Comparison of therapeutic effects between pulsed and continuous wave 810-nm wavelength laser irradiation for traumatic brain injury in mice

Background and Objective

Transcranial low-level laser therapy (LLLT) using near-infrared light can efficiently penetrate through the scalp and skull and could allow non-invasive treatment for traumatic brain injury (TBI). In the present study, we compared the therapeutic effect using 810-nm wavelength laser light in continuous and pulsed wave modes in a mouse model of TBI.

Study Design/Materials and Methods

TBI was induced by a controlled cortical-impact device and 4-hours post-TBI 1-group received a sham treatment and 3-groups received a single exposure to transcranial LLLT, either continuous wave or pulsed at 10-Hz or 100-Hz with a 50% duty cycle. An 810-nm Ga-Al-As diode laser delivered a spot with diameter of 1-cm onto the injured head with a power density of 50-mW/cm² for 12-minutes giving a fluence of 36-J/cm². Neurological severity score (NSS) and body weight were measured up to 4 weeks. Mice were sacrificed at 2, 15 and 28 days post-TBI and the lesion size was histologically analyzed. The quantity of ATP production in the brain tissue was determined immediately after laser irradiation. We examined the role of LLLT on the psychological state of the mice at 1 day and 4 weeks after TBI using tail suspension test and forced swim test.

Results

The 810-nm laser pulsed at 10-Hz was the most effective judged by improvement in NSS and body weight although the other laser regimens were also effective. The brain lesion volume of mice treated with 10-Hz pulsed-laser irradiation was significantly lower than control group at 15-days and 4-weeks post-TBI. Moreover, we found an antidepressant effect of LLLT at 4-weeks as shown by forced swim and tail suspension tests.

Conclusion

The therapeutic effect of LLLT for TBI with an 810-nm laser was more effective at 10-Hz pulse frequency than at CW and 100-Hz. This finding may provide a new insight into biological mechanisms of LLLT.     

Low‐level laser therapy for traumatic brain injury in mice increases brain derived neurotrophic factor (BDNF) and synaptogenesis

Transcranial low‐level laser (light) therapy (LLLT) is a new non‐invasive approach to treating a range of brain disorders including traumatic brain injury (TBI). We (and others) have shown that applying near‐infrared light to the head of animals that have suffered TBI produces improvement in neurological functioning, lessens the size of the brain lesion, reduces neuroinflammation, and stimulates the formation of new neurons. In the present study we used a controlled cortical impact TBI in mice and treated the mice either once (4 h post‐TBI, 1‐laser), or three daily applications (3‐laser) with 810 nm CW laser 36 J/cm² at 50 mW/cm². Similar to previous studies, the neurological severity score improved in laser‐treated mice compared to untreated TBI mice at day 14 and continued to further improve at days 21 and 28 with 3‐laser being better than 1‐laser. Mice were sacrificed at days 7 and 28 and brains removed for immunofluorescence analysis. Brain‐derived neurotrophic factor (BDNF) was significantly upregulated by laser treatment in the dentate gyrus of the hippocampus (DG) and the subventricular zone (SVZ) but not in the perilesional cortex (lesion) at day 7 but not at day 28. Synapsin‐1 (a marker for synaptogenesis, the formation of new connections between existing neurons) was significantly upregulated in lesion and SVZ but not DG, at 28 days but not 7 days. The data suggest that the benefit of LLLT to the brain is partly mediated by stimulation of BDNF production, which may in turn encourage synaptogenesis. Moreover the pleiotropic benefits of BDNF in the brain suggest LLLT may have wider applications to neurodegenerative and psychiatric disorders.

