Rat Sciatic Nerve Research Articles

Cimifugin Alleviates Chronic Constriction Injury of the Sciatic Nerve by Suppressing Inflammatory Response and Schwann Cell Apoptosis.

Inflammation and Schwann cell apoptosis play critical roles in neuropathic pain after sciatic nerve injury. This study aimed to explore the function and mechanism of cimifugin in lipopolysaccharide (LPS)-stimulated rat Schwann cells and sciatic nerves of rats treated with chronic constriction injury (CCI). Thermal, mechanical and cold hyperalgesia of rats in response to cimifugin or mecobalamin (the positive drug control) treatment were evaluated through behavioral tests. H&E staining of sciatic nerves was performed for pathological observation. ELISA was conducted to assess concentrations of inflammatory cytokines in rat serum and sciatic nerves. The intensity of S100β in sciatic nerves was determined using immunohistochemistry. Flow cytometry analysis was conducted for detection of Schwann cell apoptosis. RT-qPCR was performed to measure mRNA levels of inflammatory factors in Schwann cells. Immunofluorescence staining was performed to detect cellular p65/NF-κB activity. Western blotting was performed to quantify protein levels of apoptotic markers and factors associated with the NF-κB and MAPK pathways in rat nerves and Schwann cells. As shown by experimental data, cimifugin mitigated thermal, mechanical and cold hyperalgesia of CCI rats. Cimifugin repressed inflammatory cell infiltration, reduced proinflammatory cytokine levels while increasing anti-inflammatory factor (IL-10) level in serum or sciatic nerves of CCI rats. Cimifugin enhanced S100β expression and downregulated apoptotic markers in vivo. The anti-inflammatory and anti-apoptotic properties of cimifugin were verified in the LPS-stimulated Schwann cells. Moreover, cimifugin suppressed nuclear translocation of p65 NF-κB in vitro and repressed the phosphorylation of IκB, p65 NF-κB, p38 MAPK, ERK1/2, as well as JNK in CCI rats. In conclusion, cimifugin alleviates neuropathic pain after sciatica by suppressing inflammatory response and Schwann cell apoptosis via inactivation of NF-κB and MAPK pathways.

AGMATINE ADMINISTRATION ALLEVIATES NERVE DAMAGE AND IMPROVES NERVE FUNCTION IN METHOTREXATE INDUCED PERIPHERAL NEUROPATHY IN RATS

Objective: Chemotherapeutic agents can produce neurodegenerative changes. This study was conducted to assess the therapeutic potential of agmatine, a neuromodulator, on methotrexate induced neurodegeneration in sciatic nerve. Materials and Methods: 40 male Wistar albino rats were assigned into four groups at random as control, methotrexate, agmatine and methotrexate-agmatine. Methotrexate was injected intraperitoneally at a 37.5 mg/kg/week dose for 3 weeks. Afterwards, agmatine was administered intraperitoneally twice a day at a 40 mg/kg dose for 7 days. Sciatic functional index, nociceptive pain perception and behavioral changes were analyzed every week. Nerve conduction velocity was evaluated. Apoptotic activity and mitophagy, histopathological changes in sciatic nerves were examined. Results: Methotrexate administration resulted in a prolonged escape time to the platform and decreased the time spent in the quadrant in the water maze test; elevated nociceptive latencies; decreased the number of frames passed in the open field test; reduced sciatic NCV and SFI score. Besides, methotrexate administration caused a reduction in myelin thickness and axon diameter in sciatic nerve and a more intense glial fibrillary acidic protein immunoreactivity. Methotrexate administration triggered an increase in the Bax/Bcl-2 protein expression ratio without changing the expression level of Parkin, indicating a slight apoptotic activation. agmatine administration improved methotrexate induced changes in behavioral performances, nociceptive pain perception, nerve conduction, SFI scores and histopathological changes. Conclusion: Agmatine has been demonstrated to possess a therapeutic potential in methotrexate induced degeneration and peripheral neuropathy in the rat sciatic nerve.

