Combined effect of Cerium oxide nanoparticles loaded scaffold and photobiomodulation therapy on pain and neuronal regeneration following spinal cord injury: an experimental study.

BACKGROUND: Spinal cord injury (SCI) remained one of the challenges to treat due to its complicated mechanisms. Photobiomodulation therapy (PBMT) accelerates neuronal regeneration. Cerium oxide nanoparticles (CeONPs) also eliminate free radicals in the environment. The present study aims to introduce a combined treatment method of making PCL scaffolds as microenvironments, seeded with CeONPs and the PBMT technique for SCI treatment. METHODS: The surgical hemi-section was used to induce SCI. Immediately after the SCI induction, the scaffold (Sc) was loaded with CeONPs implanted. PBMT began 30 min after SCI induction and lasted for up to 4 weeks. Fifty-six male rats were randomly divided into seven groups. Glial fibrillary acidic protein (GFAP) (an astrocyte marker), Connexin 43 (Con43) (a member of the gap junction), and gap junctions (GJ) (a marker for the transfer of ions and small molecules) expressions were evaluated. The behavioral evaluation was performed by BBB, Acetone, Von Frey, and radiant heat tests. RESULT: The SC + Nano + PBMT group exhibited the most remarkable recovery outcomes. Thermal hyperalgesia responses were mitigated, with the combined approach displaying the most effective relief. Mechanical allodynia and cold allodynia responses were also attenuated by treatments, demonstrating potential pain management benefits. CONCLUSION: These findings highlight the potential of PBMT, combined with CeONPs-loaded scaffolds, in promoting functional motor recovery and alleviating pain-related responses following SCI. The study underscores the intricate interplay between various interventions and their cumulative effects, informing future research directions for enhancing neural repair and pain management strategies in SCI contexts.

Systemic vascular photobiomodulation accelerates the recovery of motor activity in rats following spinal cord injury.

OBJECTIVES: Spinal cord injury (SCI) causes the discontinuity of the spinal canal, leading to functional and sensorial losses in areas below the injury, which are often irreversible. Photobiomodulation (PBM) can enhance the neuromuscular repair process, especially in cases of peripheral nerve injuries. However, there is little knowledge regarding the effects of this therapeutic modality on recovery following a SCI, especially the noninvasive systemic form denominated vascular PBM (VPBM). To analyze the effects of VPBM in the immediate, acute and intermediate phases following a compression-induced SCI on morphological aspects of neuromuscular tissue repair, functional recovery and the protein expression of brain-derived neurotrophic factor (BDNF). METHODS: Wistar rats were divided into five groups: control, SCI, SCI + VPBM-Im (immediate administration of VPBM), SCI + VPBM-2h (VPBM administered 2 h after injury) and SCI + VPBM-14d (VPBM administered 14 days after injury). VPBM was administered in the region of the caudal vein/artery with low-level laser (AsGaAl, 780 nm, 80 J/cm², 40 mW for 80 s, totaling an energy of 3.2 J over a single point) for 14 consecutive days. During the analysis periods (1, 3, 7, 14, 21, 28 and 35 days after injury), functioning was evaluated using the Basso-Beattie-Bresnahan (BBB) index. At the end of each experimental period, blood samples were collected for the determination of the concentration of circulating BDNF using ELISA. Muscle tissue and nerve tissue samples were also extracted for morphological and histological analyses using H&E staining. RESULTS: SCI + VPBM-Im and SCI + VPBM-2 h led to the recovery of motor function beginning on the 7th day after injury (p < 0.05), an increase in the cross-sectional area (CSA) of the muscle fibers in the second week (p < 0.05) and an increase in muscle fiber diameter beginning on Day 14 (p < 0.05). Early irradiation had a greater effect on the reduction in the size of the cavity, with stabilization of the cavity found on Day 7 (p < 0.05). Considering the circulating BDNF levels, no changes was found during the experimental periods. CONCLUSION: The present results showed that VPBM was capable of modulating morphological and functional recovery following SCI, especially when administered early. The positive effects on functional recovery were demonstrated by the BBB index; the reestablishment of the structure of the muscle and nerve tissue was demonstrated by the preservation of CSA and diameter of muscle fiber and reduction in the area of the injury (cavity size) respectively. Thus, noninvasive VPBM may be an important component of treatment for spinal cord injuries.

