Photobiomodulation promotes spinal cord injury repair by inhibiting macrophage polarization through lncRNA TUG1-miR-1192/TLR3 axis.

BACKGROUND: Secondary spinal cord injury (SCI) often causes the aggravation of inflammatory reaction and nerve injury, which affects the recovery of motor function. Bone-marrow-derived macrophages (BMDMs) were recruited to the injured area after SCI, and the M1 polarization is the key process for inducing inflammatory response and neuronal apoptosis. We previously showed that photobiomodulation (PBM) can inhibit the polarization of M1 phenotype of BMDMs and reduce inflammation, but the underlying mechanisms are unclear. The purpose of this study is to explore the potential target and mechanism of PBM in treating SCI. METHODS: Transcriptome sequencing and bioinformatics analysis showed that long noncoding RNA taurine upregulated gene 1 (lncRNA TUG1) was a potential target of PBM. The expression and specific mechanism of lncRNA TUG1 were detected by qPCR, immunofluorescence, flow cytometry, western blotting, fluorescence in situ hybridization, and luciferase assay. The Basso mouse scale (BMS) and gait analysis were used to evaluate the recovery of motor function in mice. RESULTS: Results showed that lncRNA TUG1 may be a potential target of PBM, regulating the polarization of BMDMs, inflammatory response, and the axial growth of DRG. Mechanistically, TUG1 competed with TLR3 for binding to miR-1192 and attenuated the inhibitory effect of miR-1192 on TLR3. This effect protected TLR3 from degradation, enabling the high expression of TLR3, which promoted the activation of downstream NF-κB signal and the release of inflammatory cytokines. In vivo, PBM treatment could reduce the expression of TUG1, TLR3, and inflammatory cytokines and promoted nerve survival and motor function recovery in SCI mice. CONCLUSIONS: Our study clarified that the lncRNA TUG1/miR-1192/TLR3 axis is an important pathway for PBM to inhibit M1 macrophage polarization and inflammation, which provides theoretical support for its clinical application in patients with SCI.

Photobiomodulation and diffusing optical fiber on spinal cord's impact on nerve cells from normal spinal cord tissue in piglets.

Experts have proven that photobiological regulation therapy for spinal cord injury promotes the spinal repair following injury. The traditional irradiation therapy mode is indirect (percutaneous irradiation), which could significantly lower the effective use of light energy. In earlier studies, we developed an implantable optical fiber that one can embed above the spinal cord lamina, and the light directly is cast onto the surface of the spinal cord in a way that can dramatically improve energy use. Nonetheless, it remains to be seen whether near-infrared light diffused by embedded optical fiber can have side effects on the surrounding nerve cells. Given this, we implanted optical fiber on the lamina of a normal spinal cord to observe the structural integrity of the tissue using morphological staining; we also used immunohistochemistry to detect inflammatory factors. Considering the existing studies, we meant to determine that the light energy diffused by embedded optical fiber has no side effect on the normal tissue. The results of this study will lay a foundation for the clinical application of the treatment of spinal cord injury by near-infrared light irradiation.

Clinical safety study of photobiomodulation in acute spinal cord injury by scattering fiber.

