Oral Mucositis In Mice Research Articles

Abstract 6036: Flash proton radiotherapy mitigates radiation-induced salivary gland dysfunction and oral mucositis in mice

Abstract Background- Recent studies have reported that ultra-high dose rate “FLASH” Proton radiation therapy (F-PRT) decreases normal tissue toxicity while maintaining tumor-controlling efficacy compared to Standard Proton RT (S-PRT), that are used for patient treatments. However, although highly efficacious in eliminating tumors, damage to the otherwise healthy salivary glands and oral mucosa is often unavoidable in patients with head and neck cancer, leaving patients with lifelong xerostomia and other comorbidities. Aim- In this study, we aimed to investigate the effect of F-PRT on radiation-induced oral mucositis and salivary gland dysfunction and in controlling orthotopic tumor growth. Methods- The head and neck area of C57Bl/6 mice was irradiated with a single dose of 16 Gy or a fractionated dose of 8 Gy x 3 of F-PRT (128Gy/s) or S-PRT (0.95 Gy/s). Oral mucositis was analyzed by histopathological examination. Radiation-induced xerostomia was studied by measuring the saliva flow rate of mice. To examine the ability of F-PRT to control orthotopic head and neck tumors, tongue tumors were generated in mice and then irradiated with F-PRT/S-PRT. Results- Following irradiation with a single dose or a fractionated dose, saliva flow was reduced by both treatments. However, the F-PRT-treated mice showed a significant improvement in salivary flow at 14 days (p<0.05) and 28 days (p<0.005) post irradiation. Expression of AQP5 was found to be significantly down-regulated at 2, 5, 10, and 14 days post irradiation with S-PRT. However, mice irradiated with F-PRT showed a significant restoration of the AQP5 expression post-RT. Oral mucositis started to appear on day 14, which showed more severity on day 28 post-irradiation with S-PRT. Histopathological analysis showed the presence of lingual gland atrophy only in the tongue of mice treated with S-PRT 28 and 60 days post-irradiation. F-PRT ameliorates radiation-induced jawbone loss compared to S-PRT as observed in mice irradiated either with a single dose or in a fractionated regime. The surviving fraction of F-PRT-treated mice with orthotopic tongue tumors was significantly ameliorated compared to S-PRT-treated mice. Conclusion- This study demonstrates that F-PRT minimizes radiation-induced normal tissue toxicity after irradiation in mice’s head and neck region. Moreover, the ability of F-PRT to control orthotopic head and neck tumors further determines the efficacy of this modality for clinical applications. Citation Format: Priyanka Chowdhury, Anastasia Velalopoulou, Ioannis Verginadis, George Morcos, Michele Kim, James Metz, Lei Dong, Alexander Lin, Constantinos Koumenis. Flash proton radiotherapy mitigates radiation-induced salivary gland dysfunction and oral mucositis in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6036.

In vitro cytoprotective and in vivo anti-oral mucositis effects of melatonin and its derivatives.

According to our preliminary study, melatonin and its N-amide derivatives (N-(2-(1-4-bromobenzoyl-5-methoxy-1H-indol-3-yl)ethyl)acetamide (BBM) and 4-bromo-N-(2-(5-methoxy-1H-indol-3-yl)ethyl)benzamide (EBM)) inhibited the marker of acute inflammation in tests in vitro and in vivo. The anti-inflammatory agent is intended for the prevention and treatment of chemotherapy-induced toxicity. In this study aimed to evaluate the effect of melatonin and its derivatives on mechanisms related to chemotherapy-induced oral mucositis by in vitro ROS and 5-FU-induced human keratinocyte cells as well as in vivo oral mucositis model. In in vitro H2O2-induced HaCaT cells, BBM had the highest level of protection (34.57%) at a concentration 50 µM, followed by EBM (26.41%), and melatonin (7.9%). BBM also protected cells against 5-FU-induced to 37.69-27.25% at 12.5-100 µM while EBM was 36.93-29.33% and melatonin was 22.5-11.39%. In in vivo 5-FU-induced oral mucositis in mice, melatonin, BBM, and EBM gel formulations protected tissue damage from 5-FU similar to the standard compound, benzydamine. Moreover, the weight of mice and food consumption recovered more quickly in the BBM group. These findings suggested that it was possible to develop BBM and EBM as new therapeutic agents for the treatment of oral mucositis.

