Enhancing regeneration and repair of long-distance peripheral nerve defect injuries with continuous microcurrent electrical nerve stimulation.

Introduction: Peripheral nerve injuries, especially those involving long-distance deficits, pose significant challenges in clinical repair. This study explores the potential of continuous microcurrent electrical nerve stimulation (cMENS) as an adjunctive strategy to promote regeneration and repair in such cases. Methods: The study initially optimized cMENS parameters and assessed its impact on Schwann cell activity, neurotrophic factor secretion, and the nerve regeneration microenvironment. Subsequently, a rat sciatic nerve defect-bridge repair model was employed to evaluate the reparative effects of cMENS as an adjuvant treatment. Functional recovery was assessed through gait analysis, motor function tests, and nerve conduction assessments. Additionally, nerve regeneration and denervated muscle atrophy were observed through histological examination. Results: The study identified a 10-day regimen of 100uA microcurrent stimulation as optimal. Evaluation focused on Schwann cell activity and the microenvironment, revealing the positive impact of cMENS on maintaining denervated Schwann cell proliferation and enhancing neurotrophic factor secretion. In the rat model of sciatic nerve defect-bridge repair, cMENS demonstrated superior effects compared to control groups, promoting motor function recovery, nerve conduction, and sensory and motor neuron regeneration. Histological examinations revealed enhanced maturation of regenerated nerve fibers and reduced denervated muscle atrophy. Discussion: While cMENS shows promise as an adjuvant treatment for long-distance nerve defects, future research should explore extended stimulation durations and potential synergies with tissue engineering grafts to improve outcomes. This study contributes comprehensive evidence supporting the efficacy of cMENS in enhancing peripheral nerve regeneration.

RNA sequencing of exosomes secreted by fibroblast and Schwann cells elucidates mechanisms underlying peripheral nerve regeneration.

JOURNAL/nrgr/04.03/01300535-202408000-00035/figure1/v/2023-12-16T180322Z/r/image-tiff Exosomes exhibit complex biological functions and mediate a variety of biological processes, such as promoting axonal regeneration and functional recovery after injury. Long non-coding RNAs (lncRNAs) have been reported to play a crucial role in axonal regeneration. However, the role of the lncRNA-microRNA-messenger RNA (mRNA)-competitive endogenous RNA (ceRNA) network in exosome-mediated axonal regeneration remains unclear. In this study, we performed RNA transcriptome sequencing analysis to assess mRNA expression patterns in exosomes produced by cultured fibroblasts (FC-EXOs) and Schwann cells (SC-EXOs). Differential gene expression analysis, Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes analysis, and protein-protein interaction network analysis were used to explore the functions and related pathways of RNAs isolated from FC-EXOs and SC-EXOs. We found that the ribosome-related central gene Rps5 was enriched in FC-EXOs and SC-EXOs, which suggests that it may promote axonal regeneration. In addition, using the miRWalk and Starbase prediction databases, we constructed a regulatory network of ceRNAs targeting Rps5, including 27 microRNAs and five lncRNAs. The ceRNA regulatory network, which included Ftx and Miat, revealed that exsosome-derived Rps5 inhibits scar formation and promotes axonal regeneration and functional recovery after nerve injury. Our findings suggest that exosomes derived from fibroblast and Schwann cells could be used to treat injuries of peripheral nervous system.

Bugan Rongjin decoction alleviates inflammation and oxidative stress to treat the postmenopausal knee osteoarthritis through Wnt signaling pathway.

BACKGROUND: Traditional Chinese medicine has been found effective for the therapy of knee osteoarthritis (KOA). This study was aimed at investigating the underlying mechanism of Bugan Rongjin decoction (BGRJ) in treating the postmenopausal KOA. RESULTS: Ovariectomized rat model of KOA and LPS-induced chondrocytes were successfully constructed for in vivo and in vitro model of postmenopausal KOA. X-ray and hematoxylin-eosin (H&E) staining showed that BGRJ alleviated pathological damage of articular cartilage in OVX rats with KOA. In addition, BGRJ inhibited inflammation and oxidative stress through decreasing the levels of serum IL-6, IL-1ß, TNF-α and NO and regulated Wnt signaling pathway by downregulating the expression of Wnt5a and ß-catenin and upregulating the expression of Sox9 and Collagen II in cartilage tissue, detected by immunohistochemistry (IHC) and western blot analysis. Furthermore, Wnt5a silencing reduced the apoptosis of LPS-induced ADTC5 cells, which was further suppressed by the combination of downregulation of Wnt5a and BGRJ. CONCLUSIONS: In summary, BGRJ alleviates inflammation and oxidative stress to treat the postmenopausal KOA through Wnt signaling pathway.

