Comparison of photobiomodulation using either an intraoral or an extraoral laser on oral mucositis induced by chemotherapy in rats

Development and Application of Prototype System Based on Light-Emitting Diode Arrays (660 nm) with a Top Hat Beam Profile in Order to Optimize Photobiomodulation Protocols for Treatment of Radiation-Induced Oral Mucositis in Rats

Background: Oral mucositis (OM) is a common adverse effect of radiation to the head and neck. Recent research has shown that extra oral photobiomodulation (EO-PBM) reduces the severity of OM. However, appropriate EO-PBM therapy parameters for OM severity reduction have not been documented. Objective: This work aims to optimize EO-PBM radiation parameters for lowering the severity of radiation-induced OM in rats by establishing a photobiomodulation (PBM) treatment system based on light-emitting diode arrays with top-hat beam profile. Methods: The 36 rats are separated into 2 control groups and 4 groups receiving PBM treatment. The PBM groups are exposed to irradiance between 4 and 24 J/cm2 at 660 nm. The cheek pouch mucosa is removed after scarification for biochemical and histological examination. Student's t-test, and one-way analysis of variance (ANOVA) followed by Tukey's Multiple were applied to compare the statistical significance of differences between control groups and PBM treatment groups. Results: Statistical analysis reveals that PBM irradiation at 12 J/cm2 (200 sec) with a flatness of 0.8 and a diameter of 3 cm substantially decreased the level of inflammatory cytokines compared with the positive control group. Conclusions: Our results indicate that the designed treatment PBM system is capable of delivering the optical parameters necessary for therapeutic treatment.

Proposal of a prophylactic photobiomodulation protocol for chemotherapy-induced oral and oropharyngeal mucositis: a randomized clinical trial

Photobiomodulation therapy (PBMT) is widely used in oncology settings, but lack of assessment standardization is the main barrier to optimization of clinical protocols. This study analyzed three PBMT protocols for preventing oral and oropharyngeal mucositis (OM) in patients undergoing chemotherapy (CT) and/or hematopoietic stem cell transplantation (HSCT). This is a preliminary randomized blind clinical trial. Group 1 received intraoral prophylactic PBMT, Group 2 received intraoral and oropharyngeal PBMT, and Group 3 received intraoral, oropharyngeal, and extraoral PBMT. The applications were from the first day of CT to day + 10. Clinicodemographic data, CT regimens, types of HSCT, hematological exams, occurrence/severity of OM, odynophagia, and OM-related opportunistic infections were assessed. Sixty participants (age range: 18-74 years) were included; 70% of them underwent CT and 30% HSCT. About 43.3% of patients had OM, while odynophagia was reported by 23.3%. Both Groups 1 and 2 revealed better results. Multivariate analysis showed that HSCT directly influenced the occurrence of OM. Individuals who had undergone allogeneic HSCT were 1.93 times more likely to develop OM (p < 0.001). Group 3 exhibited a higher frequency of OM, albeit of lower grades. This group consisted of half the population who had undergone HSCT, had the highest percentage of melphalan use, and had the lowest mean leukocyte count. The three proposed protocols were effective in preventing and reducing OM, with good tolerance and no reported adverse effects. PBMT is a safe and effective approach to OM prophylaxis in adults undergoing CT/HSCT.

Experimental Chemotherapy-Induced Mucositis: A Scoping Review Guiding the Design of Suitable Preclinical Models