Therapeutic Intervention Using a Smad7-Based Tat Protein to Treat Radiation-Induced Oral Mucositis

Recent studies reported therapeutic effects of Smad7 on oral mucositis in mice without compromising radiation therapy-induced cancer cell killing in neighboring oral cancer. This study aims to assess whether a Smad7-based biologic can treat oral mucositis in a clinically relevant setting by establishing an oral mucositis model in dogs and analyzing molecular targets. We created a truncated human Smad7 protein fused with the cell-penetrating Tat tag (Tat-PYC-Smad7). We used intensity modulated radiation therapy to induce oral mucositis in dogs and applied Tat-PYC-Smad7 to the oral mucosa in dose-finding studies after intensity modulated radiation therapy. Clinical outcomes were evaluated. Molecular targets were analyzed in biopsies and serum samples. Tat-PYC-Smad7 treatment significantly shortened the duration of grade 3 oral mucositis based on double-blinded Veterinary Radiation Therapy Oncology Group scores and histopathology evaluations. Topically applied Tat-PYC-Smad7 primarily penetrated epithelial cells and was undetectable in serum. NanoString nCounter Canine IO Panel identified that, compared to the vehicle samples, top molecular changes in Tat-PYC-Smad7 treated samples include reductions in inflammation and cell death and increases in cell growth and DNA repair. Consistently, immunostaining shows that Tat-PYC-Smad7 reduced DNA damage and neutrophil infiltration with attenuated TGF-β and NFκB signaling. Furthermore, IL-1β and TNF-α were lower in Tat-PYC-Smad7 treated mucosa and serum samples compared to those in vehicle controls. Topical Tat-PYC-Smad7 application demonstrated therapeutic effects on oral mucositis induced by intensity modulated radiation therapy in dogs. The local effects of Tat-PYC-Smad7 targeted molecules involved in oral mucositis pathogenesis as well as reduced systemic inflammatory cytokines.

Protective Effect of Quercetin Nanoemulsion on 5-Fluorouracil-Induced Oral Mucositis in Mice.

The target of this study was to evaluate the efficacy, histopathological, oxidative stress, and molecular effects of quercetin (QRC) in mice with oral mucositis induced by 5-fluorouracil (5-FU). Thirty-six albino male mice with oral mucositis induced by 5-FU as a chemotherapeutic agent were used in this study. The animals were randomly divided into 6 groups: control group, mucositis (MUC) group, pretreatment group, posttreatment group, and two last groups including nanoemulsion form of QRC with a dose of 5 mg/kg in both pretreatment and posttreatment. In the present evaluation, fewer oral lesions were observed in the QRC posttreatment groups compared to the pretreatment and nanoemulsion receiving groups. In the SOD assay, the most significant difference was observed in the posttreatment nanogroup (41.073 ± 1.24) and pretreatment nanogroup (43.453 ± 2.60) in comparison to the 5-FU group (30.897 ± 1.93). The results of CAT assay also showed a significant difference in nano-posttreatment (124.60 ± 10.85), posttreatment (135.4 ± 9.82), and nano-pretreatment groups (128.80 ± 7.20) compared to the 5-FU group (55.07 ± 8.91). The expression of inflammatory genes such as Hif-1α and NfκB in this group was lower than in the other groups, although this difference was not significant. It seems that the use of QRC can improve the treatment process of oral mucositis induced by 5-FU.

Probiotic Streptococcus salivarius K12 Alleviates Radiation-Induced Oral Mucositis in Mice.

BackgroundOral mucositis is the most common oral complication of cancer patients receiving radiotherapy and/or chemotherapy, leading to poor quality of life. Limitations of the current interventions on radiation-induced oral mucositis (RIOM) urge the development of novel therapeutics. Here, we evaluated the treatment outcome of probiotic Streptococcus salivarius K12 on RIOM mice, and oral microbiota that is associated with the progress of RIOM was further investigated.MethodsAn experimental RIOM mouse model was established, and S. salivarius K12 was applied to the mouse oral cavity daily. Histological analyses were performed to evaluate the severity of oral mucositis and the treatment outcome of S. salivarius K12. The oral microbiota of mice was further analyzed by 16S rRNA sequencing, microbial culture and qPCR.Results Irradiation induced conspicuous mucositis in the oral cavity of mice. S. salivarius K12 treatment was beneficial for the healing of RIOM, as reflected by reduced ulcer size, increased basal layer epithelial cellularity and mucosal thickness, and elevated epithelial proliferation and attenuated apoptosis. RIOM mice presented significant oral microbial dysbiosis, with an overgrowth of oral anaerobes. S. salivarius K12 treatment reconstituted the oral microbiota and decreased the abundance of oral anaerobes of RIOM mice. In addition, S. salivarius K12 treatment inhibited NI1060 in Pasteurella genus and downregulated the expression of nitrate reductase.Conclusions S. salivarius K12 treatment can alleviate RIOM and reconstituted the dysbiotic oral microbiota in mice. S. salivarius K12 may represent a promising adjuvant treatment to improve the quality of life of cancer patients receiving radiotherapy.

