808 nm Wavelength Light Induces a Dose‐<scp>D</scp>ependent Alteration in Microglial Polarization and Resultant Microglial Induced Neurite Growth

Leden, Ramona E. von; Cooney, Sean J.; Ferrara, Teresa M.; Zhao, Yujia; Dalgard, Clifton L.; Anders, Juanita J.; Byrnes, Kimberly R.

doi:10.1002/lsm.22133

Cited by 48 publications

(47 citation statements)

References 35 publications

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“…While others have demonstrated the impact of wavelength and dose on inflammatory cells in vitro [37, 53], to our knowledge, we are the first to demonstrate the effect of 670 nm light on the polarization of activated microglia/macrophages following spinal cord injury in vivo. The pattern and sequence of pro-inflammatory M1 (CD80 + ED1 + ) cell activation, cell death, followed by anti-inflammatory/wound-healing M2 (Arginase1 + ED1 + ) recruitment observed in sham-treated animals in our study is consistent with what is expected under conditions of spinal cord injury and repair [30, 31].…”

Section: Discussionmentioning

confidence: 70%

“…However, wavelength (i.e. 660 vs. 780 nm) has been shown to alter the expression of inflammatory mediators expressed by activated pro-inflammatory microglia/macrophages [37], and light dosage has been shown to alter the balance of M1/M2 cell expression [53]. These in vitro studies suggest that other mechanisms, unrelated to cytochrome C oxidase, may influence the inflammatory microenvironment following light treatment.…”

Section: Discussionmentioning

confidence: 99%

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Red LED photobiomodulation reduces pain hypersensitivity and improves sensorimotor function following mild T10 hemicontusion spinal cord injury

Zhu

Potas

2016

J Neuroinflammation

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BackgroundThe development of hypersensitivity following spinal cord injury can result in incurable persistent neuropathic pain. Our objective was to examine the effect of red light therapy on the development of hypersensitivity and sensorimotor function, as well as on microglia/macrophage subpopulations following spinal cord injury.MethodsWistar rats were treated (or sham treated) daily for 30 min with an LED red (670 nm) light source (35 mW/cm2), transcutaneously applied to the dorsal surface, following a mild T10 hemicontusion injury (or sham injury). The development of hypersensitivity was assessed and sensorimotor function established using locomotor recovery and electrophysiology of dorsal column pathways. Immunohistochemistry and TUNEL were performed to examine cellular changes in the spinal cord.ResultsWe demonstrate that red light penetrates through the entire rat spinal cord and significantly reduces signs of hypersensitivity following a mild T10 hemicontusion spinal cord injury. This is accompanied with improved dorsal column pathway functional integrity and locomotor recovery. The functional improvements were preceded by a significant reduction of dying (TUNEL+) cells and activated microglia/macrophages (ED1+) in the spinal cord. The remaining activated microglia/macrophages were predominantly of the anti-inflammatory/wound-healing subpopulation (Arginase1+ED1+) which were expressed early, and up to sevenfold greater than that found in sham-treated animals.ConclusionsThese findings demonstrate that a simple yet inexpensive treatment regime of red light reduces the development of hypersensitivity along with sensorimotor improvements following spinal cord injury and may therefore offer new hope for a currently treatment-resistant pain condition.

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Section: Discussionmentioning

confidence: 70%

Section: Discussionmentioning

confidence: 99%

Red LED photobiomodulation reduces pain hypersensitivity and improves sensorimotor function following mild T10 hemicontusion spinal cord injury

Zhu

Potas

2016

J Neuroinflammation

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“…The effects of PBM on macrophage phenotypes are beginning to be described in cell cultures studies,10, 30, 31, 32, 33, 34 evidencing that this therapeutic modality, especially using the NIR wavelength, is capable of altering the polarization of these cells in vitro. In vivo experiments have demonstrated that PBM (808 nm) can shift the phenotype of brain microglial polarization from the pro‐inflammatory phenotype (M1) to the anti‐inflammatory (M2) phenotype after ischemic stroke, promoting cortical neurogenesis 35.…”

Section: Discussionmentioning

confidence: 99%

Photobiomodulation and different macrophages phenotypes during muscle tissue repair