Fabrication of Anatomically Equivalent Pectin-Based Multifilament Nerve Conduits.

Reuniting denuded nerve ends after a long segmental peripheral nerve defect is challenging due to delayed axonal regeneration and incomplete, nonspecific reinnervation, as conventional hollow nerve guides fail to ensure proper fascicular complementation and obstruct axonal guidance across the defects. This study focuses on fabricating multifilament conduits using a plant-derived anionic polysaccharide, pectin, where the abundant availability of carboxylate (COO-) functional groups in pectin facilitates instantaneous sol-gel transition upon interaction with divalent cations. Despite their advantages, pectin hydrogels encounter structural instability under physiological conditions. Hence, pectin is conjugated with light-sensitive methacrylate residues (49.8% methacrylation) to overcome these issues, enabling the fabrication of dual cross-linked multifilament nerve conduits through an ionic interaction-driven, template-free 3D wet writing process, followed by photo-cross-linking at 525 nm. The anatomical equivalence including peri-, epi-, and endoneurium structures of the customized multifilament conduits was confirmed through scanning electron micrographs and micro-CT analysis of rat and goat sciatic nerve tissues. Furthermore, the fabricated multifilament nerve conduits demonstrated cytocompatibility and promoted the expression of neuron-specific intermediate filament protein (NF-200) in PC12 cells and neurite outgrowth of 16.90 ± 1.82 μm on day 14. Micro-CT imaging of an anastomosed native goat sciatic nerve with an 8-filament conduit demonstrated precise fascicular complementation in an ex vivo interpositional goat model. This approach not only eliminates the need for a suture-intensive ligation process but also highlights the customizability of multifilament conduits to meet patient- and injury-specific needs.

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.

Peripheral Nerve Injury After Deoxycholic Acid (ATX-101) Injection in an Experimental Rat Model.

Deoxycholic acid (ATX-101) is a drug administered by subcutaneous injection for local fat reduction. However, ATX-101 treatment has been reported to cause marginal mandibular nerve injury with noticeable functional deficits when targeting submental fat. As a cytolytic agent with some selectivity for adipocytes, ATX-101 may damage the lipid-rich myelin surrounding peripheral nerves. This study seeks to characterize the nerve injection injury from ATX-101 in an experimental rat model. Using a rat sciatic nerve injection model, intrafascicular and extrafascicular injections of deoxycholic acid (ATX-101) were compared to lidocaine (positive control) and saline (negative control). Nerves were harvested at a 2-week endpoint for histomorphometric analysis. Cross-sectional area of nerve injury was significantly increased by ATX-101 injection at 75±15% with intrafascicular ATX-101 (p<0.001), 41±21% with extrafascicular ATX-101 (p<0.01), and 38±20% with positive control lidocaine (p<0.01) compared to 7±13% with negative control saline. Demyelinating injury was a significant mechanism of injury in the affected nerve fibers compared to uninjured nerve fibers (p<0.04), but there was no difference in axon-to-myelin area ratio between the lidocaine and ATX-101 cohorts. After two weeks, Wallerian degeneration was evident with only small regenerating nerve fibers present in the ATX-101-injured groups compared to saline (2.54±0.26um vs 5.03±0.44um, p<0.001) in average width. Deoxycholic acid (ATX-101) is capable of extensive nerve injury in rats. The mechanism of action for ATX-101 does not preferentially target myelin more than other common neurotoxic agents. Appropriate knowledge of surgical anatomy and injection technique is necessary for any practitioners providing ATX-101 injections.

Establishment of a Magnetically Controlled Scalable Nerve Injury Model.