A network pharmacology strategy to investigate the anti-osteoarthritis mechanism of main lignans components of Schisandrae Fructus.

Osteoarthritis (OA) is a chronic age-related progressive joint disorder. Degradation of the cartilage extracellular matrix (ECM) is considered a hallmark of OA and may be a target for new therapeutic methods. Schisandrae Fructus (SF) has been shown to be effective in treating OA. The major active components of SF are lignans. However, the targets of SF and the pharmacological mechanisms underlying the effects of SF lignans in the treatment of OA have not been elucidated. Therefore, based on network pharmacology, this research predicted the treatment targets of six lignans in SF, constructed a protein-protein interaction network and identified 15 hub genes in the OA-target protein-protein interaction network. Through Gene Ontology function and pathway analyses, the gene functions of lignans in the treatment of OA were determined. Finally, the anti-OA effects of lignans and underlying mechanisms identified in the network pharmacology analysis were verified by molecular docking, real-time PCR and western blotting in vitro. The biological processes of the genes and proteins targeted by lignans in the treatment of OA included the immune response, inflammatory response, cell signal transduction and phospholipid metabolism. Moreover, 20 metabolic pathways were enriched. Network pharmacology, molecular docking and in vitro and in vivo experimental results revealed that SF, schisanhenol and gamma-schisandrin inhibited EGFR and MAPK14 gene expression by inhibiting SRC gene expression and activity and then decreased MMP 13 and collagen II protein and gene expression. This research provides a basis for further study of the anti-OA effects and mechanisms of SF, schisanhenol and gamma-schisandrin.

Comparison of Therapeutic Effects of PVP and PKP Combined With Triple Medication on Mild and Moderate Osteoporotic Vertebral Compression Fracture in the Elderly.

Objective: To compare and analyze the therapeutic effect of percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) combined with triple therapy on elderly patients with mild to moderate osteoporotic vertebral compression fractures (OVCF). Methods: A total of 114 cases of elderly patients with mild to moderate osteoporotic vertebral compression fractures were identified as research subjects in our hospital from January 2017 to January 2018, and a total of 136 vertebrae were included. The patients who underwent PVP operation were included as the control group with 67 injured vertebrae, and the patients who underwent PKP operation were included as the experimental group with 69 injured vertebrae. Results: The operation time and bone cement injection volume of the experimental group were significantly higher than the control group. The visual analog scale (VAS) scores of the two groups at 3 months and 6 months after operation were lower than those before operation, with lower VAS scores observed in the experimental group at 3 months and 6 months after operation. The anterior height of the vertebral body in the experimental group was higher than that of the control group. The experimental group outperformed the control group in the incidence of postoperative complications. The postoperative Oswestry dysfunction index (ODI) scores of the two groups were lower before the operation, in which the experimental group had lower scores than the control group (P < 0.05). Conclusion: PVP and PKP combined with postoperative triple therapy can achieve a promising analgesic effect. PKP has a higher volume of bone cement injection volume, and a lower incidence of complications, which gives rise to a better vertebral body recovery height than that of PVP, with rapid postoperative body function recovery and good quality of life.

Correction to: The role of C-afferents in mediating neurogenic vasodilatation in plantar skin after acute sciatic nerve injury in rats.

An amendment to this paper has been published and can be accessed via the original article.

Comparative in vivo pharmacokinetics study of affeic acid, isoferulic acid and ferulic acid in crude and three different prepared Cimicifuga foetida L.

