Search Results (203)

The use of Botulinum Neurotoxin A (BoNT/A) to treat peripheral neuropathic pain from nerve injury has garnered interest for its long-lasting effects and safety. This study examined the effects of IncobotulinumtoxinA (Inco/A), a BoNT/A variant without accessory proteins, on nerve regeneration in rats using the chronic constriction injury (CCI) model. Inco/A was administered perineurally at two time points: on days 0 and 21 post CCI. Functional and histological assessments were conducted to evaluate the effect of Inco/A on nerve regeneration. Sciatic Functional Index (SFI) measurements and Compound Muscle Action Potential (CMAP) recordings were conducted at different time points following CCI. Inco/A-treated animals exhibited a 65% improved SFI and 22% reduction in CMAP onset latencies compared to the vehicle-treated group, suggesting accelerated functional nerve recovery. Tissue analysis revealed enhanced remyelination in Inco/A-treated animals and 60% reduction in CGRP and double S100β signal expression compared to controls. Strikingly, 30% reduced immune cell influx into the injury site was observed following Inco/A treatment, suggesting that its anti-inflammatory effect contributes to nerve regeneration. These findings show that two injections of Inco/A promote functional recovery by enhancing neuroregeneration and modulating inflammatory processes, supporting the hypothesis that Inco/A has a neuroprotective and restorative role in nerve injury conditions. Full article

Disruption of circadian rhythms by abnormal light exposure and reduced melatonin secretion has been linked to heightened pain sensitivity and opioid tolerance. This study evaluated how environmental light manipulation and exogenous melatonin supplementation influence pain perception and morphine tolerance in a rat model of neuropathic pain induced by partial sciatic nerve transection (PSNT). Rats were exposed to constant darkness, constant light, or a 12 h/12 h light–dark cycle for one week before PSNT surgery. Behavioral assays and continuous intrathecal (i.t.) infusion of morphine, melatonin, or their combination were conducted over a 7-day period beginning immediately after PSNT. On Day 7, after discontinued drugs infusion, an acute intrathecal morphine challenge (15 µg, i.t.) was administered to assess tolerance expression. Constant light suppressed melatonin levels, exacerbated pain behaviors, and accelerated morphine tolerance. In contrast, circadian-aligned lighting preserved melatonin rhythms and mitigated these effects. Melatonin co-infusion attenuated morphine tolerance and enhanced morphine analgesia. Reduced pro-inflammatory cytokine expression and increase anti-inflammatory cytokine IL-10 level and suppressed astrocyte activation were also observed by melatonin co-infusion during morphine tolerance induction. These findings highlight the potential of melatonin and circadian regulation in improving opioid efficacy and reduced morphine tolerance in managing neuropathic pain. Full article

Background/Objectives: Nerve injuries cause functional loss and psychosocial issues due to prolonged rehabilitation. Recently, 3D-modeled nerve conduits have been used to aid in surgical planning. This study investigated the impact of 3D-bioprinted PLA, chitosan, alginate, and collagen conduits on nerve regeneration in a rat sciatic nerve crush injury model. Methods: This study, conducted at Kütahya University of Health Sciences, involves 50 rats were divided into four groups: (1) sham-operated controls, (2) sciatic nerve injury without treatment, (3) injury treated with a PLA conduit, and (4) injury treated with 3D-printed tubes composed of chitosan and alginate. The procedures were performed, blood was collected, and the rats were sacrificed after two months. Weekly checks for infection, scar healing, and motor responses were performed. Results: Rats with nerve conduits showed less macroscopic scarring. Weekly assessments of motor nerve recovery showed no movement restrictions in limbs treated with PLA conduits, graft conduits, or conduits bridging retracted nerve stumps, based on responses to stimulus checks. An infection developed in the sciatic nerve and surrounding muscle tissue of one rat with a bio-graft conduit, prompting histopathological examination to investigate its cause. Conclusions: This proof-of-principle study demonstrates the feasibility of using 3D-printed biocompatible nerve conduits for peripheral nerve repair, providing a basis for future, more comprehensive investigations. Full article

