Investigating the Relevance of Cyclic Adenosine Monophosphate Response Element-Binding Protein to the Wound Healing Process: An In Vivo Study Using Photobiomodulation Treatment.

Monitoring inflammatory cytokines is crucial for assessing healing process and photobiomodulation (PBM) enhances wound healing. Meanwhile, cAMP response element-binding protein (CREB) is a regulator of cellular metabolism and proliferation. This study explored potential links between inflammatory cytokines and the activity of CREB in PBM-treated wounds. A total of 48 seven-week-old male SD rats were divided into four groups (wound location, skin or oral; treatment method, natural healing or PBM treatment). Wounds with a 6 mm diameter round shape were treated five times with an 808 nm laser every other day (total 60 J). The wound area was measured with a caliper and calculated using the elliptical formula. Histological analysis assessed the epidermal regeneration and collagen expression of skin and oral tissue with H&E and Masson's trichrome staining. Pro-inflammatory (TNF-α) and anti-inflammatory (TGF-ß) cytokines were quantified by RT-PCR. The ratio of phosphorylated CREB (p-CREB) to unphosphorylated CREB was identified through Western blot. PBM treatment significantly reduced the size of the wounds on day 3 and day 7, particularly in the skin wound group (p < 0.05 on day 3, p < 0.001 on day 7). The density of collagen expression was significantly higher in the PBM treatment group (in skin wound, p < 0.05 on day 3, p < 0.001 on day 7, and p < 0.05 on day 14; in oral wound, p < 0.01 on day 7). The TGF-ß/TNF-α ratio and the p-CREB/CREB ratio showed a parallel trend during wound healing. Our findings suggested that the CREB has potential as a meaningful marker to track the wound healing process.

Effectiveness and safety of the ablative fractional 2940-nm Er: YAG laser for the treatment of androgenetic alopecia.

Laser sources have established their potential effect in inducing hair regrowth. No large cohort study has evaluated the effect of ablative fractional 2940-nm erbium yttrium aluminum garnet (Er: YAG) laser in the treatment of androgenetic alopecia (AGA). To investigate the efficacy and safety of the ablative fractional 2940-nm Er: YAG laser in combination with medication therapy for the treatment of AGA. We performed a retrospective study between first July 2021 to 30th December 2021. All included patients received oral finasteride and topical minoxidil, or combined with six sessions of Er: YAG laser at 2-week intervals. Patients were divided into medication or combined therapy groups. The efficacy of the two therapies was evaluated by the investigator's Global Assessment (IGA) scores and the patient's Likert satisfaction scale at week 12 and week 24. Changes in total, terminal and villous hair count, total and terminal hair diameter, and AGA grade were also recorded. Adverse events were evaluated at each follow-up. A total of 192 male patients with AGA were included, including 67 receiving combination treatment, and 125 receiving medication treatment. At week 24, the combination treatment afforded superior outcomes in the IGA score, patient's global assessment, total and terminal hair counts, and diameters (all P<0.05). No severe adverse events were reported in both groups. The combined therapy of ablative fractional Er: YAG laser and medication was superior in treating male AGA than single medication therapy without serious adverse effects.

Combining large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers for promoting protective melanosome autophagy via the PI3K/Akt/mTOR signalling pathway for the treatment of melasma.

Melasma is a common condition of hyperpigmented facial skin. Picosecond lasers are reported to be effective for the treatment of melasma. We aimed to identify the most effective therapeutic mode and elucidate the potential molecular mechanisms of picosecond lasers for the treatment of melasma. Female Kunming mice with melasma-like conditions were treated using four different picosecond laser modes. Concurrently, in vitro experiments were conducted to assess changes in melanin and autophagy in mouse melanoma B16-F10 cells treated with these laser modes. Changes in melanin in mouse skin were detected via Fontana-Masson staining, and melanin particles were evaluated in B16-F10 cells. Real-time polymerase chain reaction and western blotting were used to analyse the expression levels of melanosome and autophagy-related messenger ribonucleic acid (mRNA) and proteins. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers resulted insignificant decreases in melanin as well as in mRNA and protein expression of melanin-synthesizing enzymes (TYR, TRP-1 and MITF). This combination also led to increased expression of the autophagy-related proteins, Beclin1 and ATG5, with a marked decrease in p62 expression. Intervention with the PI3K activator, 740 Y-P, increased TYR, TRP-1, MITF, p-PI3K, p-AKT, p-mTOR and p62 expression but decreased the expression of LC3, ATG5 and Beclin1. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers proved more effective and safer. It inhibits melanin production, downregulates the PI3K/AKT/mTOR pathway, enhances melanocyte autophagy and accelerates melanin metabolism, thereby reducing melanin content.