Neurological Severity Score (NSS) for TBI mice     

Low-Level Laser Irradiation Improves Functional Recovery and Nerve Regeneration in Sciatic Nerve Crush Rat Injury Model

The development of noninvasive approaches to facilitate the regeneration of post-traumatic nerve injury is important for clinical rehabilitation. In this study, we investigated the effective dose of noninvasive 808-nm low-level laser therapy (LLLT) on sciatic nerve crush rat injury model. Thirty-six male Sprague Dawley rats were divided into 6 experimental groups: a normal group with or without 808-nm LLLT at 8 J/cm² and a sciatic nerve crush injury group with or without 808-nm LLLT at 3, 8 or 15 J/cm². Rats were given consecutive transcutaneous LLLT at the crush site and sacrificed 20 days after the crush injury. Functional assessments of nerve regeneration were analyzed using the sciatic functional index (SFI) and hindlimb range of motion (ROM). Nerve regeneration was investigated by measuring the myelin sheath thickness of the sciatic nerve using transmission electron microscopy (TEM) and by analyzing the expression of growth-associated protein 43 (GAP43) in sciatic nerve using western blot and immunofluorescence staining. We found that sciatic-injured rats that were irradiated with LLLT at both 3 and 8 J/cm² had significantly improved SFI but that a significant improvement of ROM was only found in rats with LLLT at 8 J/cm². Furthermore, the myelin sheath thickness and GAP43 expression levels were significantly enhanced in sciatic nerve-crushed rats receiving 808-nm LLLT at 3 and 8 J/cm². Taken together, these results suggest that 808-nm LLLT at a low energy density (3 J/cm² and 8 J/cm²) is capable of enhancing sciatic nerve regeneration following a crush injury.     

Low-level laser therapy attenuates the acute inflammatory response induced by muscle traumatic injury

The purpose of this work was to investigate the effect of early and long-term low-level laser therapy (LLLT) on oxidative stress and inflammatory biomarkers after acute-traumatic muscle injury in Wistar rats. Animals were randomly divided into the following four groups: control group (CG), muscle injury group (IG), CG?+?LLLT, and IG?+?LLLT: laser treatment with doses of 3 and 5 J/cm². Muscle traumatic injury was induced by a single-impact blunt trauma in the rat gastrocnemius. Irradiation for 3 or 5 J/cm² was initiated 2, 12, and 24?h after muscle trauma induction, and the treatment was continued for five consecutive days. All the oxidant markers investigated. namely thiobarbituric acid-reactive substance, carbonyl, superoxide dismutase, glutathione peroxidase, and catalase, were increased as soon as 2?h after muscle injury and remained increased up to 24?h. These alterations were prevented by LLLT at a 3 J/cm² dose given 2?h after the trauma. Similarly, LLLT prevented the trauma-induced proinflammatory state characterized by IL-6 and IL-10. In parallel, trauma-induced reduction in BDNF and VEGF, vascular remodeling and fiber-proliferating markers, was prevented by laser irradiation. In order to test whether the preventive effect of LLLT was also reflected in muscle functionality, we tested the locomotor activity, by measuring distance traveled and the number of rearings in the open field test. LLLT was effective in recovering the normal locomotion, indicating that the irradiation induced biostimulatory effects that accelerated or resolved the acute inflammatory response as well as the oxidant state elicited by the muscle trauma.     

