Effects of Photobiomodulation with Low-level Laser Therapy on Muscle Repair Following a Peripheral Nerve Injury in Wistar Rats.

Peripheral nerve injury (PNI) can lead to sensory and/or motor impairment. As a treatment photobiomodulation (PBM) has demonstrated positive effects in terms of the maintenance of muscle activation and trophism. Wistar rats were divided into five groups: control, injury, injury + PBMn (irradiation over injured nerve), injury + PBMm (irradiation over affected muscle) and injury + PBMnm (irradiation over nerve and muscle). The left sciatic nerve was submitted to a crushing injury. Treatment was administered with low-level laser (780 nm, 0.04 cm2 , 1 W cm-2 , 3.2 J) over the injured nerve and/or the tibialis anterior muscle. The effects of PBM were favorable on muscle morphology and gene expression of calcineurin, myogenin and acetylcholine receptors. PBM led to an acceleration on muscle repair process, and effects were more evident in 2 weeks after PNI. Thus, PBM is indicated for the area over both the injured nerve and the affected muscle.

Photobiomodulation and different macrophages phenotypes during muscle tissue repair.

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-ß 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-ß 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.

Photobiomodulation versus light-emitting diode (LED) therapy in the treatment of temporomandibular disorder: study protocol for a randomized, controlled clinical trial.

BACKGROUND: Temporomandibular disorder (TMD) is described as a subgroup of orofacial pain with a set of signs and symptoms that involve the temporomandibular joint, masticatory muscles, ears, and neck. TMD can occur unilaterally or bilaterally and approximately 70% of the population is affected with at least one sign. The disorder progresses with orofacial pain, muscle pain involving the masticatory and cervical muscles, joint noises (clicks and pops), joint block, mandibular dysfunction, and headache. The etiology can be abnormal occlusion and/or posture, trauma involving local tissues, repetitive microtrauma, parafunctional habits, and an increase in emotional stress. Studies have demonstrated that phototherapy is an efficient option for the treatment of TMD, leading to improvements in pain and orofacial function. METHODS: The aim of the proposed study is to compare the effects of two sources of photobiomodulation in individuals with TMD. A randomized, controlled, double-blind, clinical trial is proposed, which will involve 80 individuals aged 18-65 years allocated to either a laser group or light-emitting diode (LED) group submitted to 12 sessions of phototherapy. The Research Diagnostic Criteria for TMDs will be used to evaluate all participants. Pain will be measured using the visual analog scale and maximum vertical mandibular movement will be determined with the aid of digital calipers. DISCUSSION: This study compares the effects of two modalities of laser therapy on the pain and orofacial function of patients with TMD dysfunction. Photobiomodulation and LED therapy are treatment options for reducing the inflammatory process and pain as well as inducing the regeneration of the target tissue. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03257748 . Registered on 8 August 2017.

No effect of low-level lasers on in vitro myoblast culture.

Effects of phototherapy using low-level lasers depend on irradiation parameters and the type of laser used. The aim of the present study was to evaluate the effect of phototherapy on the proliferation of cultured C2C12 myoblasts under different nutritional conditions using low-level GaAlAs and InGaAlP lasers with different parameters and incubation periods. C2C12 cells cultured in regular and nutrient-deficient medium were irradiated with low-level GaAlAs (780 nm) and InGaA1P (660 nm) lasers with energy densities of 3.8, 6.3 and 10 J/cm2, and 3.8, 10 and 17.5 J/cm2, respectively. Cell proliferation was assessed 48 and 72 h after irradiation by MTT assay. There were no significant differences in cell proliferation between laser-treated myoblasts and control cultures for any of the parameters and incubation periods. Further studies are necessary to determine the correct laser parameters for optimizing the biostirhulation of myoblasts.

Healing action of topical chamomile on 5-fluoracil induced oral mucositis in hamster.

BACKGROUND: Oral mucositis is a common complication in the treatment of cancer. Its management and prevention are seen as high priority in cancer patient care. The aim of the present study was to investigate the effect of topical chamomile in the treatment of oral mucositis induced by 5-fluoracil (5-FU) in hamsters. MATERIALS AND METHODS: One hundred five hamsters were randomly separated into three groups (35 animals each): group I--without treatment (control); group II--treatment with chamomile (Ad-Muc®); and group III--treatment with corticoid (betamethasone elixir--Celestone®). The animals received an intraperitoneal injection of 5-FU on days 0 and 2. On days 3 and 4, the buccal mucosa was scratched and therapy was initiated on day 5. Three animals were sacrificed on days 0, 2, 5, 8, 10, 12, 14, and 16, weighed, and the buccal mucosa removed for clinical and histopathological analysis. RESULTS: The animals that developed mucositis and were treated with chamomile or the corticoid agent weighed significantly less than those in the control group. The group treated with the corticoid agent exhibited a more severe clinical condition, whereas the group treated with chamomile exhibited mild mucositis throughout the experiment. The group treated with chamomile had a 12-fold greater chance of scoring zero (absence of mucositis) than the control group. Analysis of the histopathological results demonstrated that the group treated with chamomile exhibited a lesser degree of mucositis throughout the evaluation period in comparison to the control and corticoid groups. CONCLUSION: Chamomile proved effective in the treatment of oral mucositis in a hamster model. However, well-designed clinical studies are needed to confirm the clinical efficacy of this medicine in humans.