The study aimed to design a reliable and straightforward PBM method by implanting a medical scattering fiber above surgically exposed spinal cord in SCI patients. Moreover, the safety of this method was examined. Twelve patients with acute SCI (ASIA B) requiring posterior decompression were recruited. The medical scattering fiber was implanted above the spinal cord, and was continuously irradiated at 810 nm, 300 mW, 30 min/day, once per day for 7 days. The vital signs (temperature, blood pressure, respiratory rate, heart rate, and oxygen saturation), infection indicators (WBC, NEUT, hs-CRP, and PCT), photo-allergic reaction indicators (Eosinophil and Basophil), coagulation function indicators (PT, APTT, TT) and neurological stability indicators (ASIA sensory and motor scores) were recorded to evaluate the safety of PBM. Three months after surgery, 12 patients completed follow-up. In our study, direct PBM on SCI site did not cause clinically pathologic changes in vital signs of the patients. All patients had higher WBC, NEUT, and hs-CRP at day 3 during irradiation than those before surgery, and returned to normal at day 7. The changes in Eosinophil and Basophil that were closely associated with allergic reactions were within normal limits throughout the course of irradiation. The coagulation function (PT, APTT, and TT) of patients were also in the normal range. The ASIA sensory and motor scores of all patients had no changes throughout the irradiation process. However, in the follow-up, both ASIA sensory and motor scores of all patients had minor improvement than those in pre-irradiation, and 7 patients had adverse events, but they were not considered to be related to PBM. Our study might firstly employ direct PBM in the SCI by using scattered optical fibers. In a limited sample size, our study concluded that direct PBM at the site of SCI would not produce adverse effects within the appropriate irradiation parameters. The method is safe, feasible, and does not add additional trauma to the patient. Our preliminary study might provide a new methodology for the clinical PBM treatment of acute SCI.

RIP2 knockdown inhibits cartilage degradation and oxidative stress in IL-1ß-treated chondrocytes via regulating TRAF3 and inhibiting p38 MAPK pathway.

Receptor-interacting protein 2 (RIP2) is a key mediator implicated in multiple cellular processes, and its dysregulation has been recently reported in colitis, asthma and other inflammatory diseases. However, the effects of RIP2 on osteoarthritis (OA) and the underlying mechanisms remain unclear. In this study, we found that RIP2 expression was upregulated in human articular cartilage tissues with OA and interleukin-1ß (IL-1ß)-treated chondrocytes. Knockdown of RIP2 inhibited IL-1ß-induced extracellular matrix (ECM) and oxidative stress. Moreover, knockdown of TRAF3 reversed the effects of RIP2 silencing on cartilage degradation and oxidative stress in IL-1ß-induced chondrocytes. In addition, p38 mitogen-activated protein kinase (MAPK) activator dehydrocorydalmine chloride (Dc) also reversed the effects of RIP2 silencing on IL-1ß-induced chondrocytes. Taken together, our data reveal that RIP2 knockdown inhibits cartilage degradation and oxidative stress in IL-1ß-treated chondrocytes by regulating TRAF3 expression and p38 MAPK pathway activation.

Photobiomodulation inhibits the activation of neurotoxic microglia and astrocytes by inhibiting Lcn2/JAK2-STAT3 crosstalk after spinal cord injury in male rats.

BACKGROUND: Neurotoxic microglia and astrocytes begin to activate and participate in pathological processes after spinal cord injury (SCI), subsequently causing severe secondary damage and affecting tissue repair. We have previously reported that photobiomodulation (PBM) can promote functional recovery by reducing neuroinflammation after SCI, but little is known about the underlying mechanism. Therefore, we aimed to investigate whether PBM ameliorates neuroinflammation by modulating the activation of microglia and astrocytes after SCI. METHODS: Male Sprague-Dawley rats were randomly divided into three groups: a sham control group, an SCI + vehicle group and an SCI + PBM group. PBM was performed for two consecutive weeks after clip-compression SCI models were established. The activation of neurotoxic microglia and astrocytes, the level of tissue apoptosis, the number of motor neurons and the recovery of motor function were evaluated at different days post-injury (1, 3, 7, 14, and 28 days post-injury, dpi). Lipocalin 2 (Lcn2) and Janus kinase-2 (JAK2)-signal transducer and activator of transcription-3 (STAT3) signaling were regarded as potential targets by which PBM affected neurotoxic microglia and astrocytes. In in vitro experiments, primary microglia and astrocytes were irradiated with PBM and cotreated with cucurbitacin I (a JAK2-STAT3 pathway inhibitor), an adenovirus (shRNA-Lcn2) and recombinant Lcn2 protein. RESULTS: PBM promoted the recovery of motor function, inhibited the activation of neurotoxic microglia and astrocytes, alleviated neuroinflammation and tissue apoptosis, and increased the number of neurons retained after SCI. The upregulation of Lcn2 and the activation of the JAK2-STAT3 pathway after SCI were suppressed by PBM. In vitro experiments also showed that Lcn2 and JAK2-STAT3 were mutually promoted and that PBM interfered with this interaction, inhibiting the activation of microglia and astrocytes. CONCLUSION: Lcn2/JAK2-STAT3 crosstalk is involved in the activation of neurotoxic microglia and astrocytes after SCI, and this process can be suppressed by PBM.