Background: Numerous experimental studies aim to improve outcomes of peripheral nerve repair following trauma. This study evaluates the efficacy of the human epineural patch (hEP) compared to the human amniotic membrane (hAM) in promoting nerve regeneration following sciatic nerve crush injury. Methods: Thirty-six athymic nude rats were divided into three groups (n = 12 per group) following nerve crush: (1) an unprotected injury site; (2) crush injury wrapped with hEP; and (3) crush injury wrapped with hAM. Animals were assessed over 6 or 12 weeks post-injury. Evaluations included motor recovery (Toe-Spread test), sensory recovery (Pinprick test), muscle denervation atrophy (the gastrocnemius muscle index (GMI)), histomorphometry (myelin thickness, axonal density, fiber diameter, and percentage of myelinated fibers), and immunofluorescence (GFAP, Laminin B, NGF, S-100, VEGF, vWF, HLA-DR, and HLA-I) assessments. Results: The hEP group showed superior motor recovery, axonal density and higher GMI values compared to the hAM and control groups. The increased expression of neurogenic and angiogenic markers highlighted its neuroregenerative potential. Negligible HLA-DR and HLA-I expression confirmed the lack of hEP and hAM immunogenicity. Conclusions: The application of hEP following sciatic nerve crush injury facilitated nerve regeneration, improved functional outcomes, and offered a viable alternative to hAM. Structural stability and the regenerative capacity position hEP as a new, promising off-the-shelf product for nerve regeneration. Full article

Background and Objectives: We have previously reported that omega-3 polyunsaturated fatty acids (PUFAs) derived from fish oil (FO) is an effective treatment for type 1 and type 2 diabetes neural and vascular complications. As omega-3 PUFAs become more widely used as a nutritional and disease modifying supplement an important question to be addressed is what is the preferred source of omega-3 PUFAs? Methods: Using a type 2 diabetic rat model and early and late intervention protocols we examined the effect of dietary treatment with omega-3 PUFAs derived from menhaden (fish) oil (MO), krill oil (KO), algal oils consisting primarily of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or combination of EPA + DHA, or pharmaceutical-derived ethyl esters of EPA, DHA or combination of EPA + DHA. Nerve related endpoints included motor and sensory nerve conduction velocity, heat sensitivity of the hind paw, intraepidermal nerve density, cornea nerve fiber length, and cornea sensitivity. Vascular reactivity to acetylcholine and calcitonin gene-related peptide by epineurial arterioles that provide blood to the sciatic nerve was also examined. Results: The dose of each omega-3 PUFA supplement increased the content of EPA, docosapentaenoic acid (DPA), and/or DHA in red blood cell membranes, serum and liver. Diabetes caused a significant decrease of 30–50% of neural function and fiber occupancy of the skin and cornea and vascular reactivity. Treatment with MO, KO or the combination of EPA + DHA provided through algal oil or ethyl esters provided significant improvement of each neural endpoint and vascular function. Algal oil or ethyl ester of EPA alone was the least effective with algal oil or ethyl ester of DHA alone providing benefit that approached combination therapies for some endpoints. Conclusions: We confirm that omega-3 PUFAs are an effective treatment for DPN and sources other than fish oil are similarly effective. Full article

Docetaxel is extensively used for treating different types of cancer; however, its clinical efficacy is primarily limited by myelotoxicity and peripheral neuropathy, adverse effects that often lead to treatment discontinuation. This study aimed to establish a preclinical model in Wistar rats for the simultaneous induction of myelotoxicity and peripheral neuropathy associated with docetaxel administration, enabling the evaluation of potential chemopreventive agents. Four distinct docetaxel administration schemes were assessed by performing behavioral nociceptive tests and complete blood cell counts. After establishing the damage model (5 mg/kg/week docetaxel for six weeks), we co-administered 100 mg/kg/week oral dimethyl fumarate to assess its protective effect. Dimethyl fumarate attenuated docetaxel-induced hyperalgesia, likely through preserving normal nerve fiber density in sciatic nerves, but neutropenia was not significantly mitigated. An alternative regimen with additional pre-administered doses of dimethyl fumarate showed a trend toward neutropenia attenuation and suggested an interesting inhibition of docetaxel-induced rat vibrissae loss. Chou-Talalay isobolographic analyses on prostate cancer cell lines revealed that dimethyl fumarate does not impair the therapeutic effect of docetaxel at most combination ratios evaluated; rather, synergistic effects were observed. This experimental model proved useful and will facilitate further research into the protective role of dimethyl fumarate and other potential chemoprotective agents. Full article