810nm弱激光照射对大鼠急性脊髓损伤后巨噬细胞极化的作用研究

本研究构建急性大鼠脊髓夹伤模型,并将大鼠随机分为单纯脊髓损伤对照组及脊髓损伤联合弱激光照射组。照射组应用810 nm波长,150 m W照射功率,照射光斑0.3 cm^2的弱激光对脊髓损伤区进行经皮照射,连续照射3天,7天或14天。应用免疫荧光、免疫印迹实验方法,测定脊髓损伤区巨噬细胞及小胶质细胞的极化表达。应用酶联免疫吸附法测定脊髓损伤区白细胞介素4的表达情况。应用坚牢蓝髓鞘染色测定两组损伤脊髓中髓鞘保留的差异。采用BBB评分对两组大鼠后肢运动功能的恢复进行评估。结果表明,810 nm弱激光对脊髓损伤区连续照射3天,7天后,可显著减少M1型巨噬细胞及其标志物诱导型一氧化氮合酶的表达,在7天时间增加M2型巨噬细胞及其标志物精氨酸酶1的表达。弱激光照射组白细胞介素4的表达明显增加。损伤后14天,弱激光照射组脊髓损伤区髓鞘保留面积比值明显提高。损伤后7天及14天时,弱激光照射组大鼠的BBB评分明显升高。该实验结果表明,810 nm弱激光经皮照射,可增加大鼠急性脊髓损伤区M2型巨噬细胞及小胶质细胞的表达,并减少脊髓损伤后的髓鞘脱失,促进脊髓损伤大鼠运动功能的恢复。     

Biochemical changes induced by grape seed extract and low level laser therapy administration during intraoral wound healing in rat liver: an experimental and in silico study

In the present study, the changes that occur in rat liver tissue as a result of the use of grape seed extract (GSE) and low level laser therapy (LLLT) in intraoral wound (IW) healing are analyzed using biochemical parameters. Diode laser application groups received 8 J/cm² dose LLLT once a day for 4 days (810 nm wavelength, continuous mode, 0.25 W, 9 s). As a result of the biological parameter analysis, it was determined that the oxidative damage caused by the IWs and recovery period on 7th and 14th days could be substantially removed with GSE applications that have antioxidant capacity especially in rat liver tissue. In addition, the active compound of grape seed, catechin is studied in the active site of glycogen synthase kinase 3 (GSK3) target using molecular modeling approaches. Post-processing molecular dynamics (MD) results for catechin is compared with a standard GSK3 inhibitor. MD simulations assisted for better understanding of inhibition mechanism and the crucial amino acids contributing in the ligand binding. These results along with a through free energy analysis of ligands using sophisticated simulations methods are quite striking and it suggests a greater future role for simulation in deciphering complex patterns of molecular mechanism in combination with methods for understanding drug-receptor interactions.     

Low-level laser therapy activates NF-kB via generation of reactive oxygen species in mouse embryonic fibroblasts

Background

Despite over forty years of investigation on low-level light therapy (LLLT), the fundamental mechanisms underlying photobiomodulation at a cellular level remain unclear.

Methodology/Principal Findings

In this study, we isolated murine embryonic fibroblasts (MEF) from transgenic NF-kB luciferase reporter mice and studied their response to 810 nm laser radiation. Significant activation of NF-kB was observed at fluences higher than 0.003 J/cm² and was confirmed by Western blot analysis. NF-kB was activated earlier (1 hour) by LLLT compared to conventional lipopolysaccharide treatment. We also observed that LLLT induced intracellular reactive oxygen species (ROS) production similar to mitochondrial inhibitors, such as antimycin A, rotenone and paraquat. Furthermore, we observed similar NF-kB activation with these mitochondrial inhibitors. These results, together with inhibition of laser induced NF-kB activation by antioxidants, suggests that ROS play an important role in the laser induced NF-kB signaling pathways. However, LLLT, unlike mitochondrial inhibitors, induced increased cellular ATP levels, which indicates that LLLT also upregulates mitochondrial respiration.

Conclusion

We conclude that LLLT not only enhances mitochondrial respiration, but also activates the redox-sensitive NFkB signaling via generation of ROS. Expression of anti-apoptosis and pro-survival genes responsive to NFkB could explain many clinical effects of LLLT.     