GM-1111 reduces radiation-induced oral mucositis in mice by targeting pattern recognition receptor-mediated inflammatory signaling.

PurposeOral mucositis (OM) is a common, painful side effect of radiation therapy used for the treatment of head and neck cancer (HNC). Activation of the innate immune system upon irradiation has been identified as a key precipitating event of OM. To better understand OM’s pathogenesis, we studied pattern recognition receptors (PRRs) and their downstream pro-inflammatory cytokines in a mouse model of radiation-induced OM. We also tested therapeutic efficacy of GM-1111 that targets innate immune system to reduce radiation-induced OM.Methods and materialsThe pathogenesis of OM was studied in a single X-ray induced mouse model. The severity of OM was measured by visual and microscopical examinations. The irradiation-induced changes of PRRs and their downstream effector cytokine gene expression levels were determined. The efficacy of GM-1111 to reduce OM was tested in single and fractionated irradiation mouse models. The impact of the drug on tumor response to radiation therapy was also tested in a mouse model of human HNC.ResultsRadiation-induced tissue ulcerations were radiation-dosage and -time dependent. The lesions showed selective increases in PRR and pro-inflammatory cytokine gene expression levels. Once daily administration of GM-1111 (≥30 mg/kg, s.c.) significantly reduced the severity and the incidence of OM. The drug had little effect on PRRs but significantly inhibited downstream pro-inflammatory cytokine genes. GM-1111 did not interfere radiation therapy to induce HNC SCC-25 tumor regression. Instead, we observed significant drug-induced tumor regression.ConclusionsRadiation induces tissue damages. The increased expression levels of PRRs and their downstream pro-inflammatory cytokine genes in the damaged tissues suggest their important contribution to the pathogenesis of OM. Drug GM-1111 that targets these innate immune molecules may be a potential drug candidate as an intervention for OM.

Oral microbiota transplantation fights against head and neck radiotherapy-induced oral mucositis in mice

Oral mucositis is a common radiotherapy-induced complication among nasal, oral and laryngeal cancer (NOALC) patients. This complication leads to decreased quality of life and has few treatments. Here, fractionated radiation was performed to mimic radiotherapy for NOALCs in mouse models. Oral microbiota transplantation (OMT) mitigated oral mucositis, as judged by reconstructed epithelium and tongue papillae, fewer infiltrated leukocytes and more proliferative cells in the oral epithelium. The gut microbiota impacted oral mucositis progression, and OMT restructured oral and gut bacteria configurations and reprogrammed the gene expression profile of tongue tissues. In vivo silencing of glossal S100 calcium binding protein A9 debilitated the radioprotection of OMT. In light of clinical samples, we identified that patients with different alteration trends of Lactobacillaceae frequency presented different primary lesions and prognoses of NOALC following radiotherapy. Together, our findings provide new insights into the oral-gut microbiota axis and underpin the suggestion that OMT might be harnessed as a novel remedy to fight against oral mucositis in NOALC patients following radiotherapy in preclinical settings. Of note, oral microorganisms, such as Lactobacillaceae, might be employed as biomarkers to predict the prognosis of NOALC with radiotherapy.