Animal models of peripheral nerve injury (PNI) serve as the fundamental basis for the investigations of nerve injury, regeneration, and neuropathic pain. The injury properties of such models, including the intensity and duration, significantly influence the subsequent pathological changes, pain development, and therapeutic efficacy. However, precise control over the intensity and duration of nerve injury remains challenging within existing animal models, thereby impeding accurate and comparative assessments of relevant cases. Here, a new model that provides quantitative and off-body controllable injury properties via a magnetically controlled clamp, is presented. The clamp can be implanted onto the rat sciatic nerve and exert varying degrees of compression under the control of an external magnetic field. It is demonstrated that this model can accurately simulate various degrees of pathology of human patients by adjusting the magnetic control and reveal specific pathological changes resulting from intensity heterogeneity that are challenging to detect previously. The controllability and quantifiability of this model may significantly reduce the uncertainty of central response and inter-experimenter variability, facilitating precise investigations into nerve injury, regeneration, and pain mechanisms.

Gap junction protein connexin 43 and its distribution in damaged nerve cells

BACKGROUND: Connexins, particularly connexin 43, form gap junctions that mediate neuron-glial communication. To date, the expression of connexin 43 in phenotypically distinct neurolemmocytes, in particular non-myelinating (Remak cells) and repair Schwann cells, has not been studied. AIM: To determine the presence of connexin 43 in Schwann cells of the rat sciatic nerve under normal conditions and after mechanical damage by applying a ligature. MATERIALS AND METHODS: The study was carried out on Wistar rats (n = 10). In experimental rats, the sciatic nerve was damaged by applying a ligature (40 s). 7 days after surgery, sciatic nerve segments were isolated for subsequent immunohistochemical study using antibodies to connexin 43 and glial fibrillary acidic protein (GFAP). In the control group rats, segments of intact sciatic nerves were isolated in a similar way. RESULTS: It has been shown that in the endoneurium of the intact rat sciatic nerve there are no cells expressing connexin 43. It was found that 7 days after injury, a large number of connexin-43-immunopositive cells of irregular shape with several processes were identified in the endoneurium of the damaged nerve. There was a lack of expression of connexin 43 in GFAP-containing Schwann cells. CONCLUSIONS: It can be stated that nerve damage leads to active synthesis of the studied protein by endoneurium cells; however, the origin of the cells expressing connexin 43 remains to be elucidated.

Identification of spread after deliberate intraneural injection in five mammalian species

IntroductionThis research endeavors to investigate the phenomenon of intraneural spread across distinct locations: subcircumneurium, extrafascicular intraneural, intrafascicular intraneural, and intraperineurium after deliberate intraneural injections across five mammalian species. The study...

Decellularized Biohybrid Nerve Promotes Motor Axon Projections.

Developing nerve grafts with intact mesostructures, superior conductivity, minimal immunogenicity, and improved tissue integration is essential for the treatment and restoration of neurological dysfunctions. A key factor is promoting directed axon growth into the grafts. To achieve this, biohybrid nerves are developed using decellularized rat sciatic nerve modified by in situ polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). Nine biohybrid nerves are compared with varying polymerization conditions and cycles, selecting the best candidate through material characterization. These results show that a 1:1 ratio of FeCl3 oxidant to ethylenedioxythiophene (EDOT) monomer, cycled twice, provides superior conductivity (>0.2mScm-1), mechanical alignment, intact mesostructures, and high compatibility with cells and blood. To test the biohybrid nerve's effectiveness in promoting motor axon growth, human Spinal Cord Spheroids (hSCSs) derived from HUES 3 Hb9:GFP cells are used, with motor axons labeled with green fluorescent protein (GFP). Seeding hSCS onto one end of the conduit allows motor axon outgrowth into the biohybrid nerve. The construct effectively promotes directed motor axon growth, which improves significantly after seeding the grafts with Schwann cells. This study presents a promising approach for reconstructing axonal tracts in humans.