Effect and mechanism of terahertz irradiation in repairing spinal cord injury in mice.

SIGNIFICANCE: Spinal cord injury (SCI) represents a serious trauma to the central nervous system. Terahertz (THz) irradiation is an emerging technique, it has potential application prospects in the treatment of central nervous system diseases. AIM: We report on the investigation of the effect and mechanism of THz irradiation in repairing SCI in mice. APPROACH: The effect of THz in SCI was evaluated by the expression of inflammatory factors, the mouse behavioral scale (BMS), and immunofluorescence staining. After RNA sequencing (RNA-seq), we determined the differentially expressed genes (DEGs) and performed GO and KEGG analysis. RESULTS: After THz irradiation, the inflammatory response, the behavioral function, and the severity of SCI recovered well, indicating that THz irradiation can effectively promote the repair of SCI. GO and KEGG results show that genes related to inflammation, immune regulation, and IL-17 signaling pathway may play an important role in this process. CONCLUSIONS: THz irradiation can effectively promote the repair of SCI. Genes related to inflammation, immune regulation, and IL-17 signaling pathway may play an important role in this process.

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.

Optimization of the Duration and Dose of Photobiomodulation Therapy (660 nm Laser) for Spinal Cord Injury in Rats.

Objective: Spinal cord injury (SCI) causes motor deficits, urinary incontinence, and neuropathic pain. This study was designed to optimize a photobiomodulation therapy (PBMT) protocol using a continuous wave (CW) 660 nm laser in rats with SCI. Specifically, the number of days of irradiation and the daily dose of PBMT were investigated. Methods: The study was performed in two steps. In the first step, a comparison between the effects of PBMT (45 sec) daily for 2 and 4 weeks on pain and movement [Basso, Beattie, and Brenham (BBB) score] was made. In the second step, a comparison between different durations of irradiation (27, 45, 90, and 117 sec) was performed. PBMT used a 100 mW laser delivered to 9 points on and around the lesion site. Oxidative stress, fibroblast invasion, and time to achieve spontaneous urination were also assessed. Results: The improvement in movement and pain stopped with discontinuation of radiation at week 2 and fibroblast invasion resumed. No improvement was seen in movement and pain in the group receiving PBMT for 27 sec compared with the groups receiving higher doses of laser radiation. Animals receiving 117 sec of photobiomodulation showed a higher BBB score even in the first 3 days. Conclusions: The number of days is an important factor for improving mobility; however, the daily dose of radiation is more important for pain relief.

Photobiomodulation Attenuates Neurotoxic Polarization of Macrophages by Inhibiting the Notch1-HIF-1α/NF-κB Signalling Pathway in Mice With Spinal Cord Injury.

Spinal cord injury (SCI) is a catastrophic disease with a complex pathogenesis that includes inflammation, oxidative stress, and glial scar formation. Macrophages are the main mediators of the inflammatory response and are distributed in the epicentre of the SCI. Macrophages have neurotoxic and neuroprotective phenotypes (also known as classically and alternatively activated macrophages or M1 and M2 macrophages) that are associated with pro- or anti- inflammatory gene expression. Our previous study demonstrated that photobiomodulation (PBM) alters the polarization state of macrophages in the SCI region towards the M2 phenotype and promotes the recovery of motor function in rats with SCI. However, the mechanism by which PBM promotes SCI repair remains largely undefined. This study is based on the replacement of conventional percutaneous irradiation with implantable biofibre optic in vivo irradiation. The aim was to further investigate the effects of PBM on SCI in mice under new irradiation patterns and its potential mechanisms of action. PBM was administered to male mice with clamped SCI for four consecutive weeks and significantly promoted the recovery of motor function in mice. Analysis of the macrophage phenotypes in the epicentre of the SCI in mice showed that PBM mainly inhibited the neurotoxic activation of macrophages in the SCI area and reduced the secretion of inflammatory factors such as IL-1α and IL-6; PBM had no effect on M2 macrophages. Immediately afterwards, we constructed in vitro models of the inflammatory polarization of macrophages and PBM intervention. We found that PBM attenuated the neurotoxicity of M1 macrophages on VSC 4.1 motor neurons and dorsal root ganglion (DRG) neurons. The effects of PBM on neurotoxic macrophages and the possible mechanisms of action were analysed using RNA sequencing (RNA-seq), which confirmed that the main role of PBM was to modulate the inflammatory response and immune system processes. Analysis of the differentially expressed genes (DEGs) associated with the inflammatory response showed that PBM had the most significant regulatory effects on genes such as interleukin (IL)-1α, IL-6, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) and had obvious inhibitory effects on inflammation-related Notch1 and hypoxia-inducible factor-1α (HIF-1α) pathway genes. RNA-seq analysis of the effect of PBM on gene expression in resting-state macrophages and M2 macrophages did not show significant differences (data not shown). In conclusion, PBM promoted better motor recovery after SCI in mice by inhibiting the neurotoxic polarization of macrophages and the release of inflammatory mediators by acting on the Notch1-HIF-1α/NF-κB Signalling Pathway.