This study aimed to investigate the relationship between microglial activity and gut microbiota composition in a rat model of neuropathic pain (NP), and to evaluate how pregabalin treatment may influence these interrelated parameters. NP was simulated in rats via ligation and transection of the sciatic nerve. After confirming NP, the rats were randomly divided into treatment and control groups. Pregabalin (10 mg/kg) and the same dose of normal saline were administered to the treatment and control groups, respectively, on scheduled days. Microglial activity, cytokine levels, and the composition of the gut microbiota (assessed by the Firmicutes/Bacteroidetes (F/B) ratio) were evaluated. Pregabalin treatment significantly reduced microglial activity (which was notably lower in the treatment group than in the control group) and modulated pro-inflammatory and anti-inflammatory cytokine levels. While the F/B ratio in the control group significantly increased after NP surgery, the treatment group showed an initial increase followed by a notable decrease, approaching pre-surgery levels by day 28. This finding suggests that pregabalin treatment in rats with NP ameliorates microglial activity and is associated with a beneficial shift in the gut microbiota composition. Full article

Background/Objectives: Previous work in our lab demonstrated that a 3D scaffold containing lysine-modified chitosan (K-chitosan) and decorated with Matrilin-2 (MATN2) enhanced Schwann cell (SC) migration and axonal outgrowth in vitro and ex vivo. This study aimed to assess the regenerative effect of this scaffold compared to that of a collagen conduit and an autograft using a segmental rat sciatic nerve injury model. Methods: A total of 30 Lewis Rats were assigned into three groups: an untreated collagen conduit (UC) group, a collagen conduit treated with MATN2 K-chitosan (TC) group, and a reverse autograft (RA) group. Walking force measurements, compound muscle action potential (CMAP), the wet muscle weight of the tibialis anterior and the gastrocnemius, and axonal histomorphometry were assessed. Results: The walking force and CMAP were significantly higher in the TC group compared to those in the UC group, with no significant difference between the TC and RA groups. The muscle weights were significantly greater in the TC group compared to those in the UC group but smaller than those in the RA group. The TC group experienced significantly greater axonal regeneration compared to that with the UC, and no differences were found with the RA. The TC group further demonstrated significantly greater cell counts than those in the UC group and greater affinity of the Schwann cells towards nerve reconstruction. Conclusion: The MATN2 K-chitosan scaffold significantly improved nerve regeneration and was comparable to the RA, supporting the development of a novel bio-conductive scaffold conduit. Full article

Peripheral nerve injuries are a significant concern in surgical procedures, often leading to chronic pain and functional impairment. Despite advancements in imaging, preoperative and intraoperative visualization of peripheral nerves remains a challenge. This study introduces and evaluates a novel tri-iodinated lidocaine-based contrast agent for computed tomography neurography, aiming to enhance the intraoperative visibility of peripheral nerves in vivo. A tri-iodinated lidocaine analogue was synthesized and characterized for its radiodensity, sodium channel binding and nerve affinity. Sodium channel affinity was performed using molecular docking. In vitro contrast enhancement was assessed by comparing the agent’s Hounsfield unit (HU) values with those of Omnipaque, a clinically approved contrast medium. In vivo imaging was conducted on rat sciatic nerves using micro-CT, followed by ex vivo validation. Nerve conduction blockade was assessed via electrical stimulation and histological analysis was performed to evaluate neurotoxicity. Experimental results revealed the tri-iodinated lidocaine analogue to have similar or higher affinity toward voltage-gated sodium channels than the parent lidocaine and a radiodensity comparable to the commercial CT contrast agent Omnipaque in vitro. In vivo, the contrast agent provided CT visualization of the sciatic nerve, with a significant increase in HU values compared to untreated nerves. Electrical stimulation confirmed transient nerve conduction blockade without observable histological damage, supporting its dual role as an imaging and nerve-blocking agent. This study presents a novel tri-iodinated lidocaine-based contrast agent that enables clear CT visualization of peripheral nerves while maintaining reversible nerve inhibition. These findings support its potential application in preoperative planning and intraoperative nerve protection to reduce surgical nerve injuries. Further studies are warranted to optimize imaging conditions and evaluate its clinical feasibility. Full article

