducted to evaluate the impact of exercise duration on heterogeneity. The results showed that postoperative exercise duration ≤3 weeks could significantly elevate paw withdrawal mechanical threshold (SMD = 1.04, 95% CI: 0.62-1.46, p < 0.00001). Postoperative exercise duration ≤4 weeks could significantly improve paw withdrawal thermal latency (SMD = 1.93, 95% CI:1.19-2.67, p < 0.00001). Exercise represents an effective method for improving mechanical and thermal hypersensitivity resulting from sciatic nerve injury in rodents. Factors such as pain models, the initiation of exercise, the type of exercise, and the species of rodent do not significantly impact the development of exercise-induced hypoalgesia. However, the duration of postoperative exercise plays a crucial role in the onset of exercise-induced hypoalgesia.

Nerve Regeneration Through Differentiation of Endometrial-Derived Mesenchymal Stem Cells into Nerve-Like Cells Using Polyacrylonitrile/Chitosan Conduit and Berberine in a Rat Sciatic Nerve Injury Model.

Nervous injuries are common in humans. One of the most advanced treatment methods is neural tissue engineering. This research aims to utilize nerve-like cells (NLCs) derived from endometrial mesenchymal stem cells (EnMSCs) on a polyacrylonitrile/chitosan (PAN/CS) scaffold, along with berberine, for the reconstruction of a rat sciatic nerve injury model. In this experimental study, EnMSCs were obtained through enzymatic digestion and identified using flow cytometry and their differentiation into adipocyte and osteoblast. PAN nanofiber scaffolds were produced through electrospinning, and EnMSCs were neurally differentiated on these scaffolds for grafting into an animal model. The expression of Nestin, Map-2, Tuj-1, and NF genes in NLCs was confirmed through RT-PCR and immunocytochemistry. Twenty-five adult male rats were used in this study, divided into 5 groups: (1) Scaffold/Cells/Berberine, (2) Scaffold/Cells, (3) Scaffold, (4) Berberine, and (5) Control. The animals were maintained for 8 weeks, and their sciatic nerve function (SFI) was assessed. Additionally, histological examinations were performed using hematoxylin/eosin, luxol fast blue staining, and immunohistochemistry. According to the results, extraction, identification, and differentiation of EnMSCs and fabrication of PAN conduit and its transplantation were successfully performed. The best behavioral performance and histology were observed in the Scaffold/Cells/Berberine group. The SFI test results were -24.08 for the Scaffold/Cells/Berberine group and -39.27 for the control group. The nerve diameter in these two groups was 591 µm and 80 µm, respectively, and the percentage of new nerve formation was 18.5% in the Scaffold/Cells/Berberine group and 0.2% in the control group. The immunohistochemistry results demonstrated that the intensity of the green color was higher in the groups with cells compared to the groups without cells. Furthermore, in the luxol staining results, all groups showed a significant improvement compared to the control group. In the Scaffold/Cells/Berberine group, fibers, and axons appeared denser, more organized, and displayed a higher intensity of blue staining. According to the results of this study, EnMSCs demonstrated efficient differentiation into NLCs. With the assistance of PAN/CS scaffolds and simultaneous administration of berberine, EnMSCs have the potential for nerve regeneration and recovery from sciatic nerve injury in the rat animal model.

Effects of N-acetylcysteine on sciatic nerve healing: A histopathological, functional, and biochemical study of the rat sciatic nerve.

This study aims to evaluate the histopathological, biochemical, and functional effects of N-acetylcysteine (NAC), which has antioxidant, anti-inflammatory, and cytoprotective activity, on nerve regeneration in rats with sciatic nerve crush (axonotmesis) injury. This study used 16 male Wistar rats, which were divided into treatment and control groups. A standard axonotmesis-type surgical injury was induced in the left sciatic nerves of all rats. The treatment group was given 300 mg/kg of intraperitoneal NAC once a day, whereas the control group received an equal volume of saline solution. After conducting gait analyses, the sciatic functional index (SFI) was used for functional assessment. After gait analysis, all animals were euthanized. Blood samples were examined biochemically. The left sciatic nerves and left triceps surae muscles were examined histopathologically. Histopathologically, the thickness of the perineurium, axonal degeneration, axonolysis, edema, inflammation, muscle atrophy, and muscle degeneration were all significantly lower in the treatment group (p<0.05). Functionally, SFI-1, SFI-2, and SFI-3 were significantly higher in the treatment group (p<0.05). Biochemically, while the native thiol level and native thiol/total thiol ratio were significantly higher in the treatment group (p<0.003), the disulfide/total thiol ratio was significantly higher in the control group (p<0.005). Significant correlations were found between six of the seven gait parameters and the histopathological findings (p<0.05). Our study results suggest that NAC may contribute positively to the histopathological and functional recovery of sciatic nerve injury in rats. Furthermore, NAC may have an antioxidant effect on thiol-disulfide homeostasis at a biochemical level. We believe that NAC has a stimulatory effect on healing following nerve injuries.