Clinical efficacy and therapeutic value of delayed surgery in patients with symptomatic old thoracolumbar fractures.

BACKGROUND: To investigate the clinical efficacy and therapeutic value of posterior decompression reduction, bone grafting fusion, and internal fixation for treatment of symptomatic old thoracolumbar fractures. METHOD: Retrospective analysis was conducted for 14 patients (9 men, 5 women; average age 40.1 years) with old thoracolumbar fractures who underwent posterior operation. American Spinal Injury Association (ASIA) scores were used to evaluate neurologic function. Vertebral body height, Cobb angle in the sagittal plane, spinal canal volume ratio (%) and bone graft fusion were analyzed by radiography and computed tomography on different follow-up times. RESULTS: Mean follow-up was 27.1 months (23-36 months). Of three patients with ASIA grade A, 2 had improved postoperative urination and defecation, although no classification change. Preoperative ASIA score for eight patients with incomplete injury was grade B; four patients recovered to grade C at final follow-up. Preoperative ASIA score was C in three patients, increased to D in two patients and returned to normal E in one patient. Preoperative results showed average injured vertebra height loss rate decreased from 50.4 to 8.9%; average Cobb angle on the sagittal plane recovered from 39.6 to 6.9°; and the average spinal canal volume ratio recovered from 33.8 to 5.9%. Bony fusion was achieved; local lumbago and leg pain were relieved to some extent. No patients exhibited loosening of the fracture treated by internal fixation, pseudoarthrosis, or other related serious complications. CONCLUSION: Treatment of old thoracolumbar fractures by posterior decompression reduction, bone grafting fusion, and internal fixation can relieve spinal cord compression, improve neurologic function of some patients (ASIA grades B-C), effectively relieve pain, correct deformity, restore biomechanical stability, and significantly improve quality of life.

Low-level laser therapy 810-nm up-regulates macrophage secretion of neurotrophic factors via PKA-CREB and promotes neuronal axon regeneration in vitro.

Macrophages play key roles in the secondary injury stage of spinal cord injury (SCI). M1 macrophages occupy the lesion area and secrete high levels of inflammatory factors that hinder lesion repair, and M2 macrophages can secrete neurotrophic factors and promote axonal regeneration. The regulation of macrophage secretion after SCI is critical for injury repair. Low-level laser therapy (810-nm) (LLLT) can boost functional rehabilitation in rats after SCI; however, the mechanisms remain unclear. To explore this issue, we established an in vitro model of low-level laser irradiation of M1 macrophages, and the effects of LLLT on M1 macrophage polarization and neurotrophic factor secretion and the related mechanisms were investigated. The results showed that LLLT irradiation decreased the expression of M1 macrophage-specific markers, and increased the expression of M2 macrophage-specific markers. Through forward and reverse experiments, we verified that LLLT can promote the secretion of various neurotrophic factors by activating the PKA-CREB pathway in macrophages and finally promote the regeneration of axons. Accordingly, LLLT may be an effective therapeutic approach for SCI with clinical application prospects.

Photobiomodulation Therapy Inhibit the Activation and Secretory of Astrocytes by Altering Macrophage Polarization.