Low‐level laser therapy (810 nm) protects primary cortical neurons against excitotoxicity in vitro

Excitotoxicity describes a pathogenic process whereby death of neurons releases large amounts of the excitatory neurotransmitter glutamate, which then proceeds to activate a set of glutamatergic receptors on neighboring neurons (glutamate, N‐methyl‐D‐aspartate (NMDA), and kainate), opening ion channels leading to an influx of calcium ions producing mitochondrial dysfunction and cell death. Excitotoxicity contributes to brain damage after stroke, traumatic brain injury, and neurodegenerative diseases, and is also involved in spinal cord injury. We tested whether low level laser (light) therapy (LLLT) at 810 nm could protect primary murine cultured cortical neurons against excitotoxicity in vitro produced by addition of glutamate, NMDA or kainate. Although the prevention of cell death was modest but significant, LLLT (3 J/cm² delivered at 25 mW/cm² over 2 min) gave highly significant benefits in increasing ATP, raising mitochondrial membrane potential, reducing intracellular calcium concentrations, reducing oxidative stress and reducing nitric oxide. The action of LLLT in abrogating excitotoxicity may play a role in explaining its beneficial effects in diverse central nervous system pathologies. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

B-cell amplification by dibutyryl cyclic AMP in mice

Mice injected with N⁶-2′-O-dibutyryl-adenosine 3′,5′ monophosphate (DBcAMP) showed increased anti-sheep erythrocyte (anti-SE) antibody plaque-forming spleen cell (PFC) responses up to 7-fold greater than control mice. The amount of increase was related to the immunizing dose of SE and to the dose of DBcAMP, and it was more pronounced in 19S PFC than in 7S PFC. Mice thymectomized (Tx) within 16 hr after birth and injected with SE and DBcAMP at 40 days showed a 2.7-fold greater anti-SE PFC response than Tx controls injected with SE alone. DBcAMP restored the PFC response of Tx mice to 75% of that seen for sham Tx, DBcAMP-treated controls. These data suggest that a T cell-B cell interaction is not stringently required in mouse anti-SE antibody responses in vivo, since a T cell-like effect may be substituted or a minimal response can be enhanced with a soluble amplifier such as dibutyryl cyclic AMP.     

Which wavelength is optimal for transcranial low‐level laser stimulation?

One of the challenges in transcranial low‐level laser therapy (LLLT) is to optimally choose illumination parameters, such as wavelength. However, there is sparse study on the wavelengths comparison especially on human transcranial LLLT. Here, we employed Monte Carlo modeling and visible human phantom to compute the penetrated photon fluence distribution within cerebral cortex. By comparing the fluence distribution, penetration depth and the intensity of laser‐tissue‐interaction within brain among all candidate wavelengths, we found that 660, 810 nm performed much better than 980, 1064 nm with much stronger, deeper and wider photon penetration into cerebral tissue; 660 nm was shown to be the best and slightly better than 810 nm. Our computational finding was in a surprising accordance with previous LLLT‐neurobehavioral studies on mice. This study not only offered quantitative comparison among wavelengths in the effect of LLLT light penetration effectiveness but also anticipated a delightful possibility of online, precise and visible optimization of LLLT illumination parameters.      

Modulation of immune response to induced‐arthritis by low‐level laser therapy

As low‐level laser therapy immune cells responses are not always clarified, this study aimed to evaluate cytokines and immune cells profile after low‐level laser therapy (LLLT) on arthritis‐induced model. Arthritis was induced in C57BL/6 mice divided into five groups: euthanized 5 hours after inflammation induction; untreated; dexamethasone treated; LLLT at 3 Jcm^?2; LLLT at 30 Jcm^?2. Cytokine measurements by enzyme‐linked immunosorbent assay and mRNA cytokine relative levels by real‐time quantitative polymerase chain reaction were performed with arthritic ankle (IL‐1β, IL‐6, TNF‐α, IL‐10 and TGF‐β). Macrophages, dendritic cells, natural killer cells, lymphocytes CD4⁺, CD8⁺, Treg and costimulatory proteins were quantified in proximal lymph node by flow cytometry. Data showed decrease in all cytokine levels after LLLT and alteration in mRNA relative levels, depending on the energy density used. LLLT was able to increase of immune cell populations analyzed in the lymph node as well as costimulatory proteins expression on macrophages and dendritic cells. Treg TCD4⁺ and TCD8⁺ population enrichment were observed in LLLT at 3 and 30 Jcm^?2 groups, respectively. Furthermore, Treg TCD8⁺ cells expressing higher levels of CD25 were observed at LLLT at 30 Jcm^?2 group. Our results indicate that LLLT could change the inflammatory course of arthritis, tending to accelerate its resolution through immune cells photobiostimulation.      