Background: Peripheral nerves have a certain regenerative ability, but their repair and regeneration after injury is a complex process, usually involving a large number of genes and proteins. In a previous study, we analyzed the gene expression profile in rats after sciatic nerve injury and found significant changes in transforming growth factor-beta 1 (TGF-β1) expression, suggesting that TGF-β1 may be involved in the process of nerve regeneration after injury. Methods: In this study, we first detected the time-course expression and localization of TGF-β1 in dorsal root ganglion (DRG) tissues in a rat sciatic nerve transection model via RT-qPCR. Secondly, we investigated the bioactive roles of TGF-β1 in primary cultured DRG neuron cells through a CCK8 assay, TUNEL assay, and immunofluorescence staining. Thirdly, we explored the neuroprotective roles of TGF-β1 in an in vivo model of sciatic nerve regeneration through morphological observation, behavioral, and electrophysiological tests, and a molecular biological measure. Results: We found that TGF-β1 expression was increased after injury and mainly located in the cytoplasm and nuclei of neuron cells in the DRG. TGF-β1 may regulate the viability, apoptosis, and neurite outgrowth of primary DRG neuron cells. In our in vivo model of sciatic nerve regeneration, TGF-β1 improved nerve regeneration and neuronal function recovery after sciatic nerve injury, alleviated the inflammatory response, and relieved neuropathic pain via the TGF-β1/smad2 pathway. Conclusions: This study provides an experimental and theoretical basis for using TGF-β1 as a neuroprotective agent after peripheral nerve injury in clinical practice in the future. Full article

Peripheral nerve injury (PNI) remains a significant clinical challenge, often leading to long-term functional impairment. Despite advances in therapies, current repair strategies offer unsatisfactory clinical outcomes. Exosomes derived from induced pluripotent stem cells (iPSC-Exos) have emerged as a promising therapeutic approach in regenerative medicine. This study assesses the efficacy and safety of iPSC-Exos in a rat model of sciatic nerve crush injury. Briefly, iPSCs were generated from peripheral blood mononuclear cells (PBMCs) of healthy donors using Sendai virus vectors and validated for pluripotency. iPSC-Exos were characterized and injected at the injury site. Functional recovery was assessed through gait analysis, grip strength, and pain response. Histological and molecular analyses were used to examine axonal regeneration, myelination, Schwann cell (SC) activation, angiogenesis, and changes in gene expression. iPSC-Exos were efficiently internalized by SC, promoting their proliferation. No adverse effects were observed between groups on body weight, organ histology, or hematological parameters. iPSC-Exos injection significantly enhanced nerve regeneration, muscle preservation, and vascularization, with RNA sequencing revealing activation of PI3K-AKT and focal adhesion pathways. These findings support iPSC-Exos as a safe and effective non-cell-based therapy for PNIs, highlighting their potential for clinical applications in regenerative medicine. Full article

Background and Objectives: Peripheral nerve injuries often result in significant functional impairment, and complete recovery remains challenging despite surgical interventions. Polyethylene glycol (PEG) has shown promise in nerve repair by facilitating axonal fusion and inhibiting Wallerian degeneration. This study investigates the biochemical, histopathological, and electrophysiological effects of PEG 3350 in a sciatic nerve injury model. Materials and Methods: Thirty adult male Wistar rats were divided into three groups: a control group, a surgery and saline group, and a surgery and PEG 3350 treatment group. Sciatic nerve transection was performed, and PEG 3350 was administered intraperitoneally for 12 weeks. Electromyography (EMG) and the inclined plane test assessed functional recovery. Sciatic nerve tissues were analyzed histologically and biochemically, including nerve growth factor (NGF), heat shock protein 70 (HSP-70), and malondialdehyde (MDA) levels. Results: PEG 3350 significantly improved electrophysiological parameters, reducing compound muscle action potential (CMAP) latency and increasing CMAP amplitude compared to the saline group (p < 0.05). Functional recovery, assessed by the inclined plane test, showed a significant improvement in the PEG-treated group (p < 0.01). Biochemical analysis revealed increased NGF and HSP-70 levels, suggesting enhanced neuroprotection and regeneration. Histopathological analysis demonstrated reduced fibrosis and increased axonal density in the PEG group compared to controls. PEG 3350 enhances nerve regeneration by improving electrophysiological function, promoting axonal repair, and increasing neurotrophic factor expression. Conclusions: These findings suggest PEG as a potential adjunct therapy for peripheral nerve injuries. Future research should explore the optimal administration protocols and combined therapeutic strategies for maximizing recovery. Full article