Spinal cord injury (SCI) stimulates reactive astrogliosis and the infiltration of macrophages, which interact with each other at the injured area. We previously found Photobiomodulation (PBM) significantly decreases the number of M1 macrophages at the injured area of SCI. But the exact nature of the astrocyte response following PBM and relationship with the macrophage have not been explored in detail. In this study, a BALB/c mice model with standardized bilateral spinal cord compression and a macrophage-astrocyte co-culture model were applied to study effects of PBM on astrocytes. Results showed that PBM inhibit the expression of the astrocyte markers glial fibrillary acidic protein (GFAP) and the secretion of chondroitin sulfate proteoglycans (CSPG) in the para-epicenter area, decrease the number of M1 macrophage in vivo. The in vitro experiments indicated M1 macrophages promote the cell viability of astrocytes and the expression of CSPG. However, PBM significantly inhibited the expression of GFAP, decreased activation of astrocyte, and downregulated the expression of CSPG by regulating M1 macrophages. These results demonstrate that PBM may regulate the interaction between macrophages and astrocytes after spinal cord injury, which inhibited the formation of glial scar.

LncRNA SNHG1 alleviates hypoxia-reoxygenation-induced vascular endothelial cell injury as a competing endogenous RNA through the HIF-1α/VEGF signal pathway.

Long noncoding ribonucleic acids (lncRNAs) are critical regulators in various biological processes. In the present study, we aimed to explore whether miR140-3p was involved in the underlying molecular mechanisms of small nucleolar RNA host gene 1 (SNHG1) in myocardial ischemia/reperfusion (I/R) injury. A mouse model of I/R injury and hypoxia-reoxygenation (H/R)-stimulated human umbilical vein endothelial cells (HUVECs) was used in this study. Cell proliferation was detected by MTT. The mRNA and protein levels of vascular endothelial growth factor (VEGF), VE-cadherin, and MMP2 were detected by RT-PCR and western blot, respectively. The angiogenesis was assessed by tube formation assay. Cell migration was assessed using wound-healing assay. Results showed that SNHG1 expression was increased in the cardiac microvasculature of a mouse model of I/R injury and in H/R-stimulated HUVECs. H/R stimulation significantly reduced cell proliferation, tube formation, and cell migration, but increased expression of VEGF, VE-cadherin, and MMP2. SNHG1 upregulation under H/R increased HUVECs proliferation, tube formation, and cell migration, and upregulated expression of VEGF, VE-cadherin, and MMP2, compared with the H/R group. SNHG1 knockdown exhibited the opposite effect. SNHG1 functioned as a competing endogenous RNA (ceRNA) of miR-140-3p. HIF-1α was identified as a target of miR-140-3p. SNHG1 upregulation enhanced cell proliferation, tube formation, and expression of VEGF, VE-cadherin, and MMP2 through HIF-1α/VEGF signaling. This process could be offset by miR-140-3p mimic or VEGF inhibitor. Our results reveal a novel protective function of SNHG1 that furthers understanding of cardiac I/R injury and provides experimental evidence for future therapy.

Attenuation of the inflammatory response and polarization of macrophages by photobiomodulation.

In spinal cord injury (SCI), inflammation is a major mediator of damage and loss of function and is regulated primarily by the bone marrow-derived macrophages (BMDMs). Photobiomodulation (PBM) or low-level light stimulation is known to have anti-inflammatory effects and has previously been used in the treatment of SCI, although its precise cellular mechanisms remain unclear. In the present study, the effect of PBM at 810 nm on classically activated BMDMs was evaluated to investigate the mechanisms underlying its anti-inflammatory effects. BMDMs were cultured and irradiated (810 nm, 2 mW/cm2) following stimulation with lipopolysaccharide and interferon-γ. CCK-8 assay, 2',7'-dichlorofluorescein diacetate assay, and ELISA and western blot analysis were performed to measure cell viability, reactive oxygen species production, and inflammatory marker production, respectively. PBM irradiation of classically activated macrophages significantly increased the cell viability and inhibited reactive oxygen species generation. PBM suppressed the expression of a marker of classically activated macrophages, inducible nitric oxide synthase; decreased the mRNA expression and secretion of pro-inflammatory cytokines, tumor necrosis factor alpha, and interleukin-1 beta; and increased the secretion of monocyte chemotactic protein 1. Exposure to PBM likewise significantly reduced the expression and phosphorylation of NF-κB p65 in classically activated BMDMs. Taken together, these results suggest that PBM can successfully modulate inflammation and polarization in classically activated BMDMs. The present study provides a theoretical basis to support wider clinical application of PBM in the treatment of SCI.