Superpulsed (Ga‐As, 904 nm) low‐level laser therapy (LLLT) attenuates inflammatory response and enhances healing of burn wounds

Low‐level laser therapy (LLLT) using superpulsed near‐infrared light can penetrate deeper in the injured tissue and could allow non‐pharmacological treatment for chronic wound healing. This study investigated the effects of superpulsed laser (Ga‐As 904 nm, 200 ns pulse width; 100 Hz; 0.7 mW mean output power; 0.4 mW/cm² average irradiance; 0.2 J/cm² total fluence) on the healing of burn wounds in rats, and further explored the probable associated mechanisms of action. Irradiated group exhibited enhanced DNA, total protein, hydroxyproline and hexosamine contents compared to the control and silver sulfadiazine (reference care) treated groups. LLLT exhibited decreased TNF‐α level and NF‐kB, and up‐regulated protein levels of VEGF, FGFR‐1, HSP‐60, HSP‐90, HIF‐1α and matrix metalloproteinases‐2 and 9 compared to the controls. In conclusion, LLLT using superpulsed 904 nm laser reduced the inflammatory response and was able to enhance cellular proliferation, collagen deposition and wound contraction in the repair process of burn wounds.

Photomicrographs showing no, absence inflammation and faster wound contraction in LLLT superpulsed (904 nm) laser treated burn wounds as compared to the non‐irradiated control and silver sulfadiazine (SSD) ointment (reference care) treated wounds     

Oligodendrocyte Birth and Death following Traumatic Brain Injury in Adult Mice

Oligodendrocytes are responsible for producing and maintaining myelin throughout the CNS. One of the pathological features observed following traumatic brain injury (TBI) is the progressive demyelination and degeneration of axons within white matter tracts. While the effect of TBI on axonal health has been well documented, there is limited information regarding the response of oligodendrocytes within these areas. The aim of this study was to characterize the response of both mature oligodendrocytes and immature proliferative oligodendrocyte lineage cells across a 3 month timecourse following TBI. A computer-controlled cortical impact model was used to produce a focal lesion in the left motor cortex of adult mice. Immunohistochemical analyses were performed at 48 hours, 7 days, 2 weeks, 5 weeks and 3 months following injury to assess the prevalence of mature CC-1⁺ oligodendrocyte cell death, immature Olig2⁺ cell proliferation and longer term survival in the corpus callosum and external capsule. Decreased CC-1 immunoreactivity was observed in white matter adjacent to the site of injury from 2 days to 2 weeks post TBI, with ongoing mature oligodendrocyte apoptosis after this time. Conversely, proliferation of Olig2⁺ cells was observed as early as 48 hours post TBI and significant numbers of these cells and their progeny survived and remained in the external capsule within the injured hemisphere until at least 3 months post injury. These findings demonstrate that immature oligodendrocyte lineage cells respond to TBI by replacing oligodendrocytes lost due to damage and that this process occurs for months after injury.     

Low‐level laser irradiation promotes the proliferation and maturation of keratinocytes during epithelial wound repair

Low‐level laser therapy (LLLT) has been extensively employed to improve epithelial wound healing, though the exact response of epithelium maturation and stratification after LLLT is unknown. Thus, this study aimed to assess the in vitro growth and differentiation of keratinocytes (KCs) and in vivo wound healing response when treated with LLLT. Human KCs (HaCaT cells) showed an enhanced proliferation with all the employed laser energy densities (3, 6 and 12 J/cm², 660 nm, 100 mW), together with an increased expression of Cyclin D1. Moreover, the immunoexpression of proteins related to epithelial proliferation and maturation (p63, CK10, CK14) all indicated a faster maturation of the migrating KCs in the LLLT‐treated wounds. In that way, an improved epithelial healing was promoted by LLLT with the employed parameters; this improvement was confirmed by changes in the expression of several proteins related to epithelial proliferation and maturation.