Photobiomodulation on isolated mitochondria at 810 nm: first results on the efficiency of the energy conversion process.

In this paper the photobiomodulation on isolated mitochondria of bovine liver is studied as a thermodynamic process of conversion of energy. This analysis is conducted by considering a particular set-up for the photobiomodulation experiments of interest. It allows, in particular, the computation of the electromagnetic field and the related energetic quantities in the stimulated organelles. The measurements of the excess of biochemical power density produced by the illuminated mitochondria are performed at regular time intervals after the experiments. The calculations and the measurements finally allow us to obtain the first results on the efficiency of the process of conversion of electromagnetic energy into excess of biochemical energy released by the isolated organelles.

Effectiveness of photobiomodulation and orofacial myofunctional therapy in orofacial pain disorders. A systematic review of randomized control trials.

Orofacial pain can significantly affect physical, psychological, and overall quality of life. This study aimed to compare the effectiveness of combining photobiomodulation (PBM) with orofacial myofunctional therapy (OMT) in managing orofacial pain disorders. An electronic search of randomized controlled trials in electronic databases was performed until March 2024. Randomized controlled trials (RCTs) focusing on PBM and OMT for the management of orofacial pain were included. Risk of bias across individual studies was performed using the Cochrane risk of bias tool for interventions. A total of 10 RCTs were included, out of which 7 RCTs revealed that the combined approach of PBM and OMT had a more pronounced impact on diminishing pain and enhancing functional activity in patients with orofacial disorders. One study reported significant increases in pressure pain threshold for TMJ, masseter, and anterior temporalis muscles at both sides in the post-treatment compared with the pre-treatment in both groups. The risk of bias was low in 7, moderate in 2, and high in 1 study. The efficacy of a combined modality treatment of PBM with OMT for orofacial pain disorder shows promising results. However, further randomized controlled trials with extended follow-up periods standardized PBM and OMT parameters are warranted to obtain firm conclusions.

Low-level laser therapy: an efficient supplement to treatments of vulvar Lichen sclerosus to improve quality of life.

BACKGROUND: Lichen sclerosus (LS) is a chronic, inflammatory disease of the genital and extra genital skin, causing pruritus, soreness, pain and dyspareunia. The aim of this study was to investigate whether Low Level Laser Therapy (LLLT) can improve the quality of life in women with Lichen sclerosus (LS) and insufficient topical treatment. METHODS: In a descriptive prospective observational study conducted between 02.01.2016 and 08.01.2018, we included 100 women with LS with insufficient topical treatment because of poor response of symptoms. All participants received ten LLLT treatments (808 nm and 500 mW) over a period of 8 weeks. The first four treatments were planned as two treatments per week. The remaining six treatments were planned as once a week. A Danish health-related quality of life tool (HRQoL test) monitored the effect. RESULTS: A total of 94 patients completed the study, median age of 62 [InterQuartile Range 53-69]. There was a statistically significant improvement in seven of the eight domains of the HRQoL test after ten LLLT. We found the results of DoloTest to be statistically significant in all of the groups except for smoking (p < 0.094). CONCLUSIONS: LLLT treatment can improve the quality of life in women with LS.

Lichen sclerosus is a chronic, inflammatory disease of the genital and extra genital skin, causing pruritus, soreness, pain and dyspareunia. This study aimed to investigate whether Low Level Laser Therapy can improve the quality of life in women with Lichen sclerosus and insufficient topical treatment. The study proposed a supplemental therapy to insufficient topical treatment in patients with Lichen sclerosus. This study indicated that Low Level Laser Therapy treatment can improve the quality of life in women with Lichen sclerosus.

Photodynamic therapy repairs medication-related osteonecrosis of the jaw by reducing NF-kB protein in rats.