Label-free Raman imaging of live osteosarcoma cells with multivariate analysis.

Confocal Raman microspectral imaging (CRMI) is an advanced cell-imaging method that maps endogenous molecular compositions with their unique spectral fingerprint indicators. The aim of this work was to provide a visualized understanding of subcellular features of live osteosarcoma cells using a 532-nm laser excitation without the use of dyes or molecular probes. Both malignant osteoblast and spindle osteosarcoma cells derived from the BALB/c mouse osteosarcoma cell line K7M2 were investigated in this work. After preprocessing the obtained spectral dataset, K-means cluster analysis (KCA) is employed to reconstruct Raman spectroscopic maps of single biological cells by identifying regions of the cellular membrane, cytoplasm, organelles, and nucleus with their corresponding mean spectra. Principal component analysis (PCA) was further employed to indicate variables of significant influence on the separation of the spectra of each cellular component. The biochemical components of the two cell types were then extracted by showing the spectral and distribution features attributed to proteins, lipids, and DNA. Using this standardized CRMI technique and multivariate analysis approaches, the results obtained could be a sound foundation for a typical Raman imaging protocol of live cellular biomedical analysis.

Label-Free Spectral Imaging Unveils Biochemical Mechanisms of Low-Level Laser Therapy on Spinal Cord Injury.

BACKGROUND/AIMS: Low-level laser therapy (LLLT) leads to complex photochemical responses during the healing process of spinal cord injury (SCI). Confocal Raman Microspectral Imaging (in combination with multivariate analysis) was adopted to illustrate the underlying biochemical mechanisms of LLLT treatment on a SCI rat model. METHODS: Using transversal tissue sections, the Raman spectra can identify areas neighboring the injury site, glial scar, cavity, and unharmed white matter, as well as their correlated cellular alterations, such as demyelination and up-regulation of chondroitin sulfate proteoglycans (CSPGs). Multivariate data analysis methods are used to depict the underlying therapeutic effects by highlighting the detailed content and distribution variations of the biochemical constituents. RESULTS: It is confirmed that photon-tissue interactions might lead to a decay of the inhibitory response to remyelination by suppressing CSPG expression, as also morphologically demonstrated by reduced glial scar and cavity areas. An inter-group comparison semi-quantitatively confirms changes in lipids, phosphatidic acid, CSPGs, and cholesterol during SCI and its LLLT treatment, paving the way for in vitro and in vivo understanding of the biochemical changes accompanying pathobiological SCI events. CONCLUSION: The achieved results in this work not only have once again proved the well-known cellular mechanisms of SCI, but further illustrate the underlying biochemical variability during LLLT treatment, which provide a sound basis for developing real-time Raman methodologies to monitor the efficacy of the SCI LLLT treatment.

Addiction of Hypertransformable Pneumococcal Isolates to Natural Transformation for In Vivo Fitness and Virulence.