Souza

Mesquita‐Ferrari

Rodrigues

et al. 2018

J Cellular Molecular Medi

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Macrophages play a very important role in the conduction of several regenerative processes mainly due to their plasticity and multiple functions. In the muscle repair process, while M1 macrophages regulate the inflammatory and proliferative phases, M2 (anti‐inflammatory) macrophages direct the differentiation and remodelling phases, leading to tissue regeneration. The aim of this study was to evaluate the effect of red and near infrared (NIR) photobiomodulation (PBM) on macrophage phenotypes and correlate these findings with the repair process following acute muscle injury. Wistar rats were divided into 4 groups: control; muscle injury; muscle injury + red PBM; and muscle injury + NIR PBM. After 2, 4 and 7 days, the tibialis anterior muscle was processed for analysis. Macrophages phenotypic profile was evaluated by immunohistochemistry and correlated with the different stages of the skeletal muscle repair by the qualitative and quantitative morphological analysis as well as by the evaluation of IL‐6,TNF‐α and TGF‐β mRNA expression. Photobiomodulation at both wavelengths was able to decrease the number of CD68+ (M1) macrophages 2 days after muscle injury and increase the number of CD163+ (M2) macrophages 7 days after injury. However, only NIR treatment was able to increase the number of CD206+ M2 macrophages (Day 2) and TGF ‐β mRNA expression (Day 2, 4 and 7), favouring the repair process more expressivelly. Treatment with PBM was able to modulate the inflammation phase, optimize the transition from the inflammatory to the regeneration phase (mainly with NIR light) and improve the final step of regeneration, enhancing tissue repair.

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“…[30][31][32] Moreover, in vivo and in vitro studies have shown that exposure to light causes changes in inflammatory cell migration into the injured spinal cord [33][34][35][36] and modulates microglia polarization from a proinflammatory to anti-inflammatory phenotype. 37 After peripheral (sciatic) nerve injury, the transcutaneous application of laser light over the corresponding segment of the spinal cord improved measures of nerve function and neurologic recovery in rats, compared with values for (non-laser-light-treated) controls. 38,39 To the author's knowledge, only 2 clinical trials on photobiomodulation therapy in dogs with naturally occurring SCI have been conducted.…”

Section: Ivddmentioning

confidence: 98%

Preliminary evaluation of the effects of photobiomodulation therapy and physical rehabilitation on early postoperative recovery of dogs undergoing hemilaminectomy for treatment of thoracolumbar intervertebral disk disease

Bennaim¹,

Porato

Jarleton³

et al. 2017

ajvr

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OBJECTIVE To evaluate the effects of postoperative photobiomodulation therapy and physical rehabilitation on early recovery variables for dogs after hemilaminectomy for treatment of intervertebral disk disease. ANIMALS 32 nonambulatory client-owned dogs. PROCEDURES Dogs received standard postoperative care with photobiomodulation therapy (n = 11), physical rehabilitation with sham photobiomodulation treatment (11), or sham photobiomodulation treatment only (10) after surgery. Neurologic status at admission, diagnostic and surgical variables, duration of postoperative IV analgesic administration, and recovery grades (over 10 days after surgery) were assessed. Time to reach recovery grades B (able to support weight with some help), C (initial limb movements present), and D (ambulatory [≥ 3 steps unassisted]) was compared among groups. Factors associated with ability to ambulate on day 10 or at last follow-up were assessed. RESULTS Time to reach recovery grades B, C, and D and duration of postoperative IV opioid administration did not differ among groups. Neurologic score at admission and surgeon experience were negatively associated with the dogs' ability to ambulate on day 10. The number of disk herniations identified by diagnostic imaging before surgery was negatively associated with ambulatory status at last follow-up. No other significant associations and no adverse treatment-related events were identified. CONCLUSIONS AND CLINICAL RELEVANCE This study found no difference in recovery-related variables among dogs that received photobiomodulation therapy, physical rehabilitation with sham photobiomodulation treatment, or sham photobiomodulation treatment only. Larger studies are needed to better evaluate effects of these postoperative treatments on dogs treated surgically for intervertebral disk disease.

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808 nm Wavelength Light Induces a Dose‐Dependent Alteration in Microglial Polarization and Resultant Microglial Induced Neurite Growth

Cited by 48 publications

References 35 publications

Red LED photobiomodulation reduces pain hypersensitivity and improves sensorimotor function following mild T10 hemicontusion spinal cord injury

Red LED photobiomodulation reduces pain hypersensitivity and improves sensorimotor function following mild T10 hemicontusion spinal cord injury

Photobiomodulation and different macrophages phenotypes during muscle tissue repair

Preliminary evaluation of the effects of photobiomodulation therapy and physical rehabilitation on early postoperative recovery of dogs undergoing hemilaminectomy for treatment of thoracolumbar intervertebral disk disease

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