OBJECTIVE: To evaluate whether antimicrobial photodynamic therapy (aPDT) repairs bisphosphonate-related osteonecrosis of the jaw (BRONJ) modulated by the reduction of NF-kB protein in a murine model. METHODOLOGY: Male Wistar rats (N=30) were divided into the following groups (n=6/group): negative control (NC); experimental osteonecrosis (ONE); ONE + photosensitizer (PS); ONE + photobiomodulation (PBM); and ONE + aPDT. Over 8 weeks, ONE was induced by zoledronic acid 250 µg/kg injections, except in the NC group, which received sterile 0.9% saline, followed by extraction of the lower left first molar. Red light laser irradiation (wavelength ~660 nm, power 50 mW, energy of 2 J, energy dose of 66.67 J/cm2 for 40 s) was performed once a week for 4 weeks. Methylene blue 0.3% was used as PS. The animals were euthanized and examined macroscopically for the presence of exposed bone and epithelial repair and microscopically by histochemical (hematoxylin-eosin and Masson's trichrome staining) and immunohistochemical (anti-NF-kB) methods. Macroscopic and histomorphometric data were analyzed by one-way ANOVA and Tukey's post-test (p<0.05). RESULTS: Mucosal repair, viable osteocytes, and NF-kB immunostaining were observed in the NC, ONE+PS, ONE+PBM, and ONE+aPDT groups. The ONE group showed no mucosal repair, showing empty lacunae and multifocal immunostaining for NF-kB. The ONE+PBM and ONE+aPDT groups had greater deposition of extracellular matrix and less necrotic bone tissue (p<0.05). CONCLUSION: PBM and aPDT treatments for BRONJ were effective for bone and epithelial repair, in addition to reducing inflammation mediated by the decrease of NF-kB protein in the irradiated regions.

Does electrophysical agents work for cellulite treatment? a systematic review of clinical trials.

Cellulite, a perceived alteration in skin topography, is predominantly found in adipose tissue-rich body regions such as the hips, buttocks, thighs, and abdomen. Contrary to common belief, the etiology and pathophysiology of cellulite are not well-established or universally agreed upon. This lack of understanding about the actual etiology of cellulite directly influences the selection of suitable treatments that can address both the aesthetic and inflammatory aspects of the condition. Various treatment methods, including electrophysical agents like electric currents, radiofrequency, ultrasound, and photobiomodulation, have been tested. However, the questionable methodological quality of many studies complicates the determination of effective treatments for cellulite. In this study, we conducted a systematic review of clinical studies that utilized electrophysical agents in cellulite treatment. METHODS: We employed the PICO (population, intervention, control, and outcome) process to develop our search strategy and establish inclusion/exclusion criteria. We searched five databases: Medline, Central, Scopus, Lilacs, and PEDro, for studies conducted between 2001 and July 2021 that involved cellulite treatment with electrophysical agents. To ensure systematicity and guide study selection, we adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. RESULTS: Our initial search yielded 556 articles: 379 from Medline, 159 from Central, and 18 from Lilacs. After applying our inclusion criteria, only 32 studies remained. Of these, only two (6.2%) were evaluated as having strong and good methodology via the QualSyst tool. CONCLUSIONS: Our findings indicate that the quality of evidence from clinical studies on the use of electrophysical agents for cellulite treatment remains subpar. Further studies with robust experimental designs and more precise assessment techniques are necessary. While our study does not refute the effectiveness of the techniques used for cellulite treatment, it underscores the need for additional well-designed trials.

[The impact of laser radiation on the effectiveness of therapeutic treatment of dental patients]. / Vliyanie lazernogo izlucheniya na effektivnost' terapevticheskogo lecheniya stomatologicheskikh bol'nykh.

The paper presents an overview of modern scientific data on the study of the effect of laser radiation on biological tissues of the mouth in the therapeutic treatment of dental diseases. The use of lasers in the treatment of dental caries and its complications, non-carious lesions of hard dental tissues, as well as the use of lasers in the treatment of periodontal diseases and aesthetic restoration of teeth is considered.

Directed physiological networks in the human prefrontal cortex at rest and post transcranial photobiomodulation.