Effects of photobiomodulation in experimental spinal cord injury models: A systematic review.

This systematic review investigated the repercussions of photobiomodulation using low-level laser therapy (LLLT) for the treatment of spinal cord injury (SCI) in experimental models. Studies were identified from relevant databases published between January 2009 and December 2021. Nineteen original articles were selected and 68.4% used light at an infrared wavelength. There was a considerable variation of the power used (from 25 to 200 mW), total application time (8-3000 s) and total energy (0.3-450 J). In 79% of the studies, irradiation was initiated immediately after or within 2 h of the SCI, and treatment time ranged continuously from 5 to 21 days. In conclusion, LLLT can be an auxiliary therapy in the treatment of SCI, playing a neuroprotective role, enabling functional recovery, increasing the concentration of nerve connections around the injury site and reducing pro-inflammatory cytokines. However, there is a need for standardization in the dosimetric parameters.

X-ray Irradiation Improves Neurological Function Recovery of Injured Spinal Cord by Inhibiting Inflammation and Glial Scar Formation.

Spinal cord injury (SCI) is a common clinical disease that can cause permanent disruption of nerve function. Inflammation and glial scar formation influence the recovery of injured spinal cord. X-ray irradiation can reduce inflammation, inhibit cell proliferation and increase cell apoptosis. However, the regulatory effects of X-ray irradiation on inflammation and glial scars and the underlying molecular mechanisms are still unclear. This study was aimed to investigate the therapeutic effect and molecular mechanism of X-ray irradiation on spinal cord injury. Behavioural experiments showed that X-ray irradiation can promote the recovery of nerve function after SCI. X-ray irradiation inhibited the inflammatory response by reducing the expression of inflammatory factors (TNF-α and IL-1ß) at the lesion site, thereby reducing neuronal apoptosis. X-ray irradiation inhibited the formation of the glial scar (GFAP and vimentin) in the lesion. P38MAPK and Akt signalling pathways were involved in these processes. Furthermore, the 10 Gy dose had the most significant effects among the 2 Gy, 10 Gy and 20 Gy doses. In summary, X-ray irradiation may exert an active therapeutic effect on SCI by inhibiting inflammation and glial scar formation, which may be related to the inhibition of p38MAPK and Akt signalling pathways.

The effect of low-level laser therapy on pathophysiology and locomotor recovery after traumatic spinal cord injuries: a systematic review and meta-analysis.