Locally administered heparin-binding epidermal growth factor-like growth factor reduces radiation-induced oral mucositis in mice

Oral mucositis refers to lesions of the oral mucosa observed in patients with cancer being treated with radiation with or without chemotherapy, and can significantly affect quality of life. There is a large unmet medical need to prevent oral mucositis that can occur with radiation either alone or in combination with chemotherapy. We investigated the efficacy of locally administered heparin-binding epidermal growth factor-like growth factor (HB-EGF), a potent epithelial proliferation and migration stimulator of the oral mucosa as a potential therapy to prevent radiation induced oral mucositis. Using a single dose (20 Gy) of radiation to the oral cavity of female C57BL/6 J mice, we evaluated the efficacy of HB-EGF treatment (5 µl of 10 µg/ml) solution. The results show that HB-EGF delivered post radiation, significantly increased the area of epithelial thickness on the tongue (dorsal tongue (42,106 vs 53,493 µm2, p < 0.01), ventral tongue (30,793 vs 39,095 µm2, *p < 0.05)) compared to vehicle control, enhanced new epithelial cell division, and increased the quality and quantity of desmosomes in the oral mucosa measured in the tongue and buccal mucosa. This data provides the proof of concept that local administration of HB-EGF has the potential to be developed as a topical treatment to mitigate oral mucositis following radiation.

Cannabidiol on 5-FU-induced oral mucositis in mice.

The aim of this study was to evaluate the clinical, histological, hematological, and oxidative stress effects of cannabidiol (CBD) in mice with induced oral mucositis. We used 90 mice of the CF-1 strain in which oral mucositis was induced using a protocol with 5-fluorouracil (5-FU) chemotherapy. The animals were divided randomly into 10 study groups. Three groups were treated with different doses of CBD (3, 10, and 30mg/kg), while 2 were control groups (positive control: 5-FU+mechanical trauma+placebo; and negative control: mechanical trauma+placebo), and 2 experimental times were studied (4 and 7days). All treatments were by intraperitoneal administration. In the clinical evaluation, the groups treated with CBD showed less severity of oral lesions compared with the positive control at both experimental times. The intensity of the inflammatory response was also lower in the groups treated with this drug, but there was no statistically significant difference when compared with the positive control. With regard to erythrocyte, leukocyte, and platelet counts and anti-oxidant enzyme activity, the groups treated with CBD showed better results, but only some of these variables showed statistically significant differences. CBD seems to exert an anti-inflammatory and anti-oxidant activity favoring a faster resolution of oral mucositis in this animal model.

Topical Melatonin Niosome Gel for the Treatment of 5-FU-Induced Oral Mucositis in Mice.

Oral mucositis, one of the most common complications of 5-Fluorouracil (5-FU) treatment, leads to several problems, including pain, diarrhea and malnutrition, and reduces the quality of life and subsequent treatments. Melatonin, a neurohormone with anti-inflammatory and antioxidant activities, was encapsulated in niosomes and embedded in a mucoadhesive gel formulation as a Melatonin Niosome Gel (MNG) to perform oral mucositis treatment. This study aimed to investigate the effectiveness of MNG for the treatment of 5-FU-induced oral mucositis in mice. Oral mucositis was induced in ICR mice by 5-FU and randomly assigned to receive daily applications of the topical oral MNG, a fluocinolone acetonide gel, a blank niosome gel, or no treatment for 5 days in comparison with a normal group. Average body weights, food consumption, and behaviors of the mice as well as microscopic histopathology, Fourier-Transform Infrared Spectroscopy (FTIR) analysis, proinflammatory cytokine levels, and oxidative stress markers of the tongues were monitored and collected after sacrifice. In comparison to the normal group, the average body weights of the 5-FU-MNG mice did not deviate from that of the normal group, nor was there a significant difference in the time to sleep or licking (p>0.05 for both parameters). In addition, the mice treated with MNG and fluocinolone acetonide did not show significantly different histopathological, FTIR, interleukin-1β or malondialdehyde (MDA) results in the tongues used as the oral tissue samples. Topical MNG potentially inhibits inflammation and lipid oxidative stress in 5-FU-induced oral mucositis.

Glutaryl Melatonin Niosome Gel for Topical Oral Mucositis: Anti- Inflammatory and Anticandidiasis.