Cerebral infra-slow oscillation (ISO) is a source of vasomotion in endogenic (E; 0.005-0.02 Hz), neurogenic (N; 0.02-0.04 Hz), and myogenic (M; 0.04-0.2 Hz) frequency bands. In this study, we quantified changes in prefrontal concentrations of oxygenated hemoglobin (Δ[HbO]) and redox-state cytochrome c oxidase (Δ[CCO]) as hemodynamic and metabolic activity metrics, and electroencephalogram (EEG) powers as electrophysiological activity, using concurrent measurements of 2-channel broadband near-infrared spectroscopy and EEG on the forehead of 22 healthy participants at rest. After preprocessing, the multi-modality signals were analyzed using generalized partial directed coherence to construct unilateral neurophysiological networks among the three neurophysiological metrics (with simplified symbols of HbO, CCO, and EEG) in each E/N/M frequency band. The links in these networks represent neurovascular, neurometabolic, and metabolicvascular coupling (NVC, NMC, and MVC). The results illustrate that the demand for oxygen by neuronal activity and metabolism (EEG and CCO) drives the hemodynamic supply (HbO) in all E/N/M bands in the resting prefrontal cortex. Furthermore, to investigate the effect of transcranial photobiomodulation (tPBM), we performed a sham-controlled study by delivering an 800-nm laser beam to the left and right prefrontal cortex of the same participants. After performing the same data processing and statistical analysis, we obtained novel and important findings: tPBM delivered on either side of the prefrontal cortex triggered the alteration or reversal of directed network couplings among the three neurophysiological entities (i.e., HbO, CCO, and EEG frequency-specific powers) in the physiological network in the E and N bands, demonstrating that during the post-tPBM period, both metabolism and hemodynamic supply drive electrophysiological activity in directed network coupling of the prefrontal cortex (PFC). Overall, this study revealed that tPBM facilitates significant modulation of the directionality of neurophysiological networks in electrophysiological, metabolic, and hemodynamic activities.

Unlocking the Power of Light on the Skin: A Comprehensive Review on Photobiomodulation.

Photobiomodulation (PBM) is a procedure that uses light to modulate cellular functions and biological processes. Over the past decades, PBM has gained considerable attention for its potential in various medical applications due to its non-invasive nature and minimal side effects. We conducted a narrative review including articles about photobiomodulation, LED light therapy or low-level laser therapy and their applications on dermatology published over the last 6 years, encompassing research studies, clinical trials, and technological developments. This review highlights the mechanisms of action underlying PBM, including the interaction with cellular chromophores and the activation of intracellular signaling pathways. The evidence from clinical trials and experimental studies to evaluate the efficacy of PBM in clinical practice is summarized with a special emphasis on dermatology. Furthermore, advancements in PBM technology, such as novel light sources and treatment protocols, are discussed in the context of optimizing therapeutic outcomes and improving patient care. This narrative review underscores the promising role of PBM as a non-invasive therapeutic approach with broad clinical applicability. Despite the need for further research to develop standard protocols, PBM holds great potential for addressing a wide range of medical conditions and enhancing patient outcomes in modern healthcare practice.

Clinical and ex-vivo effect of LASERs on prevention of early-enamel caries: systematic review & meta-analyses.

To investigate the in vivo and in situ effect of different types of lasers in prevention of enamel demineralization in high caries risk cases (around orthodontic brackets, around restoration and in caries susceptible pits and fissures). PubMed was searched using the following keyword sequence; (Laser therapy OR laser irradiation OR laser application) AND (enamel caries prevention OR enamel demineralization OR enamel remineralization OR early enamel caries OR early-enamel caries OR enamel resistance OR enamel decalcification OR white spot lesions WSLs OR incipient lesion OR enamel decay OR enamel Dissolution OR enamel microhardness) AND (clinical trial OR Randomized clinical trial OR In situ study). The latest literature search was ended by "30 January 2023". PubMed was used as a primary data base for study selection. Scopus, EBSCO, and Google scholar are checked in our study after results of systematic search on PubMed. Only duplicates were found. Two meta-analyses were carried out. The first, clinical meta-analysis on incidence of white spot lesions (WSLs) following CO2 laser irradiation of enamel. The second meta-analysis on ex-vivo/in situ effect of CO2 laser on microhardness of enamel. In each meta-analysis three studies were included. Risk of bias was assessed. The search identified eight studies (four ex-vivo and four clinical trials). Regarding the clinical meta-analysis, the overall standardized mean difference was 0.21 [ 95% confidence interval (CI): 0.15-0.30, p < 0.00001]. This indicates that the incidence of new WSLs in patients who received low power CO2 laser treatment was highly significantly lower than placebo groups. The heterogeneity was considerable (I2 = 71%). In the second meta-analysis, the overall standardized mean difference was 49.55 [ 95% confidence interval (CI): 37.74, 61.37, p < 0.00001]. This indicates that microhardness of enamel receiving low power (0.4-5 W) CO2 laser irradiation is highly significantly lower than control untreated enamel. The heterogeneity was substantial (I2 = 48%). Within the limitations of this study, Low level laser therapy concept with CO2 laser seems to be effective in preventing enamel caries.Prospero registration number: CRD42023437379.