This study was designed to determine the effective therapeutic parameters and evaluate the regenerative potential of low-level laser therapy (LLLT) after traumatic spinal cord injuries (TSCIs) in animal studies. The EMBASE and MEDLINE databases were searched on October 5, 2019, and followed with an update on January 2, 2021. All animal studies discussing the effect of LLLT on main pathophysiological events after TSCI, including inflammation, axon growth, remyelination, glial scar formation, cavity size, and locomotor recovery, were included. For statistical analysis, we used mean difference with 95% confidence intervals for locomotor recovery. In total, 19 articles were included based on our criteria. The results showed that regardless of laser type, laser beams with a wavelength between 600 and 850 nm significantly suppress inflammation and led inflammatory cells to M2 polarization and wound healing. Also, laser therapy using these wavelengths for more than 2 weeks significantly improved axon regeneration and remyelination. Improvement of locomotor recovery was more efficient using wavelengths less than 700 nm (SMD = 1.21; 95%CI: 0.09, 2.33; p = 0.03), lasers with energy densities less than 100 J/cm2 (SMD = 1.72; 95%CI: 0.84, 2.59; p = 0.0001) and treatment duration between 1 and 2 weeks (SMD = 2.21; 95%CI: 1.24, 3.19; p < 0.00001). The LLLT showed promising potential to modulate pathophysiological events and recovery after TSCI, although there was heterogeneity in study design and reporting methods, which should be considered in future studies.

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.

Sensitization of Endothelial Cells to Ionizing Radiation Exacerbates Delayed Radiation Myelopathy in Mice.

Delayed radiation myelopathy is a rare, but significant late side effect from radiation therapy that can lead to paralysis. The cellular and molecular mechanisms leading to delayed radiation myelopathy are not completely understood but may be a consequence of damage to oligodendrocyte progenitor cells and vascular endothelial cells. Here, we aimed to determine the contribution of endothelial cell damage to the development of radiation-induced spinal cord injury using a genetically defined mouse model in which endothelial cells are sensitized to radiation due to loss of the tumor suppressor p53. Tie2Cre; p53FL/+ and Tie2Cre; p53FL/- mice, which lack one and both alleles of p53 in endothelial cells, respectively, were treated with focal irradiation that specifically targeted the lumbosacral region of the spinal cord. The development of hindlimb paralysis was followed for up to 18 weeks after either a 26.7 Gy or 28.4 Gy dose of radiation. During 18 weeks of follow-up, 83% and 100% of Tie2Cre; p53FL/- mice developed hindlimb paralysis after 26.7 and 28.4 Gy, respectively. In contrast, during this period only 8% of Tie2Cre; p53FL/+ mice exhibited paralysis after 28.4 Gy. In addition, 8 weeks after 28.4 Gy the irradiated spinal cord from Tie2Cre; p53FL/- mice showed a significantly higher fractional area positive for the neurological injury marker glial fibrillary acidic protein (GFAP) compared with the irradiated spinal cord from Tie2Cre; p53FL/+ mice. Together, our findings show that deletion of p53 in endothelial cells sensitizes mice to the development of delayed radiation myelopathy indicating that endothelial cells are a critical cellular target of radiation that regulates myelopathy.

Photobiomodulation therapy improved functional recovery and overexpression of interleukins-10 after contusion spinal cord injury in rats.

Following severe Spinal Cord Injury (SCI), regeneration is inadequate, and functional recovery is incomplete. The occurrence of oxidative stress and the spread of inflammation play a crucial role in the failure to regenerate the injury site. In this way, we explored the neuroprotective effects of PhotoBioModulation (PBM), as the main factor in controlling these two destructive factors, on SCI. fifty-four female adult Wistar rats divided into three groups: sham group (just eliminate vertebra lamina, n = 18), SCI group (n = 18), and SCI-PBM group which exposed to PBM (150 MW, 50 min/day, 14 days, n = 18). After SCI induction at the endpoint of the study (the end of 8 week), we took tissue samples from the spinal cord for evaluating the biochemical profiles that include Catalase (CAT), Malondialdehyde (MDA), Superoxide Dismutase (SOD), Glutathione Peroxidase (GSH-PX) levels, immunohistochemistry for Caspase-3, gene expressions of Interleukin-1ß (IL-1ß), Tumor Necrosis Factor-alpha (TNF-α), and Interleukin (IL-10). Also, stereological assessments evaluated the spinal cord, central cavity volumes, and numerical density of the glial and neural cells in the traumatic area. The open-field test, rotarod test, Narrow Beam Test (NBT), Electromyography recording (EMG) test and the Basso-Beattie-Bresnehan (BBB) evaluated the neurological functions. Our results showed that the stereological parameters, biochemical profiles (except MDA), and neurological functions were markedly greater in the SCI-PBM group in comparison with SCI group. The transcript for the IL-10 gene was seriously upregulated in the SCI-PBM group compared to the SCI group. This is while gene expression of TNF-α and IL-1ß, also density of apoptosis cells in Caspase-3 evaluation decreased significantly more in the SCI-PBM group compared to the SCI group. Overall, using PBM treatment immediately after SCI has neuroprotective effects by controlling oxidative stress and inflammation and preventing the spread of damage.