Glutaryl melatonin, which is synthesized from melatonin and is a pineal glandderived neurohormone with anti-inflammatory and anti-oxidant properties, was comparatively investigated for its potential use as a topical anti-inflammatory agent. Glutaryl melatonin, synthesized and screened for in vitro anti-candidiasis and in vitro and in vivo anti-inflammatory activities, was formulated as a niosome gel for topical oral evaluation in 5- fluorouracil-induced oral mucositis in mice. In vitro anti-fungal activity in Candida albicans, in vitro anti-inflammatory activity in Escherichia coli liposaccharide-induced RAW cells and in vivo anti-inflammatory activity using a croton oilinduced ear edema model in ICR mice were investigated. Mucositis in mice (n= 6/group, 10-week-old mice) was induced by intraperitoneal injections of 5-fluorouracil, and the mice were subjected to a topical oral application of niosome gel containing melatonin (2% w/w) or glutaryl melatonin (2% w/w) and were compared with mice subjected to blank, fluocinolone acetonide (0.5% w/w) and control conditions. Glutaryl melatonin, at a 14.2 mM concentration, showed the highest fungicidal effect on C. albicans using the broth dilution method, indicating a nonsignificant difference from 1 μM of nystatin (p = 0.05). Nitric oxide, interleukin-6 and tumor necrosis factors were analyzed by ELISA. Liposaccharide-induced RAW cells were significantly reduced by glutaryl melatonin (p < 0.01). Ear edema inhibition of glutaryl melatonin was significant 1 h after application compared with that of melatonin (p = 0.03). Food consumption and body weight of the 5-fluorouracil-treated mice were significantly lower than those of the normal mice before all treatments (p < 0.05). Differences in the amount of licking behavior, which were observed in the control group for 5 min, were noticeable in the 5- fluorouracil-treated mice but not in the mice treated with the glutaryl melatonin niosome gel. Glutaryl melatonin exhibited mild anti-candidiasis and anti-inflammatory properties. The incorporation of glutaryl melatonin in a niosome gel formulation, demonstrated the potential for topical oral applications to reduce oral discomfort caused by 5-fluorouracil treatment in mice.

Heparin treatment mitigates radiation-induced oral mucositis in mice by interplaying with repopulation processes

PurposeTo investigate the mechanistic background of the muco-protective effect of systemic heparin treatment on the development of radiation-induced oral mucositis in mice.Materials and methodsFractionated irradiation was given to the snouts of male C3H/Neu mice over 2 weeks (10 × 3 Gy), either alone or in combination with daily subcutaneous application of unfractionated or low molecular weight heparin (40 or 200 I.U./mouse, respectively). Over this course of 14 days, groups of mice (n = 3) were sacrificed every second day, their tongues excised and processed for histological analysis. The epithelial radiation response with and without heparin treatment was evaluated in terms of tissue morphology, proliferation and expression of cell contact molecules.ResultsSystemic treatment with heparins significantly reduced the cellular effects of irradiation to the oral epithelium. Heparin treated animals showed significantly higher total epithelial cell numbers and thickness throughout the study course. Bromodeoxyuridine (BrdU) incorporation analyses revealed that markedly more epithelial cells retained their proliferative capacity in the beginning of the first treatment week, but the proliferation of the mucosa was not stimulated during the rest of the study course. The expression of the adherens junction protein β‑catenin was slightly elevated in heparin treated animals, on day 2 the increase was statistically significant. The expression of e‑cadherin and occludin was mostly unaffected by the concomitant heparin treatment.ConclusionThe findings of this study indicate an interplay of additional heparin treatment with the repopulation processes, leading to an earlier onset of this adaptive radiation response in oral mucosa. Importantly, we could demonstrate that the protective potential of heparin did not rely on stimulation of normal tissue proliferation. Since both heparin preparations are already approved for clinical use, they are considered as promising candidates for future clinical studies.

Peroxisome proliferator activated receptor-gamma stimulation for prevention of 5-fluorouracil-induced oral mucositis in mice.

Oral mucositis is a side effect of treatment regimens containing 5-fluorouracil (5-FU). The purpose of this study was to present our evaluation to see if rosiglitazone (RGZ) protected normal tissues from chemotherapy-induced oral mucositis. C57BL/6J mice were treated with 5-FU for 5 days, with or without RGZ. Mice were euthanized after 5, 8, 11, or 15 days, and mucosal segments were collected. The RGZ did not affect the 5-FU-induced decrease in mouse body weight. The 5-FU caused loss of epithelial architecture, collagen fiber impairment, and inflammatory infiltration. The RGZ reduced leukocyte infiltration, preserved tissue structure, and dampened the 5-FU-induced expression of p53 and matrix metalloproteinase (Mmp)-2 after 5 days, and of Mmp-2 and interleukin (Il-1β after 15 days. The RGZ inhibited the 5-FU-induced increase of transforming growth factor-beta (TGF-β) and nuclear factor-kappa B (NF-κB) proteins and restored collagen protein levels. The RGZ had a protective effect on oral mucosa damaged by chemotherapy. These data encourage the further study of RGZ for the prevention of 5-FU-induced mucositis in patients with cancer.