Natural genetic transformation of Streptococcus pneumoniae, an important human pathogen, mediates horizontal gene transfer for the development of drug resistance, modulation of carriage and virulence traits, and evasion of host immunity. Transformation frequency differs greatly among pneumococcal clinical isolates, but the molecular basis and biological importance of this interstrain variability remain unclear. In this study, we characterized the transformation frequency and other associated phenotypes of 208 S. pneumoniae clinical isolates representing at least 30 serotypes. While the vast majority of these isolates (94.7%) were transformable, the transformation frequency differed by up to 5 orders of magnitude between the least and most transformable isolates. The strain-to-strain differences in transformation frequency were observed among many isolates producing the same capsule types, indicating no general association between transformation frequency and serotype. However, a statistically significant association was observed between the levels of transformation and colonization fitness/virulence in the hypertransformable isolates. Although nontransformable mutants of all the selected hypertransformable isolates were significantly attenuated in colonization fitness and virulence in mouse infection models, such mutants of the strains with relatively low transformability had no or marginal fitness phenotypes under the same experimental settings. This finding strongly suggests that the pneumococci with high transformation capability are "addicted" to a "hypertransformable" state for optimal fitness in the human host. This work has thus provided an intriguing hint for further investigation into how the competence system impacts the fitness, virulence, and other transformation-associated traits of this important human pathogen.

Epothilone B inactivation of Sirtuin1 promotes mitochondrial reactive oxygen species to induce dysfunction and ferroptosis of Schwann cells.

Epothilone B (EpoB) is an FDA-approved anti-neoplastic agent used to treat metastatic breast cancer; However, its usage is limited due to its severe peripheral neurotoxicity. Ferroptosis is a type of programmed cell death triggered by iron accumulation, and it is induced by lipid peroxidation. Ferroptosis has been linked to multiple diseases, including cancer, type 2 diabetes, and neurodegenerative disorders. Here, we assessed the role of ferroptosis in EpoB-induced neural dysfunction. Our results revealed that EpoB induced ferroptosis, which was significantly reduced by the ferroptosis inhibitor Fer-1. In addition, EpoB decreased the mitochondrial membrane potential and the cytochrome c levels in Schwann cells (SCs). The antioxidant MitoTEMPO, which targets the mitochondria, reduced ferroptosis brought on by EpoB. Moreover, we demonstrated that in vivo EpoB-induced myelin degradation and neuronal dysfunction were mitigated by SRT1720, a Sirtuin1 (SIRT1) activator, and by SRT1720 and mitoquinone mesylate (mitoQ). Our results suggest that ferroptosis elicited by EpoB is caused by mitochondrial damage mediated by SIRT1 inactivation and that ferroptosis causes neural dysfunction following EpoB.

Comparing Clinical and Radiographic Outcomes Between the Self-locking Stand-alone Cage and Conventional Cage-plate Construct: A Five-year Retrospective Cohort Study.

STUDY DESIGN/SETTING: A retrospective cohort study. OBJECTIVE: To evaluate the clinical efficacy of the self-locking stand-alone (SA) cage and conventional cage-plate construct (CPC) in treating degenerative cervical spondylosis with a five-year follow-up. SUMMARY OF BACKGROUND DATA: The SA approach was designed to reduce complications associated with traditional anterior cervical discectomy and fusion. These techniques have been shown to have satisfactory short-term clinical outcomes. Literature describing the mid-term clinical outcomes of SA cage is limited. MATERIALS AND METHODS: We retrospectively analyzed patients with cervical spondylosis who had received an SA device or CPC between 2014 and 2016 at the Xijing Hospital. Participants were matched for sex, age, and operative level. Differences in clinical and radiographic outcomes and the occurrence of postoperative complications between the two groups were analyzed. RESULTS: In total, 207 patients were included (101 with SA and 106 with CPC), the median follow-up for both groups were 60.2 and 60.9 months. Both groups exhibited significant improvements in all measured values compared with the preoperative values. The SA group had a shorter operation time, less intraoperative blood loss, and a significantly lower incidence of dysphagia after surgery than the CPC group ( P <0.05). At the last visit, cage subsidence was 6.9% and 3.8% in the SA and CPC groups, respectively ( P =0.365). The radiographic adjacent segment degeneration (ASD) was significantly lower in the SA group than in the CPC group (6.9% vs. 27.4%, P <0.01). No symptomatic ASD was observed in the SA group, and six (5.7%) cases occurred in the CPC group ( P =0.029). CONCLUSIONS: In this study, the SA cage showed similar efficacy to that of the conventional CPC in treating cervical spondylosis using anterior cervical discectomy and fusion, with a significant reduction in the incidence of immediate postoperative dysphagia and mid-term ASD.