Effects of photobiomodulation combined with MSCs transplantation on the repair of spinal cord injury in rat.

Stem cell transplantation has shown promising regenerative effects against neural injury, and photobiomodulation (PBM) can aid tissue recovery. This study aims to evaluate the therapeutic effect of human umbilical cord mesenchymal stem cells (hUCMSCs) and laser alone or combined on spinal cord injury (SCI). The animals were divided into SCI, hUCMSCs, laser treatment (LASER) and combination treatment (hUCMSCs + LASER) groups. Cell-enriched grafts of hUCMSCs (1 × 106 cells/ml) were injected at the site of antecedent trauma in SCI model rats. A 2 cm2 damaged area was irradiated with 630 nm laser at 100 mW/cm2 power for 20 min. Locomotion was evaluated using Basso-Beattie-Bresnahan (BBB) scores, and neurofilament repair were monitored by histological staining and diffusion tensor imaging (DTI). First, after SCI, the motor function of each group was restored with different degrees, the combination treatment significantly increased the BBB scores compared to either monotherapy. In addition, Nissl bodies were more numerous, and the nerve fibers were longer and thicker in the combination treatment group. Consistent with this, the in situ expression of NF-200 and glial fibrillary acidic protein in the damaged area was the highest in the combination treatment group. Finally, DTI showed that the combination therapy optimally improved neurofilament structure and arrangement. These results may show that the combination of PBM and hUCMSCs transplantation is a feasible strategy for reducing secondary damage and promoting functional recovery following SCI.

Effects of Irradiation Parameters and Position on Photobiomodulation Therapy for Spinal Cord Injury Rat Phantom Model: A Dosimetry Simulation Study.

Objective: To optimize photobiomodulation therapy (PBMT) for spinal cord injury (SCI) by studying the effect(s) of irradiation parameters and position of PBMT on injury site using Monte Carlo simulation and a three-dimensional voxelated SCI rat phantom model. Background: Several studies used a range of irradiation parameters and surface irradiances to calculate the fluence delivered to the SCI site. However, most have ignored factors such as the optical properties of tissues, irradiation parameters, and position. Therefore, although such studies present a broad range of treatment outcomes, a comparison of the treatment efficacy concerning the applied fluence using these studies presents certain challenges Methods: In this study, an 810 nm top-hat beam was simulated for 5 numerical apertures (NAs; 0.0, 0.2, 0.4, 0.6, and 0.8), 10 beam radii (0.001, 0.01, 0.1, 0.25, 0.5, 1, 2.5, 5, 10, and 25 mm), and 17 different irradiation positions relative to the SCI site. Results: The beam radius and position strongly affect the accumulated fluence within the injury site, whereas the NA appears to have a smaller effect on the accumulated fluence within the injury site. A large probe beam produces a uniform fluence distribution reaching the injury site, minimizing the effect of misplacing the probe at the center of the injury. Conclusions: Our findings will be beneficial to understanding the effects of irradiation parameters on tissues and organs, which will help reduce variability in the fluence applied to injury sites and will help optimize PBMT outcomes.

Photobiomodulation for spinal cord injury: A systematic review and meta-analysis.