Immunofluorescent expression of cytokeratin 10 (red) and Cyclin D1 (green) in ( A ) Control keratinocytes and ( B ) Low‐level laser irradiated cells. Blue color illustrates the nuclei of the cells (DAPI staining).     

Effect of low‐level laser therapy and oxytocin on osteoporotic bone marrow‐derived mesenchymal stem cells

Postmenopausal osteoporosis (OP) is a major concern for public health. Low‐level laser therapy (LLLT) has a positive effect on the health of bone marrow mesenchymal stem cells (BMMSCs). The purpose of this study is to evaluate the influence of LLLT and oxytocin (OT) incubation—individually and in combination—on osteoporotic BMMSCs in ovariectomized rats. Twelve female rats were randomized into two groups to undergo either a sham surgery (sham group) or ovariectomy‐induced osteoporosis (OVX group). MSCs harvested from the BM of healthy and OVX rats underwent culture expansion. There were five groups. In Groups one (sham‐BMMSC) and two (OVX‐BMMSC) the cells were held in osteogenic condition medium without any intervention. In the group three (OT), OT incubation with optimum dose was performed for 48 h (two times, 10^?12 molar). In Group four, laser‐treated‐OVX‐BMMSCs were treated with optimum protocol of LLLT (one time, 1.2 J/cm²). In Group five (laser + OT group), the OT incubation plus the laser irradiation was performed. The biostimulatory effect of LLLT is demonstrated by a significant increase in the viability of OVX‐BMMSCs, cell cycle, and extracellular levels of Transforming growth factor beta (TGF‐β), insulin‐like growth factor‐I (IGF‐I), and Alkaline phosphatase (ALP) compared to control OVX‐BMMSCs and/or the sham group. OT incubation and laser + OT incubation have a positive effect on OVX‐BMMSCs. However, LLLT is more effective statistically. We conclude that LLLT significantly improved cell viability, enhanced the osteogenic potential of the OVX‐BMMSCs, and increased the extracellular levels of the TGF‐β, IGF‐I, and ALP.     

Oxidative stress in head trauma in aging

Oxidative damage is proposed as a key mediator of exacerbated morphological responses and deficits in behavioral recovery in aged subjects with traumatic brain injury (TBI). In the present study, we show exacerbated loss of tissue in middle aged (12 months) and aged (22 months) Fisher-344 rats compared to young animals (3 months) subjected to moderate TBI. Analysis of 4-hydroxynonenal (4-HNE) and acrolein, neurotoxic by-products of lipid peroxidation, shows significant (P < 0.05) age-dependent increases in ipsilateral (IP) hippocampus 1 and 7 days post injury. In IP cortex, 4-HNE was significantly elevated 1 day post injury in all age groups, and both 4-HNE and acrolein were elevated in middle aged and aged animals 7 days post injury. Comparison of antioxidant enzyme activities shows significant (P < 0.05) age-dependent decreases of manganese superoxide dismutase in IP hippocampus and cortex 1 and 7 days post injury. Glutathione reductase activity also showed an age-dependent decrease. Overall, our data show increased levels of oxidative damage, diminished antioxidant capacities, and increased tissue loss in TBI in aging.     