Photobiomodulation in promoting increased Skin Flap Viability: a systematic review of animal studies.

Necrosis is common in skin flap surgeries. Photobiomodulation, a noninvasive and effective technique, holds the potential to enhance microcirculation and neovascularization. As such, it has emerged as a viable approach for mitigating the occurrence of skin flap necrosis. The aim of this systematic review was to examine the scientific literature considering the use of photobiomodulation to increase skin-flap viability. The preferred reporting items for systematic reviews and meta-analyses (PRISMA), was used to conducted systematic literature search in the databases PubMed, SCOPUS, Elsevier and, Scielo on June 2023. Included studies investigated skin-flap necrosis employing PBMT irradiation as a treatment and, at least one quantitative measure of skin-flap necrosis in any animal model. Twenty-five studies were selected from 54 original articles that addressed PBMT with low-level laser (LLL) or light-emitting diode (LED) in agreement with the qualifying requirements. Laser parameters varied markedly across studies. In the selected studies, the low-level laser in the visible red spectrum was the most frequently utilized PBMT, although the LED PBMT showed a similar improvement in skin-flap necrosis. Ninety percent of the studies assessing the outcomes of the effects of PBMT reported smaller areas of necrosis in skin flap. Studies have consistently demonstrated the ability of PBMT to improve skin flap viability in animal models. Evidence suggests that PBMT, through enhancing angiogenesis, vascular density, mast cells, and VEGF, is an effective therapy for decrease necrotic tissue in skin flap surgery.

Evaluation of the effect of different kinds of treatment modalities for temporomandibular joint pain and its relevance to chronic cervical pain: A randomized controlled trial.

AIM: The aim of this study was to evaluate the effect of different treatment modalities for temporomandibular joint (TMJ) pain and their relevance to chronic cervical pain after 12 months. SETTINGS AND DESIGN: This was a randomized controlled trial. MATERIALS AND METHODS: Forty-eight participants with chronic cervical and TMJ pain were selected using research diagnostic criteria and randomized into four groups (n = 12), which included control, soft splints, transcutaneous electrical nerve stimulation (TENS), and low-level laser (LLL). The cervical and TMJ pain was recorded using visual analog scale (VAS) scores at baseline, 3 months, 6 months, and 12 months. Occlusal equilibration was done for all groups except for the control. STATISTICAL ANALYSIS USED: The mean pain scores were statistically analyzed using one-way analysis of variance and posthoc test. RESULTS: The mean VAS scores in TMJ pain patients between the four groups at baseline and at final follow-up were 7.27 ± 1.29 in Group 1, 7.53 ± 0.70 in Group 2, 7.76 ± 0.80 in Group 3, and 7.61 ± 0.61 in Group 4. The mean difference between Groups 1 and 3, Groups 1 and 4, and Groups 2 and 3 was statistically significant (P < 0.00). Pearson correlation test yielded a mild and negative correlation between TMJ and cervical pain. CONCLUSION: TENS and LLL were found to be equally effective in reducing pain in the jaw joint region, followed by soft splints, and there was no correlation between TMJ and cervical pain.

Photobiomodulation Can Prevent Medication-Related Osteonecrosis of the Jaw Formation in Tooth Extraction Site of Rat Model.