In recent years, photobiomodulation therapy (PBMT) has found many applications in various medical fields. Studies of PBMT on spinal cord injury (SCI) have mostly used laser sources in experimental animal models. The purpose of this study was to summarize studies that have employed PBMT for various kinds of SCI in animals. A thorough search in databases including MEDLINE, EMBASE, SCOPUS, and Web of Science, with the removal of unrelated articles, yielded 16 relevant articles. The meta-analysis showed that PBMT was effective in improving post-SCI movement in the first 14 days (MD = 1.593 (95% CI: 1.110 to 2.075; p <0.001, I2 = 51.9%) and this improvement became even greater thereafter (MD = 2.086 (95% CI: 1.570 to 2.603; p = <0.001. I2= 90.3%). Time of irradiation (<300 sec or >300 sec), gender (male or female), injury model (contusion or compression, radiation protocol (<14 days or ≥14days), laser wavelength (<800nm or >800nm) and injury severity (moderate or severe) were found to be factors that can affect PBM efficacy for SCI treatment. PBMT has an anti-inflammatory effect, is effective in reducing the size of spinal cord lesions and helps to absorb administrated proteins and stem cells to the lesion site.

Sensory and motor responses after photobiomodulation associated with physiotherapy in patients with incomplete spinal cord injury: clinical, randomized trial.

Complete or incomplete spinal cord injury (SCI) results in permanent neurological deficits due to the interruption of nerve impulses, causing the loss of motor and sensory function, which leads to a reduction in quality of life. The focus of rehabilitation for such individuals is to improve quality of life and promote functional recovery. Photobiomodulation (PBM) has proved to be promising complementary treatment in cases of SCI. The aim of the present study was to investigate the effects of PBM combined with physiotherapy on sensory-motor responses below the level of the injury and quality of life in individuals with SCI. Thirty participants were randomized for allocation to the PBM group (active PBM + physiotherapy) or sham group (sham PBM + physiotherapy). Physiotherapy was administered three times a week. Sensitivity and motor skills were evaluated using the ASIA impairment scale. Quality of life was assessed using the WHOQOL-BREF questionnaire. The data were analyzed with the level of significance set to 5%. Improvements in sensitivity and an increase in the perception of muscle contraction were found in the active PBM group 30 days after treatment compared with the sham group. The results of the WHOQOL-BREF questionnaire revealed a significant difference in general quality of life favoring the active PBM group over the sham group after treatment. Physiotherapy combined with PBM leads to better sensory-motor recovery in patients with SCI as well as a better perception of health and quality of life. Trial registration identifier: NCT03031223.

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.

Photobiomodulation by diffusing optical fiber on spinal cord: A feasibility study in piglet model.

Previous studies on spinal cord injury (SCI) have confirmed that percutaneous photobiomodulation (PBM) therapy can ameliorate immunoinflammatory responses at sites of injury, accelerate nerve regeneration, suppress glial scar formation and promote the subsequent recovery of locomotor function. The current study was performed to evaluate a large-animal model employing implanted optical fibers to accurately irradiate targeted spinal segments. The method's feasibility and irradiation parameters that do not cause phototoxic reaction were determined, and the methodology of irradiating the spinal cord with near-infrared light was investigated in detail. A diffusing optical fiber was implanted above the T9 spinal cord of Bama miniature pigs and used to transfer near-infrared light (810 nm) onto the spinal cord surface. After daily irradiation with 200, 300, 500 or 1000 mW for 14 days, both sides of the irradiated area of the spinal cord were assessed for temperature changes. The condition of the spinal cord and the position of optical fiber were investigated by magnetic resonance imaging (MRI), and different parameters indicating temperature increases or phototoxicity were measured on the normal spinal cord surface due to light irradiation (ie, heat shock responses, inflammatory reactions and neuronal apoptosis), and the animals' lower-limb neurological function and gait were assessed during the irradiation process. The implanted device was stable inside the freely moving animals, and light energy could be directly projected onto the spinal cord surface. The screening of different irradiation parameters preliminary showed that direct irradiation onto the spinal cord surface at 200 and 300 mW did not significantly increase the temperature, stress responses, inflammatory reactions and neural apoptosis, whereas irradiation at 500 mW slightly increased these parameters, and irradiation at 1000 mW induced a significant temperature increase, heat shock, inflammation and apoptosis responses. HE staining of spinal cord tissue sections did not reveal any significant structural changes of the tissues compared to the control group, and the neurological function and gait of all irradiated animals were normal. In this study, we established an in-vivo optical fiber implantation method, which might be safe and stable and could be used to directly project light energy onto the spinal cord surface. This study might provide a new perspective for clinical applications of PBM in acute SCI.