A rapid multispectral endoscopic imaging system for in vivo assessment of the morphological and physiological characteristics of mouse intestines.

Accurate assessment of blood content in biological tissues is critical for the diagnosis and monitoring of various diseases, including cardiovascular disease, tumors, trauma, and the success rate of organ transplants. In this study, a multispectral endoscopic imaging system was built for capturing tissue reflection optical images in 18 bands across the wavelength range from 400 nm to 760 nm, non-invasively. The system was characterized by six tri-channel narrowband filters installed in front of the light source to achieve spectral separation and was equipped with a specially designed color CCD for achieving a speed of 24 multispectral imaging cubes per second. A method based on linear matrix inversion was proposed to calibrate the CCD spectral response overlaps, while a spectral analysis algorithm was developed for evaluating blood content and detecting tissue composition. The developed system was implemented in an in vivo mouse model for illustrating the blood volume, blood oxygen saturation index, and scattering particle size of the intestinal wall mucosa. The observations not only helped us to understand the blood supply situation in the intestinal mucosa, but also further testified the feasibility of our presented system. Meanwhile, the developed system could provide critical non-invasive optical information for intracavitary cancer diagnosis, surgery guidance, and treatment assessment.

Potential targets and mechanisms of photobiomodulation for spinal cord injury.

As a classic noninvasive physiotherapy, photobiomodulation, also known as low-level laser therapy, is widely used for the treatment of many diseases and has anti-inflammatory and tissue repair effects. Photobiomodulation has been shown to promote spinal cord injury repair. In our previous study, we found that 810 nm low-level laser therapy reduced the M1 polarization of macrophages and promoted motor function recovery. However, the mechanism underlying this inhibitory effect is not clear. In recent years, transcriptome sequencing analysis has played a critical role in elucidating the progression of diseases. Therefore, in this study, we performed M1 polarization on induced mouse bone marrow macrophages and applied low-level laser therapy. Our sequencing results showed the differential gene expression profile of photobiomodulation regulating macrophage polarization. We analyzed these genes using gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Networks of protein-protein interactions and competing RNA endogenous networks were constructed. We found that photobiomodulation inhibited STAT3 expression through increasing the expression of miR-330-5p, and that miR-330-5p binding to STAT3 inhibited STAT3 expression. Inducible nitric oxide synthase showed trends in changes similar to the changes in STAT3 expression. Finally, we treated a mouse model of spinal cord injury using photobiomodulation and confirmed that photobiomodulation reduced inducible nitric oxide synthase and STAT3 expression and promoted motor function recovery in spinal cord injury mice. These findings suggest that STAT3 may be a potential target of photobiomodulation, and the miR-330-5p/STAT3 pathway is a possible mechanism by which photobiomodulation has its biological effects.

Photobiomodulation augments the effects of mitochondrial transplantation in the treatment of spinal cord injury in rats by facilitating mitochondrial transfer to neurons via Connexin 36.

Mitochondrial transplantation is a promising treatment for spinal cord injury (SCI), but it has the disadvantage of low efficiency of mitochondrial transfer to targeted cells. Here, we demonstrated that Photobiomodulation (PBM) could promote the transfer process, thus augmenting the therapeutic effect of mitochondrial transplantation. In vivo experiments, motor function recovery, tissue repair, and neuronal apoptosis were evaluated in different treatment groups. Under the premise of mitochondrial transplantation, the expression of Connex36 (Cx36), the trend of mitochondria transferred to neurons, and its downstream effects, such as ATP production and antioxidant capacity, were evaluated after PBM intervention. In in vitro experiments, dorsal root ganglia (DRG) were cotreated with PBM and 18ß-GA (a Cx36 inhibitor). In vivo experiments showed that PBM combined with mitochondrial transplantation could increase ATP production and reduce oxidative stress and neuronal apoptosis levels, thereby promoting tissue repair and motor function recovery. In vitro experiments further verified that Cx36 mediated the transfer of mitochondria into neurons. PBM could facilitate this progress via Cx36 both in vivo and in vitro. The present study reports a potential method of using PBM to facilitate the transfer of mitochondria to neurons for the treatment of SCI.