Mucositis is a common and most debilitating complication associated with the cytotoxicity of chemotherapy. The condition affects the entire alimentary canal from the mouth to the anus and has a significant clinical and economic impact. Although oral and intestinal mucositis can occur concurrently in the same individual, these conditions are often studied independently using organ-specific models that do not mimic human disease. Hence, the purpose of this scoping review was to provide a comprehensive yet systematic overview of the animal models that are utilised in the study of chemotherapy-induced mucositis. A search of PubMed/MEDLINE and Scopus databases was conducted to identify all relevant studies. Multiple phases of filtering were conducted, including deduplication, title/abstract screening, full-text screening, and data extraction. Studies were reported according to the updated Preferred Reporting Items for Systematic reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. An inter-rater reliability test was conducted using Cohen's Kappa score. After title, abstract, and full-text screening, 251 articles met the inclusion criteria. Seven articles investigated both chemotherapy-induced intestinal and oral mucositis, 198 articles investigated chemotherapy-induced intestinal mucositis, and 46 studies investigated chemotherapy-induced oral mucositis. Among a total of 205 articles on chemotherapy-induced intestinal mucositis, 103 utilised 5-fluorouracil, 34 irinotecan, 16 platinum-based drugs, 33 methotrexate, and 32 other chemotherapeutic agents. Thirteen articles reported the use of a combination of 5-fluorouracil, irinotecan, platinum-based drugs, or methotrexate to induce intestinal mucositis. Among a total of 53 articles on chemotherapy-induced oral mucositis, 50 utilised 5-fluorouracil, 2 irinotecan, 2 methotrexate, 1 topotecan and 1 with other chemotherapeutic drugs. Three articles used a combination of these drugs to induce oral mucositis. Various animal models such as mice, rats, hamsters, piglets, rabbits, and zebrafish were used. The chemotherapeutic agents were introduced at various dosages via three routes of administration. Animals were mainly mice and rats. Unlike intestinal mucositis, most oral mucositis models combined mechanical or chemical irritation with chemotherapy. In conclusion, this extensive assessment of the literature revealed that there was a large variation among studies that reproduce oral and intestinal mucositis in animals. To assist with the design of a suitable preclinical model of chemotherapy-induced alimentary tract mucositis, animal types, routes of administration, dosages, and types of drugs were reported in this study. Further research is required to define an optimal protocol that improves the translatability of findings to humans.

Effects of different protocols of defocused high-power laser on the viability and migration of myoblasts-a comparative in vitro study

The aim of the present study was to analyze for the first time the effect of photobiomodulation therapy (PBMT) using defocused high-power laser (DHPL) in myoblast cell line C2C12 viability and migration and compare them with low-power laser therapy. Cells were divided into 9 groups: Sham irradiation 10% fetal bovine serum (FBS); Sham irradiation 5%FBS; low-power laser 0.1 W; DHPL 810 1 W; DHPL 810 2 W; DHPL 980 1 W; DHPL 980 2 W; DHPL dual 1 W; DHPL dual 2 W. To simulate stress conditions, all groups exposed to irradiation were maintained in DMEM 5% FBS. The impact of therapies on cell viability was assessed through sulforhodamine B assay and on cells migration through scratch assays and time-lapse. Myoblast viability was not modified by PBMT protocols. All PBMT protocols were able to accelerate the scratch closure after 6 and 18 h of the first irradiation (p < 0.001). Also, an increase in migration speed, with a more pronounced effect of DHPL laser using dual-wavelength protocol with 2 W was observed (p < 0.001). In conclusion, the diverse PBMT protocols used in this study accelerated the C2C12 myoblasts migration, with 2-W dual-wavelength outstanding as the most effective protocol tested. Benefits from treating muscle injuries with PBMT appear to be related to its capacity to induce cell migration without notable impact on cell viability.

Oxidative Stress and Chemoradiation-Induced Oral Mucositis: A Scoping Review of In Vitro, In Vivo and Clinical Studies

Chemoradiation-induced mucositis is a debilitating condition of the gastrointestinal tract eventuating from antineoplastic treatment. It is believed to occur primarily due to oxidative stress mechanisms, which generate Reactive Oxygen Species (ROS). The aim of this scoping review was to assess the role of oxidative stress in the development of Oral Mucositis (OM). Studies from the literature, published in MEDLINE and SCOPUS, that evaluated the oxidative stress pathways or antioxidant interventions for OM, were retrieved to elucidate the current understanding of their relationship. Studies failing inclusion criteria were excluded, and those suitable underwent data extraction, using a predefined data extraction table. Eighty-nine articles fulfilled criteria, and these were sub-stratified into models of study (in vitro, in vivo, or clinical) for evaluation. Thirty-five clinical studies evaluated antioxidant interventions on OM's severity, duration, and pain, amongst other attributes. A number of clinical studies sought to elucidate the protective or therapeutic effects of compounds that had been pre-determined to have antioxidant properties, without directly assessing oxidative stress parameters (these were deemed "indirect evidence"). Forty-seven in vivo studies assessed the capacity of various compounds to prevent OM. Findings were mostly consistent, reporting reduced OM severity associated with a reduction in ROS, malondialdehyde (MDA), myeloperoxidase (MPO), but higher glutathione (GSH) and superoxide dismutase (SOD) activity or expression. Twenty-one in vitro studies assessed potential OM therapeutic interventions. The majority demonstrated successful a reduction in ROS, and in select studies, secondary molecules were assessed to identify the mechanism. In summary, this review highlighted numerous oxidative stress pathways involved in OM pathogenesis, which may inform the development of novel therapeutic targets.