In silico model for automated calculation of functional metrics in animal models of peripheral nerve injury repair

The rat sciatic nerve model is commonly used to test novel therapies for nerve injury repair. The static sciatic index (SSI) is a useful metric for quantifying functional recovery, and involves comparing an operated paw versus a control paw using a weighted ratio between the toe spread and the internal toe spread. To calculate it, rats are placed in a transparent box, photos are taken from underneath and the toe distances measured manually. This is labour intensive and subject to human error due to the challenge of consistently taking photos, identifying digits and making manual measurements. Although several commercial kits have been developed to address this challenge, they have seen little dissemination due to cost. Here we develop a novel algorithm for automatic measurement of SSI metrics based on video data using casted U-Nets. The algorithm consists of three U-Nets, one to segment the hind paws and two for the two pairs of digits which input into the SSI calculation. A training intersection over union error of 60 % and 80 % was achieved for the back paws and for both digit segmentation U-Nets, respectfully. The algorithm was tested against video data from three separate experiments. Compared to manual measurements, the algorithm provides the same profile of recovery for every experiment but with a tighter standard deviation in the SSI measure. Through the open-source release of this algorithm, we aim to provide an inexpensive tool to more reliably quantify functional recovery metrics to the nerve repair research community.

Assessing tissue mechanical properties: Development of a custom-made tensile device and application on rodents sciatic nerves

The development of biomaterials such as synthetic scaffolds for peripheral nerve regeneration requires a precise knowledge of the mechanical properties of the nerve in physiological-like conditions. Mechanical properties (Young’s modulus, maximum stress and strain at break) for peripheral nerves are scarce and large discrepancies are observed in between reports. This is due in part to the absence of a robust testing device for nerves. To overcome this limitation, a custom-made tensile device (CMTD) has been built. To evaluate its reproducibility and accuracy, the imposed speed and distance over measured speed and distance was performed, followed by a validation using poly(dimethylsiloxane) (PDMS), a commercial polymer with established mechanical properties. Finally, the mechanical characterization of rodents (mice and rats) sciatic nerves using the CMTD was performed. Mouse and rat sciatic nerves Young’s modulus were 4.57 ± 2.04 and 19.2 ± 0.86 MPa respectively. Maximum stress was 1.26 ± 0.56 MPa for mice and 3.81 ± 1.84 MPa for rats. Strain at break was 53 ± 17% for mice and 32 ± 12% for rats. The number of axons per sciatic nerve was found to be twice higher for rats. Statistical analysis of the measured mechanical properties revealed no sex-related trends, for both mice and rats (except for mouse maximum stress with p=0.03). Histological evaluation of rat sciatic nerve corroborated these findings. By developing a robust CMTD to establish the key mechanical properties (Young’s modulus, maximum stress and strain at break) values for rodents sciatic nerves, our work represent an essential step toward the development of better synthetic scaffolds for peripheral nerve regeneration.

Multi-Channel Microscale Nerve Cuffs for Spatially Selective Neuromodulation.

Peripheral nerve modulation via electrical stimulation shows promise for treating several diseases, but current approaches lack selectivity, leading to side effects. Exploring selective neuromodulation with commercially available nerve cuffs is impractical due to their high cost and limited spatial resolution. While custom cuffs reported in the literature achieve high spatial resolutions, they require specialized microfabrication equipment and significant effort to produce even a single design. This inability to rapidly and cost-effectively prototype novel cuff designs impedes research into selective neuromodulation therapies in acute studies. To address this, we developed a reproducible method to easily create multi-channel epineural nerve cuffs for selective fascicular neuromodulation. Leveraging commercial flexible printed circuit (FPC) technology, we created cuffs with high spatial resolution (50 μm) and customizable parameters like electrode size, channel count, and cuff diameter. We designed cuffs to accommodate adult mouse or rat sciatic nerves (300-1500 μm diameter). We coated the electrodes with PEDOT:PSS to improve the charge injection capacity. We demonstrated selective neuromodulation in both rats and mice, achieving preferential activation of the tibialis anterior (TA) and lateral gastrocnemius (LG) muscles. Selectivity was confirmed through micro-computed tomography (μCT) and quantified through a selectivity index. These results demonstrate the potential of this fabrication method for enabling selective neuromodulation studies while significantly reducing production time and costs compared to traditional approaches.