Effect of low-level laser therapy on the expression of inflammatory mediators and on neutrophils and macrophages in acute joint inflammation

Introduction

Inflammation of the synovial membrane plays an important role in the pathophysiology of osteoarthritis (OA). The synovial tissue of patients with initial OA is characterized by infiltration of mononuclear cells and production of proinflammatory cytokines and other mediators of joint injury. The objective was to evaluate the effect of low-level laser therapy (LLLT) operating at 50 mW and 100 mW on joint inflammation in rats induced by papain, through histopathological analysis, differential counts of inflammatory cells (macrophages and neutrophils), as well as gene expression of interleukin 1-beta and 6 (IL-1β and IL-6), and protein expression of tumor necrosis factor alpha (TNFα).

Methods

Male Wistar rats (n = 60) were randomly divided into four groups of 15 animals, namely: a negative control group; an inflammation injury positive control group; a 50 mW LLLT group, subjected to injury and treated with 50 mW LLLT; and a 100 mW LLLT group, subjected to injury and treated with 100 mW LLLT. The animals were subject to joint inflammation (papain solution, 4%) and then treated with LLLT (808 nm, 4 J, 142.4 J/cm², spot size 0.028 for both groups). On the day of euthanasia, articular lavage was collected and immediately centrifuged; the supernatant was saved for analysis of expression of TNFα protein by enzyme-linked immunosorbent assay and expression of IL-1β and IL-6 mRNA by real-time polymerase chain reaction. A histologic examination of joint tissue was also performed. For the statistical analysis, analysis of variance with Tukey''s post-hoc test was used for comparisons between each group. All data are expressed as mean values and standard deviation, with P < 0.05.

Results

Laser treatment with 50 mW was more efficient than 100 mW in reducing cellular inflammation, and decreased the expression of IL-1β and IL-6. However, the 100 mW treatment led to a higher reduction of TNFα compared with the 50 mW treatment.

Conclusions

LLLT with 50 mW was more efficient in modulating inflammatory mediators (IL-1β, IL-6) and inflammatory cells (macrophages and neutrophils), which correlated with the histology that showed a reduction in the inflammatory process.     

Low-level laser therapy with 850 nm recovers salivary function via membrane redistribution of aquaporin 5 by reducing intracellular Ca2+ overload and ER stress during hyperglycemia

The overall goal is to study the effect of low-level laser therapy (LLLT) on membrane distribution of major water channel protein aquaporin 5 (AQP5) in salivary gland during hyperglycemia. Par C10 cells treated with high glucose (50?mM) showed a reduced membrane distribution of AQP5. The functional expression of AQP5 was downregulated due to intracellular Ca²⁺ overload and ER stress. This reduction in AQP5 expression impairs water permeability and therefore results in hypo-salivation. A reduced salivary flow was also observed in streptozotocin (STZ)-induced diabetic mice model and the expression of AQP5 and phospho-AQP5 was downregulated. Low-level laser treatment with 850?nm (30?mW, 10?min?=?18?J/cm²) reduced ER stress and recovered AQP5 membrane distribution via serine phosphorylation in the cells. In the STZ-induced diabetic mouse, LLLT with 850?nm (60?J/cm²) increased salivary flow and upregulated of AQP5 and p-AQP5. ER stress was also reduced via downregulation of caspase 12 and CHOP. In silico analysis confirmed that the serine 156 is one of the most favorable phosphorylation sites of AQP5 and may contribute to the stability of the protein. Therefore, this study suggests high glucose inhibits phosphorylation-dependent AQP5 membrane distribution. High glucose induces intracellular Ca²⁺ overload and ER stress that disrupt AQP5 functional expression. Low-level laser therapy with 850?nm improves salivary function by increasing AQP5 membrane distribution in hyperglycemia-induced hyposalivation.     