Chemotherapy Induces Oral Mucositis in Mice Without Additional Noxious Stimuli

Oral mucositis (OM) is a serious side effect of cancer chemotherapy. The pathobiology of oral mucositis remains incompletely understood due to lack of appropriate models which recapitulate the human condition. Existing rodent models are intraperitoneal and require radiation, chemical or mechanical injury to the chemotherapy protocol to induce oral lesions. We aimed to develop an OM mouse model that is induced solely by chemotherapy and reproduces macroscopic, histopathologic and inflammatory characteristics of the human condition. Female C57BL/6 mice were given intravenous 5-Fluorouracil (5-FU) injections every 48 hours, for 2 weeks. A high daily dose of intraperitoneal administration was tested for comparison. Mice were monitored daily for weight loss. Epithelial histomorphometric analyses in tongue, esophageal and intestinal tissues were conducted coupled with assessment of apoptosis, cell proliferation, neutrophilic infiltration and the integrity of adherens junctions by immunohistochemistry. Neutropenia was assessed in peripheral blood and bone marrow. Tissues were analyzed for pro-inflammatory cytokines at the protein and mRNA levels. Daily intraperitoneal administration of 5-FU led to rapid weight loss and intestinal mucositis, but no oral inflammatory changes. Intravenous administration triggered atrophy of the oral and esophageal epithelium accompanied by reduction in cell proliferation and increased apoptosis. Coincidental with these changes were up-regulation of NF-κB, TNFα, IL-1β, GM-CSF, IL-6 and KC. Despite neutropenia, increased oral neutrophilic infiltration and reduced E-cadherin was observed in oroesophageal mucosae. We developed a novel experimental tool for future mechanistic studies on the pathogenesis of chemotherapy-induced OM.

Nocifensive Behaviors in Mice with Radiation-Induced Oral Mucositis.

Oral mucositis can result in significant dysphagia, and is the most common dose-limiting acute toxicity in head and neck cancer patients receiving chemoradiotherapy. There is a critical need to determine the cellular and molecular mechanisms that underlie radiotherapy-associated discomfort in patients with mucositis. The objective was to induce oral mucositis in mice, using a clinical linear accelerator, and to quantify resultant discomfort, and characterize peripheral sensitization. A clinical linear accelerator was used to deliver ionizing radiation to the oral cavity of mice. Mucositis severity scoring, and various behavioral assays were performed to quantify bouts of orofacial wiping and scratching, bite force, gnawing behavior and burrowing activity. Calcium imaging was performed on neurons of the trigeminal ganglia. Glossitis was induced with a single fraction of at least 27 Gy. Body weight decreased and subsequently returned to baseline, in concert with development and resolution of mucositis, which was worst at day 10 and 11 postirradiation, however was resolved within another 10 days. Neither bite force, nor gnawing behavior were measurably affected. However, burrowing activity was decreased, and both facial wiping and scratching were increased while mice had visible mucositis lesions. Sensory nerves of irradiated mice were more responsive to histamine, tumor necrosis factor alpha and capsaicin. Radiation-induced glossitis is associated with hyper-reactivity of sensory neurons in the trigeminal ganglia of mice, and is accompanied by several behaviors indicative of both itch and pain. These data validate an appropriate model for cancer treatment related discomfort in humans.

Protective effect of yeoldahanso-tang on radiation-induced oral mucositis in mice

Radiation-induced oral mucositis is probably the most common toxicity for head and neck cancer patients. This adverse effect potentially leads to various lesions such as erythema, ulcerations, pain, opportunistic infections, and weight loss. Although there are many experimental studies and clinical trials related to novel therapies for radiation-induced oral mucositis, we here evaluate the protective effect of orally administrated Yeoldahanso-tang (YDHS) on radiation-induced oral mucosal damage in a mouse model. YDHS is a traditional Korean herbal formula, containing 7 herbs: Pueraria thunbergiana Benth., Angelica tenuissima Nakai, Platycodon grandiflorum (Jacq.) A. DC., Raphanus sativus var., Angelica dahurica Benth. et Hooker f., Cimicifuga heracleifolia Kom., and Scutellaria baicalensis Georgi. Oral mucosal damage was induced by irradiation (17 Gy) throughout the head and neck area in male BALB/c mice. YDHS (400 or 800 mg/kg/day for consecutive 12 days) was administered orally, and the protective effect was determined by histological evaluation of the oral mucosa. We found that irradiation highly increased COX-2 expression in salivary glands and its expression was suppressed by YDHS. Histologically, the irradiated mice exhibited the epithelial thickness from the basement membrane to the stratum granulosum significantly decreased as compared to the vehicle group. YDHS-treated mice showed significantly recovered epithelial cell layer thickness compared to irradiated group. Similarly, YDHS-treated group also showed the expression of Ki-67, cell proliferation maker, in the basal layer compared to the irradiated group in both dorsal and ventral surface. From these results, we suggest that YDHS is a promising candidate for preventing or treating radiation-induced oral mucositis during radiation therapy.