BDNF-loaded chitosan-based mimetic mussel polymer conduits for repair of peripheral nerve injury.

Care for patients with peripheral nerve injury is multifaceted, as traditional methods are not devoid of limitations. Although the utilization of neural conduits shows promise as a therapeutic modality for peripheral nerve injury, its efficacy as a standalone intervention is limited. Hence, there is a pressing need to investigate a composite multifunctional neural conduit as an alternative treatment for peripheral nerve injury. In this study, a BDNF-loaded chitosan-based mimetic mussel polymer conduit was prepared. Its unique adhesion characteristics allow it to be suture-free, improve the microenvironment of the injury site, and have good antibacterial properties. Researchers utilized a rat sciatic nerve injury model to evaluate the progression of nerve regeneration at the 12-week postoperative stage. The findings of this study indicate that the chitosan-based mimetic mussel polymer conduit loaded with BDNF had a substantial positive effect on myelination and axon outgrowth. The observed impact demonstrated a favorable outcome in terms of sciatic nerve regeneration and subsequent functional restoration in rats with a 15-mm gap. Hence, this approach is promising for nerve tissue regeneration during peripheral nerve injury.

Transplantation of Neural Progenitor Cells Derived from Stem Cells from Apical Papilla Through Small-Molecule Induction in a Rat Model of Sciatic Nerve Injury

Background:Stem cell-based transplantation therapy holds promise for peripheral nerve injury treatment, but adult availability is limited. A cell culture protocol utilizing a small-molecule cocktail effectively reprogrammed stem cells from apical papilla (SCAPs) into neural progenitor cells, subsequently differentiating into neuron-like cells. This study aims to evaluate neural-induced SCAPs, with and without small-molecule cocktail, for sciatic nerve repair potential.Methods:A scaffold-free cell sheet technique was used to construct a three-dimensional cell sheet. Subsequently, this cell sheet was carefully rolled into a tube and seamlessly inserted into a collagen conduit, which was then transplanted into a 5 mm sciatic nerve injury rat model. Functional sciatic nerve regeneration was evaluated via toe spread test, walking track analysis and gastrocnemius muscle weight. Additionally, degree of sciatic nerve regeneration was determined based on total amount of myelinated fibers.Results:Small-molecule cocktail induced SCAPs enhanced motor function recovery, evident in improved sciatic function index and gastrocnemius muscle retention. We also observed better host myelinated fiber retention than undifferentiated SCAPs or neural-induced SCAPs without small-molecule cocktail. However, clusters of neuron-like cell bodies (surrounded by sparse myelinated fibers) were found in all cell sheet-implanted groups in the implantation region. This suggests that while the implanted cells likely survived transplantation, integration was poor and would likely hinder long-term recovery by occupying the space needed for host nerve fibers to project through.Conclusion:Neural-induced SCAPs with small-molecule cocktail demonstrated promising benefits for nerve repair; further research is needed to improve its integration and optimize its potential for long-term recovery.

Biocompatible 3D-Printed Devices With Adipose Stem Cells in the Regenerative Process of Sciatic Nerve Lesions in Rodent Models: An Experimental Study.