A tacrolimus-eluting nerve guidance conduit enhances regeneration in acritical-sized peripheral nerve injury rat model.

Critical-sized peripheral nerve injuries pose a significant clinical challenge and lead to functional loss and disability. Current regeneration strategies, including autografts, synthetic nerve conduits, and biologic treatments, encounter challenges such as limited availability, donor site morbidity, suboptimal recovery, potential immune responses, and sustained stability and bioactivity. An obstacle in peripheral nerve regeneration is the immune response that can lead to inflammation and scarring that impede the regenerative process. Addressing both the immunological and regenerative needs is crucial for successful nerve recovery. Here, we introduce a novel biodegradable tacrolimus-eluting nerve guidance conduit engineered from a blend of poly (L-lactide-co-caprolactone) to facilitate peripheral nerve regeneration and report the testing of this conduit in 15-mm critical-sized gaps in the sciatic nerve of rats. The conduit's diffusion holes enable the local release of tacrolimus, a potent immunosuppressant with neuro-regenerative properties, directly into the injury site. A series of in vitro experiments were conducted to assess the ability of the conduit to maintain a controlled tacrolimus release profile that could promote neurite outgrowth. Subsequent in vivo assessments in rat models of sciatic nerve injury revealed significant enhancements in nerve regeneration, as evidenced by improved axonal growth and functional recovery compared to controls using placebo conduits. These findings indicate the synergistic effects of combining a biodegradable conduit with localized, sustained delivery of tacrolimus, suggesting a promising approach for treating peripheral nerve injuries. Further optimization of the design and long-term efficacy studies and clinical trials are needed before the potential for clinical translation in humans can be considered.

(+)-Catechin attenuates CCI-induced neuropathic pain in male rats by promoting the Nrf2 antioxidant pathway to inhibit ROS/TLR4/NF-κB-mediated activation of the NLRP3 inflammasome.

The objective of this study was to investigate the potential mechanisms by which (+)-catechin alleviates neuropathic pain. Thirty-two male Sprague-Dawley rats were divided into four groups: the sham group, the chronic constriction injury (CCI)group, the CCI+ ibuprofen group, and the CCI+ (+)-catechin group. CCI surgery induces thermal hyperalgesia in rats and (+)-catechin ameliorated CCI-induced thermal hyperalgesia and repaired damaged sciatic nerve in rats. CCI decreased SOD levels in male rat spinal cord dorsal horn and promoted MDA production, induced oxidative stress by increasing NOX4 levels and decreasing antioxidant enzyme HO-1 levels, and also increased protein levels of TLR4, p-NF-κB, NLRP3 inflammasome components, and IL-1β. In contrast, (+)-catechin reversed the above results. In i vitro experiments, (+)-catechin reduced the generation of reactive oxygen species (ROS) in GMI-R1 cells after LPS stimulation and attenuated the co-expression of IBA-1 and NLRP3. It also showed significant inhibition of the NF-κB and NLRP3 inflammatory pathways and activation of the Nrf2-mediated antioxidant system. Overall, these findings suggest that (+)-catechin inhibits the activation of the NLRP3 inflammasome through the triggering of the Nrf2-induced antioxidant system, the inhibition of the TLR4/NF-κB pathway, and the production of ROS to alleviate CCI-induced neuropathic pain in male rats.