Our study investigated the differences in pharmacokinetics of three major components of crude Cimicifuga foetida L. and its fried product and honey- and liquor-prepared products. A rapid and sensitive ultra-high performance liquid chromatography with tandem mass spectrometry approach was established for determing caffeic acid, isoferulic acid and ferulic acid in rat plasma. The approach has good linearity, precision, accuracy, recovery and stability. Phenolic acid was rapidly absorbed. The times to peak concentration were shorter in the processed group than those for the crude product, with their values of <30 min. The peak concentration values of caffeic acid and isoferulic acid were higher in the crude group than in the processed groups (p < 0.05). Area under the curve values of the three phenolics in the crude group were significantly higher than those of the processed groups (p < 0.05).

The role of C-afferents in mediating neurogenic vasodilatation in plantar skin after acute sciatic nerve injury in rats.

BACKGROUND: Vasomotor regulation of dermal blood vessels, which are critical in the function of the skin in thermoregulatory control, involves both neural and non-neural mechanisms. Whereas the role of sympathetic nerves in regulating vasomotor activities is comprehensively studied and well recognized, that of sensory nerves is underappreciated. Studies in rodents have shown that severance of the sciatic nerve leads to vasodilatation in the foot, but whether sympathetic or sensory nerve fibers or both are responsible for the neurogenic vasodilatation remains unknown. RESULTS: In adult Sprague-Dawley rats, vasodilatation after transection of the sciatic nerve gradually diminished to normal within 3-4 days. The neurotmesis-induced neurogenic vasodilatation was not detectable when the sciatic nerve was chronically deafferentated by selective resection of the dorsal root ganglia (DRGs) that supply the nerve. Specific activation of C-afferents by intra-neural injection of capsaicin resulted in neurogenic vasodilatation to a magnitude comparable to that by neurotmesis, and transection of the sciatic nerve pre-injected with capsaicin did not induce further vasodilatation. CONCLUSIONS: Our results collectively indicate that vasodilatation after traumatic nerve injury in rats is predominantly mediated by C-fiber afferents.

Changes in transcriptome profiling during the acute/subacute phases of contusional spinal cord injury in rats.

BACKGROUND: Spinal cord injuries (SCIs), along with subsequent secondary injuries, often result in irreversible damage to both sensory and motor functions. However, a thorough view of the underlying pathological mechanisms of SCIs, especially in a temporal-spatial manner, is still lacking. METHODS: To obtain a comprehensive, real-time view of multiple subsets of the cellular mechanisms involved in SCIs, we applied RNA-sequencing technology to characterize the temporal changes in gene expression around the lesion site of contusion SCI in rats. First, we identified the differentially expressed genes (DEGs) in contrast to sham controls at 1, 4, and 7 days post SCI. Through bioinformatics analysis, including Pathway analysis, Gene-act-net, and Pathway-act-net, we screened and verified potential key pathways and genes associated with either the acute or subacute stages of SCI pathology. RESULTS: The top three overrepresented pathways were associated with cytokine-cytokine receptor interaction, TNF signaling pathway, and cell cycle at day 1; lysosome, cytokine-cytokine receptor interaction, phagosome at day 4; and phagosome, lysosome, cytokine-cytokine receptor interaction at day 7 post injury. Further, we identified uniquely enriched genes at each time point, such as Ccr1 and Nos2 at day 1; as well as Mgst2, and Pla2g3 at 4 and 7 days post-injury. CONCLUSIONS: Our pathway analysis suggested a transition from inflammatory responses to multiple forms of cell death processes from the acute to subacute stages of SCI. Further, our results revealed a continuous transformation from a more inflammatory to an apoptotic/self-repairing transcriptome following the time-course of SCIs. Our research provides novel insights into the molecular mechanisms of SCI pathophysiology and identifies potential targets for therapeutic intervention after SCI.

Axonotmesis-evoked plantar vasodilatation as a novel assessment of C-fiber afferent function after sciatic nerve injury in rats.