Objective: This study aims to explore the preventive potential of photobiomodulation (PBM) in bisphosphonate-related osteonecrosis of the jaw (BRONJ) using a rat model. Methods: An experimental rat model was established, exposing rats to zoledronic acid (ZA), a primary risk factor for BRONJ. An 810 nm diode laser was applied with parameters of 0.33 W/cm2 power density and 10 J/cm2 energy density for 30 sec. PBM was initiated 1 day pre-extraction and continued for 2 weeks. The impact of PBM on wound healing in both soft and hard tissues was evaluated post tooth extraction. Results: ZA exposure hindered wound healing in both soft and hard tissues after tooth extraction. PBM intervention effectively mitigated the adverse effects of ZA, promoting healing processes in both tissue types. This suggests the potential of PBM as a preventive strategy for BRONJ in patients on long-term bisphosphonate treatment. Moreover, PBM exhibited enhanced wound healing in normal rats, indicating its broader applicability beyond BRONJ cases. Conclusions: PBM shows promise in preventing and improving wound healing in BRONJ and normal cases. These findings underscore the significance of optimizing PBM parameters and suggest its potential clinical relevance as a preventive intervention for BRONJ and a promoter of wound healing.

The Efficiency of Erbium Lasers in the Removal of Root Canal System and Surface Biofilms: A Systematic Review and Meta-Analysis.

Background: Studies have shown positive effects of erbium lasers in removal of biofilms. A review article was required with quantitative data for confirmation of their effects, but there is still no a comprehensive study reviewing their effects based on the root canal and implant surface. This systematic review and meta-analysis was conducted to evaluate the efficiency of erbium lasers in removal of the root canal system and surface biofilms. Methods: Studies were searched with keywords in databases of PubMed, Scopus, Europe PMC, Cochrane Central, Embase, and Web of Science and screened by referees. Data were included based on mean ± standard deviation and size of control and laser groups. Effect sizes were assessed as standardized mean differences and calculated for each study and for the root and dental surface. Laser characteristics and bacteria were considered as moderators. Results: Nineteen articles in the current study comprised 565 samples (283 control samples and 282 laser samples). The analyses showed the significant effects of erbium lasers on bacterial biofilms on the implant surface [-0.496, 95% confidence interval, CI (-0.720 to -0.273); I2 = 26.94; p = 0.029; Q = 13.28] and root canal [-0.551, 95% CI (-0.656 to -0.445); I2 = 23.89; p = 0.031; Q = 10.46]. Results showed that highest efficiency lasers were obtained at higher wavelengths of 2940 nm, 75-100 mJ energy, and 100-150 µsec and <50-Hz pulses. Conclusions: Erbium lasers can be used to remove biofilms on dental implant surfaces and root canal systems and are safe options for untouchable sites in the root canal.

Photobiomodulation therapy moderates cancer cachexia-associated muscle wasting through activating PI3K/AKT/FoxO3a pathway.

Cancer cachexia-associated muscle wasting as a multifactorial wasting syndrome, is an important factor affecting the long-term survival rate of tumor patients. Photobiomodulation therapy (PBMT) has emerged as a promising tool to cure and prevent many diseases. However, the effect of PBMT on skeletal muscle atrophy during cancer progression has not been fully demonstrated yet. Here, we found PBMT alleviated the atrophy of myotube diameter induced by cancer cells in vitro, and prevented cancer-associated muscle atrophy in mice bearing tumor. Mechanistically, the alleviation of muscle wasting by PBMT was found to be involved in inhibiting E3 ubiquitin ligases MAFbx and MuRF-1. In addition, transcriptomic analysis using RNA-seq and GSEA revealed that PI3K/AKT pathway might be involved in PBMT-prevented muscle cachexia. Next, we showed the protective effect of PBMT against muscle cachexia was totally blocked by AKT inhibitor in vitro and in vivo. Moreover, PBMT-activated AKT promoted FoxO3a phosphorylation and thus inhibiting the nucleus entry of FoxO3a. Lastly, in cisplatin-treated muscle cachexia model, PBMT had also been shown to ameliorate muscle atrophy through enhancing PI3K/AKT pathway to suppress MAFbx and MuRF-1 expression. These novel findings revealed that PBMT could be a promising therapeutic approach in treating muscle cachexia induced by cancer.

A retrospective study of cumulative absolute reduction in axial length after photobiomodulation therapy.