Multilevel neurium-mimetic individualized graft via additive manufacturing for efficient tissue repair

Complicated peripheral nerve injuries or defects, especially at branching sites, remain a prominent clinical challenge after the application of different treatment strategies. Current nerve grafts fail to match the expected shape and size for delicate and precise branched nerve repair on a case-by-case basis, and there is a lack of geometrical and microscale regenerative navigation. In this study, we develop a sugar painting-inspired individualized multilevel epi-/peri-/endoneurium-mimetic device (SpinMed) to customize natural cues, featuring a selectively protective outer sheath and an instructive core, to support rapid vascular reconstruction and consequent efficient neurite extension along the defect area. The biomimetic perineurium dictates host-guest crosslinking in which new vessels secrete multimerin 1 binding to the fibroin filler surface as an anchor, contributing to the biological endoneurium that promotes Schwann cell homing and remyelination. SpinMed implantation into rat sciatic nerve defects yields a satisfactory outcome in terms of structural reconstruction, with sensory and locomotive function restoration. We further customize SpinMed grafts based on anatomy and digital imaging, achieving rapid repair of the nerve trunk and branches superior to that achieved by autografts and decellularized grafts in a specific beagle nerve defect model, with reliable biosafety. Overall, this intelligent art-inspired biomimetic design offers a facile way to customize sophisticated high-performance nerve grafts and holds great potential for application in translational regenerative medicine.

Anethole Prevents the Alterations Produced by Diabetes Mellitus in the Sciatic Nerve of Rats.

Anethole is a terpenoid with antioxidant, anti-inflammatory, and neuronal blockade effects, and the present work was undertaken to study the neuroprotective activity of anethole against diabetes mellitus (DM)-induced neuropathy. Streptozotocin-induced DM rats were used to investigate the effects of anethole treatment on morphological, electrophysiological, and biochemical alterations of the sciatic nerve (SN). Anethole partially prevented the mechanical hyposensitivity caused by DM and fully prevented the DM-induced decrease in the cross-sectional area of the SN. In relation to electrophysiological properties of SN fibers, DM reduced the frequency of occurrence of the 3rd component of the compound action potential (CAP) by 15%. It also significantly reduced the conduction velocity of the 1st and 2nd CAP components from 104.6 ± 3.47 and 39.8 ± 1.02 to 89.9 ± 3.03 and 35.4 ± 1.56 m/s, respectively, and increased the duration of the 2nd CAP component from 0.66 ± 0.04 to 0.82 ± 0.09 ms. DM also increases oxidative stress in the SN, altering values related to thiol, TBARS, SOD, and CAT activities. Anethole was capable of fully preventing all these DM electrophysiological and biochemical alterations in the nerve. Thus, the magnitude of the DM-induced neural effects seen in this work, and the prevention afforded by anethole treatment, place this compound in a very favorable position as a potential therapeutic agent for treating diabetic peripheral neuropathy.

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.

Efficacy of 3D printed anatomically equivalent thermoplastic polyurethane guide conduits in promoting the regeneration of critical-sized peripheral nerve defects.

Three-dimensional (3D) printing is an emerging tool for creating patient-specific tissue constructs analogous to the native tissue microarchitecture. In this study, anatomically equivalent 3D nerve conduits were developed using thermoplastic polyurethane (TPU) by combining reverse engineering and material extrusion (i.e., fused deposition modeling) technique. Printing parameters were optimized to fabricate nerve-equivalent TPU constructs. The TPU constructs printed with different infill densities supported the adhesion, proliferation, and gene expression of neuronal cells. Subcutaneous implantation of the TPU constructs for three months in rats showed neovascularization with negligible local tissue inflammatory reactions and was classified as a non-irritant biomaterial as per ISO 10993-6. To perform in vivo efficacy studies, nerve conduits equivalent to rat's sciatic nerve were fabricated and bridged in a 10 mm sciatic nerve transection model. After four months of implantation, the sensorimotor function and histological assessments revealed that the 3D printed TPU conduits promoted the regeneration in critical-sized peripheral nerve defects equivalent to autografts. ThisstudyprovedthatTPU-based 3D printed nerve guidance conduits can be created to replicate the complicated features ofnaturalnerves that can promote the regeneration of peripheral nerve defects and also show the potential to be extended to several other tissues for regenerative medicine applications.&#xD.