Sensory-motor and cardiorespiratory sensory rehabilitation associated with transcranial photobiomodulation in patients with central nervous system injury: Trial protocol for a single-center, randomized, double-blind, and controlled clinical trial.

BACKGROUND: Central nervous system diseases such as stroke, spinal cord injury, traumatic brain injury, and multiple sclerosis can be fatal or cause sequelae, affecting sensorimotor and cardiorespiratory systems and quality of life. These subjects present a low response to aerobic and resistance exercise, due to decreased recruitment of muscle fibers and reduction of metabolic capacity. Aerobic exercises bring benefits in terms of fatigue retardation, gait improvement, regulation of the autonomic nervous system, neuroprotection of the brain, stimulation of the production of endogenous neutrotransmitters related to general well-being, and a favoring of neuroplasticity. Photobiomodulation (PBM Therapy) (previously known as low-level laser therapy), and especially transcranial PBM Therapy, has shown benefits in animals and humans such as cognitive improvement, memory, and behavioral improvement, including attenuation of depression and anxiety, and increased cortical oxygenation. The aims of this trial will be to evaluate the parameters related to the function of the musculoskeletal and cardiorespiratory system and the impact of PBM therapy on these parameters, as part of a rehabilitation and training program for people with reduced mobility. METHODS: This is a randomized, double-blind, placebo-controlled trial with 3 groups: Control, only cardiorespiratory rehabilitation (CCR), CCR with PBM Therapy (CR-PBM), CCR and placebo PBM Therapy (CR-PlaceboPBM). n = 90, 30 per group. PBM Therapy parameters: 810 nm laser, 0.028 cm, 100 mW, 3.5 W/cm, 30 seconds per point, 3 J per point, 107.1 J /cm to 3 electroencephalogram points F7 and F8 and AFz. The trial will be conducted at the University Clinics and the sessions will be 1 hour twice a week for 9 weeks. Baseline, intermediate (4th week), final (9th week), and 2-month follow-up will be performed. Muscular activation, heart rate variability, lung volumes and capacities, fatigability, exercise tolerance, cognition, and quality of life at baseline will be evaluated. Subsequent to baseline evaluations, the PBM Therapy groups will be offered laser therapy (active or inactive); all groups will then receive CCR. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov ID - NCT03751306 (approval date: November 22, 2018).

Spinal cord detection in planning CT for radiotherapy through adaptive template matching, IMSLIC and convolutional neural networks.

BACKGROUND AND OBJECTIVE: The spinal cord is a very important organ that must be protected in treatments of radiotherapy (RT), considered an organ at risk (OAR). Excess rays associated with the spinal cord can cause irreversible diseases in patients who are undergoing radiotherapy. For the planning of treatments with RT, computed tomography (CT) scans are commonly used to delimit the OARs and to analyze the impact of rays in these organs. Delimiting these OARs take a lot of time from medical specialists, plus the fact that involves a large team of professionals. Moreover, this task made slice-by-slice becomes an exhaustive and consequently subject to errors, especially in organs such as the spinal cord, which extend through several slices of the CT and requires precise segmentation. Thus, we propose, in this work, a computational methodology capable of detecting spinal cord in planning CT images. METHODS: The techniques highlighted in this methodology are adaptive template matching for initial segmentation, intrinsic manifold simple linear iterative clustering (IMSLIC) for candidate segmentation and convolutional neural networks (CNN) for candidate classification, that consists of four steps: (1) images acquisition, (2) initial segmentation, (3) candidates segmentation and (4) candidates classification. RESULTS: The methodology was applied on 36 planning CT images provided by The Cancer Imaging Archive, and achieved an accuracy of 92.55%, specificity of 92.87% and sensitivity of 89.23% with 0.065 of false positives per images, without any false positives reduction technique, in detection of spinal cord. CONCLUSIONS: It is demonstrated the feasibility of the analysis of planning CT images using IMSLIC and convolutional neural network techniques to achieve success in detection of spinal cord regions.