Peripheral nerve injuries are a significant clinical challenge. The rat sciatic nerve serves as an ideal model for studying nerve regeneration. Extensive research has been conducted to unravel the intricate mechanisms involved in peripheral nerve regeneration, aiming to develop effective therapeutic strategies for nerve injury patients. Research including different types of materials that can be used as nerve guides like synthetic polymershave been investigated for their biocompatibility and molding properties. Among multiple stem cell types, adipose-derived stem cells (ASCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), and induced pluripotent stem cells (iPSCs) have shown neuroprotective and regenerative important properties. The purposes of our study were to develop a protocol for rat sciatic nerve injury treated with 3D-printed guide and adipose stem cells to investigate nerve regeneration through histologic examination and biomechanical characteristics of muscular tissue. We use 20 (100%) male Wistar rats, measuring between 350 g ± 35 g, whounderwent complete transection of the right sciatic nerve, resulting in a 1 cm defect. The group was separated into three subgroups: the first subgroup (n = 8) was treated with a 3D-printed guide with adiposestem cells, the second subgroup (n = 8) was treated with a 3D-printed guide without adiposestem cells, and the third subgroup (n = 4) was the control group. At four, eight, and 12 weeks, we measured with ultrasonography the grade of muscular atrophy. At 12 weeks, we harvested the sciatic nerve and performed a histological examination and mechanical investigation of the tibialis anterior muscle. On the examined specimen of the first subgroup, cross-sectioned nerve structures were present, surrounded by a mature fibro-adipose connective tissue, with blood vessels. In the second subgroup, no nerve structure was observed on the examined sections, but in the polymorphic inflammatory infiltrate and control group, no signs of regeneration were found. The present study shows a promising potential when utilizing adipose stem cell-based therapies for promoting peripheral nerve regeneration following large (>1 cm) nerve defects knowing that at this size, regeneration is impossible with known treatments.

Acute Nerve Pedicle Transfer after Transection Prevents Neuroma Formation and Demonstrates Potential for Reinnervation in a Rat Sciatic Nerve Injury Model

Acute Nerve Pedicle Transfer after Transection Prevents Neuroma Formation and Demonstrates Potential for Reinnervation in a Rat Sciatic Nerve Injury Model

Investigation of the effectiveness of atmospheric pressure cold plasma on sciatic nerve injury in rats.

The aim of this study was to evaluate the efficacy of atmospheric pressure cold plasma jet and plasma activated medium (PAM) on sciatic nerve injury (SNI). Rats were divided into 6 groups (n = 10); group 1 (Sham), group 2 (SNI), group 3 (SNI + Atmospheric pressure cold plasma jet 5 min), group 4 (SNI + Atmospheric pressure cold plasma jet 10 min), group 5 (SNI + PAM 5 min), group 6 (SNI + PAM 10 min). On the 1st, 8th, 15th, 22nd days of the study, atmospheric pressure cold plasma jet was applied to rats in groups 3 and 4, and PAM was applied to rats in groups 5 and 6. Hot plate test was applied to all rats on the same days. On day 28, the experiment was terminated and sciatic nerve tissues were removed for histopathologic evaluations. According to the 4-week average of the hot plate tests, a significant relationship was found between group 2 and group 4 and group 6 (p < 0.05). When evaluated within each week, significant differences were found between group 2 and group 4 in week 1, between group 2 and group 5 and group 6 in week 2, between group 2 and group 4 in week 3, and between group 2 and group 4 and group 6 in week 4 (p < 0.05). As a result of histopathologic analysis, except for the control group, the other groups had similar characteristics in terms of axonal degeneration, periaxonal swelling and axon density. As a result of our study, we found that plasma application showed an improvement in the duration of the hot plate test, but did not show any improvement histopathologically.

DNA origami scaffold promoting nerve guidance and regeneration.

Self-assembly of biological elements into biomimetic cargo carriers for targeting and delivery is a promising approach. However, it still holds practical challenges. We developed a functionalization approach of DNA origami (DO) nanostructures with neuronal growth factor (NGF) for manipulating neuronal systems. NGF bioactivity and its interactions with the neuronal system were demonstrated in vitro and in vivo models. The DO elements fabricated by molecular self-assembly have manipulated the surrounding environment through static spatially and temporally controlled presentation of ligands to the cell surface receptors. Our data showed effective bioactivity in differentiating PC12 cells in vitro. Furthermore, the DNA origami NGF (DON) affected the growth directionality and spatial capabilities of dorsal root ganglion neurons in culture by introducing a chemotaxis effect along a gradient of functionalized DO structures. Finally, we showed that these elements provide enhanced axonal regeneration in a rat sciatic nerve injury model in vivo. This study is a proof of principle for the functionality of DO in neuronal manipulation and regeneration. The approach proposed here, of an engineered platform formed out of programmable nanoscale elements constructed of DO, could be extended beyond the nervous system and revolutionize the fields of regenerative medicine, tissue engineering, and cell biology.