Spinal cord injury (SCI) affects millions of people worldwide. One of the main challenges of rehabilitation strategies is re-training and enhancing the plasticity of the spinal circuitry that was preserved or rebuilt after the injury. The serotonergic system appears to be crucial in these processes, since recent studies have reported the capability of serotonergic (5-HT) axons for axonal sprouting and regeneration in response to central nervous system (CNS) trauma or neurodegeneration. We took advantage of tryptophan hydroxylase 2 knockout (TPH2 KO) rats, lacking serotonin specifically in the brain and spinal cord, to study the role of the serotonergic system in the recovery of sensorimotor function after SCI. In the present work, we compared the rate of sensorimotor recovery of TPH2 KO and wild-type (WT) female rats after SCI (lateral hemisection at the T8 spinal level). SCI caused severe motor impairments in the ipsilateral left hindlimb, the most pronounced in the first week after the hemisection with gradual functional recovery during the following 3 weeks. The results demonstrate that TPH2 KO rats have less potential to recover motor functions since the degree of sensorimotor deficit in the tapered beam walking test (TBW) and ladder walking test (LW) was significantly higher in the TPH2 KO group in comparison to the WT animals in the 3rd and 4th weeks after SCI. The recovery dynamics of the hindlimb muscle tone and voluntary movements was in agreement with the restoration of motor performance in TBW and LW. Compound muscle action potential analysis in the gastrocnemius (GM) and tibialis (TA) muscles of both hindlimbs after electrical stimulation of the sciatic nerve or lumbar region (L5–L6) of the spinal cord indicated slower recovery of sensorimotor pathways in the TPH2 KO group versus their WT counterparts. In general, the observed results confirm the significance of central serotonergic mechanisms in the recovery of sensorimotor functions in rats and the relevance of the TPH2 KO rat model in studying the role of the 5-HT system in neurorehabilitation. Full article

Neuropathic pain (NP) is a type of chronic pain resulting from injury or dysfunction of the nerves or spinal cord. Previous studies have shown that the combination of ligustrazine (LGZ) and sinomenine (SIN) exerts a synergistic antinociceptive effect in peripheral and central NP models. On this basis, a comprehensive analgesic evaluation was performed in a chronic constriction injury (CCI)-induced NP model in rats. Sciatic nerve histopathological changes were observed, and 22 cytokines and chemokines levels were analyzed. We also combined network pharmacology and metabolomics to explore their molecular mechanisms. Results showed that the combination of LGZ and SIN significantly alleviated the pain-like behaviors in CCI rats in a time- and dose-dependent manner, demonstrating superior therapeutic effects compared to LGZ or SIN alone. It also improved pathological damage to sciatic nerves and regulated inflammatory cytokine levels. Network pharmacology identified shared and distinct pain-related targets for LGZ and SIN, while metabolomics revealed 54 differential metabolites in plasma, and 17 differential metabolites in CSF were associated with the combined intervention of LGZ and SIN. Finally, through an integrated analysis of the core targets and differential metabolites, tyrosine metabolism, phenylalanine metabolism, and arginine and proline metabolism were identified as potential key metabolic pathways underlying the therapeutic effects of LGZ and SIN in CCI treatment. In conclusion, our study provides evidence to support the clinical application of LGZ and SIN in the treatment of NP. Full article

Background and Objectives: Peripheral nerve defect regeneration is subject to ongoing research regarding the use of conduits associated with various cells or molecules. This article aims to correlate histopathological and clinical outcomes at the end of a 12-week experiment performed on a rat sciatic nerve model and show which repair method has the best results. Materials and Methods: Forty male Wistar rats were divided into four groups to compare the results of four different methods of reconstruction for sciatic nerve defect: (1) nerve graft–control group, (2) empty aortic conduit, (3) aortic conduit filled with platelet-rich plasma (PRP) and (4) aortic conduit filled with mesenchymal stem cells. There were three clinical examinations: a sensitivity test, a mobility test and a footprint test. After 12 weeks, the nerves were excised and assessed microscopically using conventional Hematoxylin and Eosin staining (HE), special stains and immunohistochemistry (IHC). Results: Nerve regeneration was observed in all batches, both from the clinical and histopathological assessment; the two types of examinations correlated for each batch. Immunohistochemistry and special staining offered a more complete image of the nerve regeneration results. Conclusions: Superior nerve regeneration was achieved using an aortic conduit in combination with either PRP or stem cells, while the empty aortic conduit recorded lesser results. Full article