Quantitative assessment of the recovery of nerve function, especially sensory and autonomic nerve function, remains a challenge in the field of nerve regeneration research. We previously found that neural control of vasomotor activity could be potentially harnessed to evaluate nerve function. In the present study, five different models of left sciatic nerve injury in rats were established: nerve crush injury, nerve transection/suturing, nerve defect/autografting, nerve defect/conduit repair, and nerve defect/non-regeneration. Laser Doppler perfusion imaging was used to analyze blood perfusion of the hind feet. The toe pinch test and walking track analysis were used to assess sensory and motor functions of the rat hind limb, respectively. Transmission electron microscopy was used to observe the density of unmyelinated axons in the injured sciatic nerve. Our results showed that axonotmesis-evoked vasodilatation in the foot 6 months after nerve injury/repair recovered to normal levels in the nerve crush injury group and partially in the other three repair groups; whereas the nerve defect/non-regeneration group exhibited no recovery in vasodilatation. Furthermore, the recovery index of axonotmesis-evoked vasodilatation was positively correlated with toe pinch reflex scores and the density of unmyelinated nerve fibers in the regenerated nerve. As C-fiber afferents are predominantly responsible for dilatation of the superficial vasculature in the glabrous skin in rats, the present findings indicate that axonotmesis-evoked vasodilatation can be used as a novel way to assess C-afferent function recovery after peripheral nerve injury. This study was approved by the Ethics Committee for Laboratory Animals of Nantong University of China (approval No. 20130410-006) on April 10, 2013.

Injection of Fluoro-Gold into the tibial nerve leads to prolonged but reversible functional deficits in rats.

Tract tracing with neuronal tracers not only represents a straightforward approach to identify axonal projection connection between regions of the nervous system at distance but also provides compelling evidence for axonal regeneration. An ideal neuronal tracer meets certain criteria including high labeling efficacy, minimal neurotoxicity, rapid labeling, suitable stability in vivo, and compatibility to tissue processing for histological/immunohistochemical staining. Although labeling efficacy of commonly used fluorescent tracers has been studied extensively, neurotoxicity and their effect on neural functions remains poorly understood. In the present study, we comprehensively evaluated motor and sensory nerve function 2-24 weeks after injection of retrograde tracer Fluoro-Gold (FG), True Blue (TB) or Fluoro-Ruby (FR) in the tibial nerve in adult Spague-Dawley rats. We found that motor and sensory nerve functions were completely recovered by 24 weeks after tracer exposure, and that FG lead to a more prolonged delay in functional recovery than TB. These findings shed light on the long-term effect of tracers on nerve function and peripheral axonal regeneration, and therefore have implications in selection of appropriate tracers in relevant studies.

Combined Therapies of Modified Taiyi Miraculous Moxa Roll and Cupping for Patients with Lumbar Intervertebral Disc Herniation.

Lumbar intervertebral disc herniation is a kind of syndrome caused by stimulation or pressure of nerve root and cauda equina due to intervertebral disc disorder, fibrous ring rupture, and pulpiform nucleus protrusion. Application of traditional Chinese medicine (TCM) including acupuncture therapy and cupping therapy is unique and effective treatment for lumbar intervertebral disc herniation in China. Hence, we try to investigate the combined clinical efficacy of modified Taiyi miraculous moxa roll and cupping therapy on patients with lumbar intervertebral disc herniation. Seventy patients were randomly assigned into combined treatment group (n = 35) and control group (n = 35). The treatment group received combined therapy of modified Taiyi miraculous moxa roll and cupping therapy, while control group received acupuncture therapy alone. Diagnostic criteria of TCM syndrome, Japanese Orthopedic Association (JOA) score, and simplified McGill pain questionnaire (MPQ) were used to evaluate the therapy. 11 and 13 out of 35 subjects in the combined treatment group had improvement > 75% and between 50% and 75%, respectively. The corresponding number was 2 and 22 of 35 subjects in the acupuncture group. There was significant difference in the clinical efficacy between the treatment group and control group (P = 0.036). The scores of JOA and MPQ detected in the patients of the two groups (P < 0.05) also showed statistically significant differences. Moreover, no serious adverse events occurred in the patients, who received cupping therapy or acupuncture. The combined or alone therapies can effectively improve the treatment efficacy in the patients with lumbar intervertebral disc herniation, while the combined therapies show more comparative effectiveness. Furthermore, the combined therapies are potentially safe and cost-effective and also benefit the improvement of short-term pain. Therefore, the combined therapies of the two ancient TCM deserve further clinical applications.