Comparative evaluation of bone marrow and dental pulp mesenchymal stem cells for motor functional recovery in rat sciatic nerve injury.

This study delves into the impact of mesenchymal stem cells derived from bone marrow (BM-MSCs) and those sourced from dental pulp (DP-MSCs) on the recovery of motor function and morphological aspects of the rat's sciatic nerve after crush injuries. The findings highlight that the groups treated with BM-MSCs, DP-MSCs or a combination of both (BM + DP-MSCs) displayed enhanced sciatic functional index values when juxtaposed with the sham group. This points to bettered motor functionalities. A deeper morphological analysis showed that all the groups had retained perineurium structure and fascicular arrangement. Notably, the sham and BM-MSCs groups had very few inconsistencies. All groups showed standard vascular density. Remarkably, the combined treatment group (BM + DP-MSCs) presented diminished oedema and a lower count of inflammatory cells. Through immunohistochemical methods, the presence of S100 expression was noted in the groups that underwent treatment. In summation, the study suggests that both BM-MSCs and DP-MSCs, whether used singly or in combination, can significantly aid in motor function restoration and morphological enhancements. An interesting observation from our research and earlier studies is that stem cells from dental pulp, which are sourced with less discomfort from milk and wisdom teeth, show a heightened propensity to evolve into nerve cells. This is in contrast to the more uncomfortably acquired BM-MSCs.

Dental Pulp Stem Cell-Derived Exosomes Promote Sciatic Nerve Regeneration via Optimizing Schwann Cell Function.

Repair strategies for injured peripheral nerve have achieved great progresses in recent years. However, the clinical outcomes remain unsatisfactory. Recent studies have found that exosomes secreted by dental pulp stem cells (DPSC-exos) have great potential for applications in nerve repair. In this study, we evaluated the effects of human DPSC-exos on improving peripheral nerve regeneration. Initially, we established a coculture system between DPSCs and Schwann cells (SCs) in vitro to assess the effect of DPSC-exos on the activity of embryonic dorsal root ganglion neurons (DRGs) growth in SCs. We extracted and labeled human DPSC-exos, which were subsequently utilized in uptake experiments in DRGs and SCs. Subsequently, we established a rat sciatic nerve injury model to evaluate the therapeutic potential of DPSC-exos in repairing sciatic nerve damage. Our findings revealed that DPSC-exos significantly promoted neurite elongation by enhancing the proliferation, migration, and secretion of neurotrophic factors by SCs. In vivo, DPSC-exos administration significantly improved the walking behavior, axon regeneration, and myelination in rats with sciatic nerve injuries. Our study underscores the vast potential of DPSC-exos as a therapeutic tool for tissue-engineered nerve construction.

Effects of tetramethylpyrazine on pharmacokinetics in plasma and brain dialysate and neuropathic pain in rat model of spared sciatic nerve injury

This study aims to explore the effects of tetramethylpyrazine(TMP) on pharmacokinetics in plasma and brain dialysate and neuropathic pain in the rat model of partial sciatic nerve injury(SNI), and to investigate the correlation between the analgesic effect of TMP and its concentrations in the plasma and brain dialysate. Male SD rats were randomized into Sham, SNI, and SNI+TMP groups. Mechanical stimulation with von frey filaments and cold spray method were employed to evaluate the mechanical sensitivity and cold sensitivity of rats. Another two groups, Sham+TMP and SNI+TMP, were used to intubate the common jugular vein and implant microdialysis probes into the anterior cingulate gyrus(ACC), respectively.After intraperitoneal injection of TMP at a dose of 80 mg·kg~(-1), automatic blood collection and intracerebral microdialysis(perfusion rate of 1 μL·min~(-1)) systems were used to collect the blood and brain dialysate for 24 h. HSS T3 C_(18) reversed-phase chromatographic column(2.1 mm×50 mm, 2.5 μm) was used for liquid chromatographic separation. Gradient elution was carried out with the mobile phase of methanol-water(containing 0.005% formic acid) at a flow rate of 0.25 mL·min~(-1). Electrospray ion source was used for mass spectrometry, and the scanning mode was multi-reaction monitoring under the positive ion mode. The ion pairs for quantitative analysis were TMP m/z 137/122 and aspirin m/z 179/137, respectively. DAS 2.11 was used to calculate the pharmacokinetic parameters. The optimal time of TMP to exert the analgesia effect and inhibit cold pain sensitivity was 60 min after treatment. The TMP in the plasma and brain dialysate of SNI rats showed the T_(max) of 15 min and 30 min, the C_(max) of(2 866.43±135.39) and(1 462.14±197.38) μg·L~(-1), the AUC_(0-t) of(241 463.30±28 070.31) and(213 115.62±32 570.07) μg·min·L~(-1), the MRT_(0-t) of(353.13±47.73) and(172.16±12.72) min, and the CL_Z of 0.73 and 0.36 L·min·kg~(-1), respectively. The analgesic effect of TMP had a significant correlation with the blood drug concentration in the ACC, which indicated that this method was suitable for the detection of TMP in rat plasma and brain dialysate. The method is accurate, reliable, and sensitive and can realize the important value of the application of correlation analysis theory of &quot;automatic blood collection-microdialysis/PK-PD&quot; in the research on neuropathic pain.