The Path to an Evidence-Based Treatment Protocol for Extraoral Photobiomodulation Therapy for the Prevention of Oral Mucositis

Oral mucositis is a painful complication of hematopoietic stem cell transplantation for which photobiomodulation therapy (PBMT) is a safe and effective intervention. Extraoral delivery of PBMT has clinical advantages over intraoral delivery but requires additional dosimetric considerations due to the external tissue layers through which the light must propagate before reaching the oral mucosa. Additionally, to date there has been no dose modeling study, a task essential to developing a justified treatment protocol. We review here some of the complexities surrounding extraoral photobiomodulation therapy and offer that may help guide researchers toward an evidence-based treatment protocol for the prevention of oral mucositis.

Comparative study of royal jelly, propolis, and photobiomodulation therapies in 5-fluorouracil-related oral mucositis in rats

PURPOSE

This study aimed to evaluate the effects and mechanisms of action of royal jelly (RJ) and propolis compared to photobiomodulation therapy (PBMT) in an animal model of 5-fluorouracil-related oral mucositis (OM).

METHODS

Seventy-two male Wistar rats were randomly allocated to four groups (n = 18 each): control (no treatment), PBMT (intraoral laser, 6 J/cm²), RJ, and propolis. On days 0 and 2, the animals received an injection of 5-fluorouracil (5-FU). The buccal mucosa was scratched (days 3 and 4) and the treatments were initiated on day 5. Six animals of each group were euthanized on days 8, 10, and 14. Phytochemical analysis (thin-layer chromatography, TLC) and clinical, histopathological, and immunohistochemical analysis of pS6, pAKT, and NF-κB were performed, and oxidative stress markers were also investigated.

RESULTS

TLC revealed the presence of large amounts of sucrose (Rf 0.34) in RJ and of flavonoids in propolis. Lower clinical OM scores were observed on day 8, and improved morphological data were observed on day 10 in the PBMT, RJ, and propolis groups (p < 0.05). On day 8, immunoexpression of pS6, pAKT, and NF-κB was increased compared to control. On day 14, reduced glutathione (GSH) antioxidant levels were increased in the propolis group compared to control (p < 0.05).

CONCLUSIONS

Our results showed that RJ and propolis, as well as PBMT, are effective in the treatment of OM. Considering that some patients who develop OM do not have access to PBMT, the present study demonstrated that topical application of RJ and propolis may be an important alternative for the treatment of OM.

Defocused high-power diode laser accelerates skin repair in a murine model through REDOX state modulation and reepithelization and collagen deposition stimulation

Skin wounds represent a burden in healthcare. Our aim was to investigate for the first time the effects of defocused high-power diode laser (DHPL) on skin healing in an animal experimental model and compare it with gold standard low-level laser therapy. Male Wistar rats were divided into 5 groups: Negative control; Sham; 0.1 W laser (L0.1 W); DHPL Dual 1 W (DHPLD1 W); and DHPL Dual 2 W (DHPLD2 W). Rats were euthanized on days 3, 5, 10, 14 and 21. Clinical, morphological, PicroSirus, oxidative stress (MDA, SOD and GSH) and cytokines (IL-1β, IL-10 and TNF-α) analyses were performed. A faster clinical repair was observed in all laser groups at D10 and D14. DHPLD1 W exhibited lower inflammation and better reepithelization compared to other groups at D10. DHPL protocols modulated oxidative stress by decreasing MDA and increasing SOD and GSH. Collagen maturation was triggered by all protocols tested and L0.1 W modulated cytokines release (IL-1β and TNF-α) at D3. In conclusion, DHPL, especially DHPL1 W protocol, accelerated skin healing by triggering reepithelization and collagen maturation and modulating inflammation and oxidative stress.