Red and Infrared Low-Level Laser Therapy Prior to Injury with or without Administration after Injury Modulate Oxidative Stress during the Muscle Repair Process

IntroductionMuscle injury is common among athletes and amateur practitioners of sports. Following an injury, the production of reactive oxygen species (ROS) occurs, which can harm healthy muscle fibers (secondary damage) and delay the repair process. Low-level laser therapy (LLLT) administered prior to or following an injury has demonstrated positive and protective effects on muscle repair, but the combination of both administration times together has not been clarified.AimTo evaluate the effect of LLLT (660 nm and 780 nm, 10 J/cm², 40 mW, 3.2 J) prior to injury with or without the administration after injury on oxidative stress during the muscle repair process.MethodsWistar rats were divided into following groups: control; muscle injury alone; LLLT 660 nm + injury; LLLT 780 nm + injury; LLLT 660 nm before and after injury; and LLLT 780 nm before and after injury. The rats were euthanized on days 1, 3 and 7 following cryoinjury of the tibialis anterior (TA) muscle, which was then removed for analysis.ResultsLipid peroxidation decreased in the 660+injury group after one day. Moreover, red and infrared LLLT employed at both administration times induced a decrease in lipid peroxidation after seven days. CAT activity was altered by LLLT in all periods evaluated, with a decrease after one day in the 780+injury+780 group and after seven days in the 780+injury group as well as an increase in the 780+injury and 780+injury+780 groups after three days. Furthermore, increases in GPx and SOD activity were found after seven days in the 780+injury+780 group.ConclusionThe administration of red and infrared laser therapy at different times positively modulates the activity of antioxidant enzymes and reduces stress markers during the muscle repair process.     

Acute dosing of latrepirdine (Dimebon™), a possible Alzheimer therapeutic, elevates extracellular amyloid-β levels in vitro and in vivo

Background

It has been hypothesized that reduced axonal transport contributes to the degeneration of neuronal processes in Parkinson's disease (PD). Mitochondria supply the adenosine triphosphate (ATP) needed to support axonal transport and contribute to many other cellular functions essential for the survival of neuronal cells. Furthermore, mitochondria in PD tissues are metabolically and functionally compromised. To address this hypothesis, we measured the velocity of mitochondrial movement in human transmitochondrial cybrid "cytoplasmic hybrid" neuronal cells bearing mitochondrial DNA from patients with sporadic PD and disease-free age-matched volunteer controls (CNT). The absorption of low level, near-infrared laser light by components of the mitochondrial electron transport chain (mtETC) enhances mitochondrial metabolism, stimulates oxidative phosphorylation and improves redox capacity. PD and CNT cybrid neuronal cells were exposed to near-infrared laser light to determine if the velocity of mitochondrial movement can be restored by low level light therapy (LLLT). Axonal transport of labeled mitochondria was documented by time lapse microscopy in dopaminergic PD and CNT cybrid neuronal cells before and after illumination with an 810 nm diode laser (50 mW/cm²) for 40 seconds. Oxygen utilization and assembly of mtETC complexes were also determined.

Results

The velocity of mitochondrial movement in PD cybrid neuronal cells (0.175 +/- 0.005 SEM) was significantly reduced (p < 0.02) compared to mitochondrial movement in disease free CNT cybrid neuronal cells (0.232 +/- 0.017 SEM). For two hours after LLLT, the average velocity of mitochondrial movement in PD cybrid neurites was significantly (p < 0.003) increased (to 0.224 +/- 0.02 SEM) and restored to levels comparable to CNT. Mitochondrial movement in CNT cybrid neurites was unaltered by LLLT (0.232 +/- 0.017 SEM). Assembly of complexes in the mtETC was reduced and oxygen utilization was altered in PD cybrid neuronal cells. PD cybrid neuronal cell lines with the most dysfunctional mtETC assembly and oxygen utilization profiles were least responsive to LLLT.

Conclusion

The results from this study support our proposal that axonal transport is reduced in sporadic PD and that a single, brief treatment with near-infrared light can restore axonal transport to control levels. These results are the first demonstration that LLLT can increase axonal transport in model human dopaminergic neuronal cells and they suggest that LLLT could be developed as a novel treatment to improve neuronal function in patients with PD.