Augmentation of functional recovery via ROCK/PI3K/AKT pathway by Fasudil Hydrochloride in a rat sciatic nerve transection model

BackgroundsThe functional recovery after peripheral nerve injury remains unsatisfactory. This study aims to perform a comprehensive evaluation of the efficacy of Fasudil Hydrochloride at treating the sciatic nerve transection injury in rats and the mechanism involved. Materials and methodsIn animal experiments, 75 Sprague Dawley rats that underwent transection and repair of the right sciatic nerve were divided into a control, Fasudil, and Fas + LY group, receiving daily intraperitoneal injection of saline, Fasudil Hydrochloride (10 mg/kg), and Fasudil Hydrochloride plus LY294002 (5 mg/kg), respectively. At day 3 after surgery, the expression of ROCK2, p-PI3K, and p-AKT in L4-5 DRG and the lumbosacral enlargement was determined using Western blotting. At day 7 and 14, axon density in the distal stump was evaluated with immunostaining using the anti-Neurofilament-200 antibody. At day 30, retrograde tracing by injecting Fluoro-gold in the distal stump was performed. Three months after surgery, remyelination was analyzed with immostaining using the anti-MPZ antibody and the transmission electron microscope; Moreover, Motion-Evoked Potential, and recovery of sensorimotor functions was evaluated with a neuromonitor, Footprint, Hot Plate and Von Frey Filaments, respectively. Moveover, the Gastrocnemius muscles were weighed, and then underwent H＆E staining, and staining of the neuromuscular junction using α-Bungarotoxin to evaluate the extent of atrophy and degeneration of the endplates in the Gastrocnemius. In vitro, spinal motor neurons (SMNs) and dorsal root ganglia (DRG) were cultured to examine the impact of Fasudil Hydrochloride and LY294002 on the axon outgrowth. ResultsThree days after injury, the expression of ROCK2 increased significantly (P＜0.01), and Fasudil application significantly increased the expression of p-PI3K and p-AKT in L4-6 DRG and the lumbosacral enlargement (P < 0.05). At day 7 and 14 after surgery, a higher axon density could be observed in the Fasudil group(P < 0.05). At day 30 after surgery, a larger number of motor and sensory neurons absorbing Fluoro-gold could be observed in the Fasudil group (P < 0.01) Three months after surgery, a greater thickness of myelin sheath could be observed in the Fasudil group (P < 0.05). The electrophysiological test showed that a larger amplitude of motion-evoked potential could be triggered in the Fasudil group (P < 0.01). Behavioral tests showed that a higher sciatic function index and a lower threshold for reacting to heat and mechanical stimuli could be measured in the Fasudil group. (P < 0.01). The wet weight ratio of the Gastrocnemius muscles and the area of the cross section of its myofibrils were greater in the Fasudil group (P < 0.01), which also demonstrated a higer ratio of axon-endplate connection and a larger size of endplates (P < 0.05). And there were no significant differences for the abovementioned parameters between the control and Fas + LY groups (P＞0.05). In vitro studies showed that Fasudil could significantly promote axon growth in DRG and SMNs, and increase the expression of p-PI3K and p-AKT, which could be abolished by LY294002 (P < 0.05). ConclusionsFasudil can augment axon regeneration and remyelination, and functional recovery after sciatic nerve injury by activating the PI3K/AKT pathway. The translational potential of this articleThe translation potential of this article is that we report for the first time that Fasudil Hydrochloride has a remarkable efficacy at improving axon regeneration and remyelination following a transection injury of the right sciatic nerve in rats through the ROCK/PI3K/AKT pathway, which has a translational potential to be used clinically to treat peripheral nerve injury.