Treatment Parameters of Photobiomodulation in the Prevention of Non-surgical Cancer Treatment-Induced Oral Mucositis: A Review of Preclinical Studies

Introduction: The most important side effect after non-surgery cancer treatment (NSCT) is oral mucositis (OM) which degrades the quality of life. Using photobiomodulation (PBM), formerly known as low-level laser therapy (LLLT), in the prevention of NSCT-induced OM was widely studied. Hence, this review evaluates the efficacy of optical treatment parameters behind the working process of PBM in preventing NSCT-induced OM in preclinical studies. Methods: Using the PubMed, Scopus and Embase databases, the present study systematically reviewed existing preclinical studies for optical treatment parameters of PBM in preventing NSCT-induced OM in experimental models without restriction on the year of publication. Results: In total, 51 articles were recognized during the search of the literature, and only 16 research papers were included in this review, taking into consideration the inclusion as well as exclusion benchmarks. The reviewed studies showed that a consensus has yet to be reached on the optimal PBM treatment parameters in preventing NSCT-induced OM. However, a wavelength of 660 nm, a power density of 40 mW as well as fluence which ranged between 2 and 6 J/cm2 were mostly utilized in the included studies. Furthermore, the severity of NSCT-induced OM was reduced following PBM application with no reported severe side effects. Conclusion: The efficacy of PBM with the associated optical parameters is a promising strategy in preventing NSCT-induced OM. However, the optimal parameters of PBM need to be investigated.

Intraoral versus extraoral photobiomodulation therapy in the prevention of oral mucositis in HSCT patients: a randomized, single-blind, controlled clinical trial

To compare the efficacy of intraoral and extraoral photobiomodulation (PBM) protocols for the prevention of oral mucositis (OM) in hematopoietic stem cell transplantation (HSCT) patients. A total of 60 patients was randomized into intraoral PBM (IOPBM) and extraoral PBM (EOPBM) groups. Both PBM protocols were well tolerated and no side effects were observed. EOPBM session times were one fourth of IOPBM durations. Of 60 patients, 35 (58.3%) developed ulcerated OM between day +3 and day +12. No intergroup difference was observed in OM healing times (p = 0.424). The lateral border of the tongue was the most common site affected in both groups. However, the incidence of mucositis on buccal mucosa was significantly reduced in the EOPBM group (p = 0.021). Young patients (OR.5.35, 95%CI 0.94-30.4, p = 0.058) and those who had received myeloablative conditioning (OR.55.1, 95%CI 2.69-1129.3, p = 0.009) were more likely to develop ulcerated OM, whereas autologous HSCT recipients (OR 0.079, 95% CI 0.009-0.67, p = 0.021) had a lower probability of developing ulcerated OM independent of PBM protocol. EOPBM protocol was as effective as IOPBM in the management of OM in HSCT patients, with the advantage of shorter treatment sessions. Trial registration number: RBR-7nww56. Date of trial registration submission: 30th September 2019.

Effectiveness of phytotherapeutics in the prevention and treatment of 5-fluorouracil-induced oral mucositis in animal models: A systematic review

OBJECTIVES

This systematic review evaluated the effect of phytotherapeutics in the treatment and prevention of 5-fluorouracil (5-FU)-induced oral mucositis (OM) in animal models.

DESIGN

A search was performed in PubMed/Medline, CENTRAL (The Cochrane Library), EMBASE, and Web of Science, including studies published up to January 2020. Only articles investigating the chemoinduction of OM by 5-FU in animal models were included. Eligibility was evaluated and data were extracted from the eligible studies following the predefined PICO questions. The Cochrane Collaboration Risk of Bias Assessment tool was used to evaluate the quality of the included studies.

RESULT

A total of 503 articles were retrieved and 13 were included. The hamster was the animal model used in all included studies. The treatment method ranged from the topical application of ointment (n = 3), gel (n = 5) and extract (n = 3) to the oral ingestion of the phytotherapeutics (n = 3). Chamomilla recutita L. (n = 3) and Pistacia atlantica (n = 3) were the most used therapeutic agents. Although all studies were classified as high risk of bias, all of them reported promising results regarding the use of phytotherapeutics in the management of OM, including lower clinical and histopathological scores as well as healing, anti-inflammatory, antimicrobial, and antioxidant activities.

CONCLUSION

Despite the high risk of bias of the studies, phytotherapy is a promising alternative for the treatment of 5-FU-induced OM, showing interesting results in terms of tissue healing and anti-inflammatory, antimicrobial and antioxidant activity.