Evaluation of edaravone against radiation-induced oral mucositis in mice

Oral mucositis induced by radiotherapy for cancers of the head and neck reduce the quality of life of patients. However, effective therapeutic agents are lacking. Symptomatic treatment involves local anesthesia and analgesia. We focused on the antioxidant effects of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one; Radicut®). Oral mucositis was induced on the tongue tips of mice using a single dose of X-rays (20 Gy). To evaluate the protective effect of edaravone (30 and 300 mg/kg), administration was carried out 30 min before irradiation. Survival, oral mucositis score, myeloperoxidase activity, and levels of 2-Thiobarbituric acid reactive substances were measured, and all were improved compared with those of control mice. A significant difference was not found in terms of survival due to edaravone. Histopathologic findings also highlighted the beneficial features of edaravone. Edaravone reduced the production of reactive oxygen species. These findings suggest that the protective effect of edaravone against radiation-induced oral mucositis is through an antioxidant effect.

Optimum topical delivery of adrenergic agonists to oral mucosa vasculature.

Identify an orotopical vehicle to deliver an α-adrenergic vasoconstrictor to submucosal vasculature that is readily palatable to cancer/bone marrow transplant patients that suppresses chemo-radiotherapy-associated oral mucositis. A [(3)H] norepinephrine ligand binding assay was developed to quantify receptor binding in hamster oral mucosa. Vehicle components (alcohols, polyols, cellulose, PVP) were tested versus [(3)H] norepinephrine binding. Vehicle refinement was also done to mask phenylephrine bitter taste and achieve human subject acceptance. The optimized vehicle was tested with α-adrenergic active agents to suppress radiation-induced oral mucositis in mice. The ligand binding assay quantified dose- and time-dependent, saturable binding of [(3)H] norepinephrine. An ethanol:glycerol:propylene glycol:water (6:6:8:80) vehicle provided the best delivery and binding. Further vehicle modification (flavoring and sucralose) yielded a vehicle with excellent taste scores in humans. Addition of phenylephrine, norepinephrine or epinephrine to the optimized vehicle and painting into mouse mouths 20 min before 19 Gy irradiation conferred significant suppression of the weight loss (P < 0.001) observed in mice who received oral vehicle. We identified a highly efficient vehicle for the topical delivery of phenylephrine to the oral mucosa of both hamster and human subjects. This will enable its testing to suppress oral mucositis in an upcoming human clinical trial.

Preventive and therapeutic effects of Smad7 on radiation-induced oral mucositis

We report that K5.Smad7 mice, which express Smad7 transgene by a keratin-5 promoter, were resistant to radiation-induced oral mucositis, a painful oral ulceration. In addition to NF-κB activation known to contribute to oral mucositis, we found activated TGF-β signaling in oral mucositis. Smad7 dampened both pathways to attenuate inflammation, growth inhibition and apoptosis. Additionally, Smad7 promoted oral epithelial migration to close the wound. Further analyses revealed that TGF-β signaling Smads and their co-repressor CtBP1 transcriptionally repressed Rac1, and Smad7 abrogated this repression. Knocking down Rac1 in mouse keratinocytes abrogated Smad7-induced migration. Topically applying Smad7 protein with a cell permeable Tat-tag (Tat-Smad7) to oral mucosa showed preventive and therapeutic effects on radiation-induced oral mucositis in mice. Thus, we have identified novel molecular mechanisms involved in oral mucositis pathogenesis and our data suggest an alternative therapeutic strategy to block multiple pathological processes of oral mucositis.

Low Level Laser Therapy in 5-FU induced oral mucositis in mice

Low Level Laser Therapy in 5-FU induced oral mucositis in mice