BACKGROUND: To assess the age and timeline distribution of ocular axial length shortening among myopic children treated with photobiomodulation therapy in the real world situations. METHODS: Retrospective study of photobiomodulation therapy in Chinese children aged 4 to 13 years old where axial length measurements were recorded and assessed to determine effectiveness at two age groups (4 ∼ 8 years old group and 9 ∼ 13 years old group). Data was collected from myopic children who received photobiomodulation therapy for 6 ∼ 12 months. Effectiveness of myopia control was defined as any follow-up axial length ≤ baseline axial length, confirming a reduction in axial length. Independent t-test was used to compare the effectiveness of the younger group and the older group with SPSS 22.0. RESULTS: 342 myopic children were included with mean age 8.64 ± 2.20 years and baseline mean axial length of 24.41 ± 1.17 mm. There were 85.40%, 46.30%, 71.20% and 58.30% children with axial length shortening recorded at follow-up for 1 month, 3 months, 6 months and 12 months, respectively. With respect to the axial length shortened eyes, the mean axial length difference (standard deviation) was - 0.039 (0.11) mm, -0.032 (0.11) mm, -0.037 (0.12) mm, -0.028 (0.57) mm at 1, 3, 6, and 12-month follow-up, respectively. Greater AL shortening was observed among the older group who had longer baseline axial lengths than the younger group (P < 0.001). CONCLUSIONS: Overall myopia control effectiveness using photobiomodulation therapy was shown to be age and time related, with the maximum absolute reduction in axial elongation being cumulative.

Photobiomodulation therapy in improvement of harmful neural plasticity in sodium salicylate-induced tinnitus.

Tinnitus is a common annoying symptom without effective and accepted treatment. In this controlled experimental study, photobiomodulation therapy (PBMT), which uses light to modulate and repair target tissue, was used to treat sodium salicylate (SS)-induced tinnitus in a rat animal model. Here, PBMT was performed simultaneously on the peripheral and central regions involved in tinnitus. The results were evaluated using objective tests including gap pre-pulse inhibition of acoustic startle (GPIAS), auditory brainstem response (ABR) and immunohistochemistry (IHC). Harmful neural plasticity induced by tinnitus was detected by doublecortin (DCX) protein expression, a known marker of neural plasticity. PBMT parameters were 808 nm wavelength, 165 mW/cm2 power density, and 99 J/cm2 energy density. In the tinnitus group, the mean gap in noise (GIN) value of GPIAS test was significantly decreased indicated the occurrence of an additional perceived sound like tinnitus and also the mean ABR threshold and brainstem transmission time (BTT) were significantly increased. In addition, a significant increase in DCX expression in the dorsal cochlear nucleus (DCN), dentate gyrus (DG) and the parafloccular lobe (PFL) of cerebellum was observed in the tinnitus group. In PBMT group, a significant increase in the GIN value, a significant decrease in the ABR threshold and BTT, and also significant reduction of DCX expression in the DG were observed. Based on our findings, PBMT has the potential to be used in the management of SS-induced tinnitus.

Devices used for photobiomodulation of the brain-a comprehensive and systematic review.

A systematic review was conducted to determine the trends in devices and parameters used for brain photobiomodulation (PBM). The revised studies included clinical and cadaveric approaches, in which light stimuli were applied to the head and/or neck. PubMed, Scopus, Web of Science and Google Scholar databases were used for the systematic search. A total of 2133 records were screened, from which 97 were included in this review. The parameters that were extracted and analysed in each article were the device design, actuation area, actuation site, wavelength, mode of operation, power density, energy density, power output, energy per session and treatment time. To organize device information, 11 categories of devices were defined, according to their characteristics. The most used category of devices was laser handpieces, which relate to 21% of all devices, while 28% of the devices were not described. Studies for cognitive function and physiological characterisation are the most well defined ones and with more tangible results. There is a lack of consistency when reporting PBM studies, with several articles under defining the stimulation protocol, and a wide variety of parameters used for the same health conditions (e.g., Alzheimer's or Parkinson's disease) resulting in positive outcomes. Standardization for the report of these studies is warranted, as well as sham-controlled comparative studies to determine which parameters have the greatest effect on PBM treatments for different neurological conditions.