Tubulation repair mitigates misdirection of regenerating motor axons across a sciatic nerve gap in rats.

The repair of peripheral nerve laceration injury to obtain optimal function recovery remains a big challenge in the clinic. Misdirection of regenerating axons to inappropriate target, as a result of forced mismatch of endoneurial sheaths in the case of end-to-end nerve anastomosis or nerve autografting, represents one major drawback that limits nerve function recovery. Here we tested whether tubulation repair of a nerve defect could be beneficial in terms of nerve regeneration accuracy and nerve function. We employed sequential retrograde neuronal tracing to assess the accuracy of motor axon regeneration into the tibial nerve after sciatic nerve laceration and entubulation in adult Sprague-Dawley rats. In a separate cohort of rats with the same sciatic nerve injury/repair protocols, we evaluated nerve function recovery behaviorally and electrophysiologically. The results showed that tubulation repair of the lacerated sciatic nerve using a 3-6-mm-long bioabsorbable guidance conduit significantly reduced the misdirection of motor axons into the tibial nerve as compared to nerve autografting. In addition, tubulation repair ameliorated chronic flexion contracture. This study suggests that tubulation repair of a nerve laceration injury by utilizing a bioresorbable nerve guidance conduit represents a potential substitute for end-to-end epineurial suturing and nerve autografting.

Long non­coding RNA FAF1 promotes intervertebral disc degeneration by targeting the Erk signaling pathway.

Intervertebral disc degeneration (IDD) has become the most common cause of low­back pain, and it imposes a heavy burden on patients with IDD and society. The effects of long non­coding RNAs on the proliferation and development of IDD have attracted increasing attention. The present study aimed to investigate the role and molecular mechanism of Fas­associated protein factor­1 (FAF1) in IDD. The expression of FAF1 was detected by reverse transcription­quantitative polymerase chain reaction. CCK­8 and immunofluorescence staining were used to determine cell proliferation. Flow cytometry was performed to measure the cell cycle and apoptosis. Western blotting was used to test p­Erk expression. The results of the present study demonstrated that the expression of FAF1 was upregulated in patients with disc bulging, herniation and IDD, and the expression of FAF1 was positively correlated with the grade of disc degeneration according to the patients' Pfirrmann score. The overexpression of FAF1 in nucleus pulposus (NP) cells promoted cell proliferation by increasing the percentage of cells in the S­phase of the cell cycle. The expression of phosphorylated extracellular signal­regulated kinase (Erk), a possible target of FAF1, was consistent with the expression of FAF1. In addition, it was elucidated that inactivation of the Erk signaling pathway by PD98059 reversed the effect of FAF1 on NP cell proliferation. Taken together, these results demonstrated that FAF1 was vital in the proliferation of NP cells by modulating the Erk signaling pathway, which suggests that FAF1 may be a novel marker in the early diagnosis of IDD and a therapeutic target for patients.

Periodical assessment of electrophysiological recovery following sciatic nerve crush via surface stimulation in rats.

When evaluating peripheral nerve regeneration, electrophysiological test is recognized as an optimal assessment, which is a quantitative, objective, and direct evidence reflecting function as compared to morphological examinations. In murine models of nerve regeneration, however, it remains a challenge to record compound muscle action potentials (CMAPs) periodically and non-invasively, i.e., with no insult to the nerve. In the present study, we recorded CMAPs in the gastrocnemius muscle weekly until 8 weeks after sciatic nerve crush by stimulating the nerve in a surface manner, and the electric stimuli were delivered to the skin between ischial tuberosity and major trochanter using bipolar hook electrodes. The CMAPs were reproducibly recorded in this way from 3 weeks post-injury, and both amplitude and latency were well correlated to post-operative time. Furthermore, a strong positive correlation was observed between CMAP amplitude and sciatic function index (SFI), a well-recognized assessment for sciatic nerve function. CMAP recordings by direct nerve stimulation at 8 weeks post-injury showed no significant difference in amplitude compared to surface stimulation, but the peak latency was relatively longer than the latter. This study indicated that non-invasive surface stimulation-based periodical recording of CMAPs was a practical electrophysiological approach to monitor the progression of peripheral nerve regeneration in murine models.