Correlative increasing expressions of KIF5b and Nav1.7 in DRG neurons of rats under neuropathic pain conditions.

Nav1.7, one of tetrodotoxin-sensitive voltage-gated sodium channels, mainly expressed in the small diameter dorsal root ganglion (DRG) neurons. The expression and accumulation on neuronal membrane of Nav1.7 increased following peripheral tissue inflammation or nerve injury. However, the mechanisms for membrane accumulation of Nav1.7 remained unclear. We report that KIF5b, a highly expressed member of the kinesin-1 family in DRGs, promoted the translocation of Nav1.7 to the plasma membrane in DRG neurons of the rat. Following nociceptive behaviors in rats induced by peripheral spared nerve injury (SNI), synchronously increased KIF5b and Nav1.7 expressions were observed in DRGs. Immunohistochemistry staining demonstrated the co-expressions of KIF5b and Nav1.7 in the same DRG neurons. Immunoprecipitation experiments further confirmed the interactions between KIF5b and Nav1.7. Moreover, intrathecal injections of KIF5b shRNA moderated the SNI-induced both mechanical and thermal hyperalgesia. The rescued analgesic effects also alleviated SNI-induced anxiety-like behaviors. In sum, KIF5b was required for the membrane localizations of Nav1.7, which suggests a novel mechanism for the trafficking of Nav1.7 involved in neuropathic pain.

Photobiomodulation reduces neuropathic pain after spinal cord injury by downregulating CXCL10 expression.

BACKGROUND: Many studies have recently highlighted the role of photobiomodulation (PBM) in neuropathic pain (NP) relief after spinal cord injury (SCI), suggesting that it may be an effective way to relieve NP after SCI. However, the underlying mechanisms remain unclear. This study aimed to determine the potential mechanisms of PBM in NP relief after SCI. METHODS: We performed systematic observations and investigated the mechanism of PBM intervention in NP in rats after SCI. Using transcriptome sequencing, we screened CXCL10 as a possible target molecule for PBM intervention and validated the results in rat tissues using reverse transcription-polymerase chain reaction and western blotting. Using immunofluorescence co-labeling, astrocytes and microglia were identified as the cells responsible for CXCL10 expression. The involvement of the NF-κB pathway in CXCL10 expression was verified using inhibitor pyrrolidine dithiocarbamate (PDTC) and agonist phorbol-12-myristate-13-acetate (PMA), which were further validated by an in vivo injection experiment. RESULTS: Here, we demonstrated that PBM therapy led to an improvement in NP relative behaviors post-SCI, inhibited the activation of microglia and astrocytes, and decreased the expression level of CXCL10 in glial cells, which was accompanied by mediation of the NF-κB signaling pathway. Photobiomodulation inhibit the activation of the NF-κB pathway and reduce downstream CXCL10 expression. The NF-κB pathway inhibitor PDTC had the same effect as PBM on improving pain in animals with SCI, and the NF-κB pathway promoter PMA could reverse the beneficial effect of PBM. CONCLUSIONS: Our results provide new insights into the mechanisms by which PBM alleviates NP after SCI. We demonstrated that PBM significantly inhibited the activation of microglia and astrocytes and decreased the expression level of CXCL10. These effects appear to be related to the NF-κB signaling pathway. Taken together, our study provides evidence that PBM could be a potentially effective therapy for NP after SCI, CXCL10 and NF-kB signaling pathways might be critical factors in pain relief mediated by PBM after SCI.