Leveraging Oriented Lateral Walls of Nerve Guidance Conduit with Core-Shell MWCNTs Fibers for Peripheral Nerve Regeneration.

Peripheral nerve regeneration and functional recovery rely on the chemical, physical, and structural properties of nerve guidance conduits (NGCs). However, the limited support for long-distance nerve regeneration and axonal guidance has hindered the widespread use of NGCs. This study introduces a novel nerve guidance conduit with oriented lateral walls, incorporating multi-walled carbon nanotubes (MWCNTs) within core-shell fibers prepared in a single step using a modified electrohydrodynamic (EHD) printing technique to promote peripheral nerve regeneration. The structured conduit demonstrated exceptional stability, mechanical properties, and biocompatibility, significantly enhancing the functionality of NGCs. In vitro cell studies revealed that RSC96 cells adhered and proliferated effectively along the oriented fibers, demonstrating a favorable response to the distinctive architectures and properties. Subsequently, a rat sciatic nerve injury model demonstrated effective efficacy in promoting peripheral nerve regeneration and functional recovery. Tissue analysis and functional testing highlighted the significant impact of MWCNT concentration in enhancing peripheral nerve regeneration and confirming well-matured aligned axonal growth, muscle recovery, and higher densities of myelinated axons. These findings demonstrate the potential of oriented lateral architectures with coaxial MWCNT fibers as a promising approach to support long-distance regeneration and encourage directional nerve growth for peripheral nerve repair in clinical applications.

Study on the Role and Mechanism of Exosomes Derived from Dental Pulp Stem Cells in Promoting Regeneration of Myelin Sheath in Rats with Sciatic Nerve Injury.

The prognosis of peripheral nerve injury (PNI) is usually poor, and currently, there is no effective treatment for PNI. Studies have shown that exosomes derived from mesenchymal stem cells could promote nerve regeneration by optimizing the function of endogenous Schwann cells (SCs), while the mechanism is unclear. Autophagy, a highly conserved intracellular catabolic process responsible for maintaining cellular homeostasis, has been proved to be involved in the regulation of nerve repair after injury. We explored the effect of exosomes derived from dental pulp stem cells (DPSC-Exos) on the regeneration of myelin sheath in rats with sciatic nerve injury (SNI). In vitro and in vivo experiments were performed to clarify whether the effect of DPSC-Exos is associated with autophagy of SCs and to reveal the mechanism at the molecular level. Our results showed that the SCs of SNI rats exhibited the obvious autophagic characteristics, and the increase of P53 expression was an internal factor of autophagy. Our mechanism research indicated that DPSC-Exos could deliver miR-122-5p from DPSCs into SCs and suppressed the rapamycin (RAPA)-induced autophagy in SCs by inhibiting P53 expression. Rescue experiments showed that both the use of GW4869 and overexpression of exogenous P53 in SCs could reverse the inhibitory effect of DPSCs on the autophagy in SCs from co-culture system. In short, our study indicated that DPSC-Exos could promote the regeneration of the myelin sheath through suppressing the autophagy in SCs caused by PNI via miR-122-5p/P53 pathway; this provides researchers with another option for precise repair of PNI.