Evaluation of topical external medicine for 5-fluorouracil-induced oral mucositis in hamsters

Development of mucoadhesive films with high polaprezinc content for oral mucositis: A study on formulation and near-infrared spectroscopy-based quality control

Polaprezinc (PLZ) has drawn attention to its potential to prevent oral mucositis caused by chemotherapy and radiotherapy. PLZ-containing lozenges have been developed in previous reports; however, for patients with mucositis, taking them may be challenging because of pain. Therefore, this study aimed to develop a mucoadhesive film containing the same amount (18.75 mg) of PLZ as a lozenge as a new dosage form to replace lozenges and evaluate its characteristics. First, various films were created using solvent casting to screen polymers with high PLZ content. Thus, hydroxypropyl cellulose (HPC) was selected; however, film curvature and reduced flexibility necessitated formulation optimization. The optimized films exhibited excellent content uniformity, stability, and mucoadhesive properties, with no significant changes in the drug content after storage. Furthermore, the possibility of using portable near-infrared spectroscopy (Micro NIR™) for the quality control of PLZ films was investigated. Multivariate analysis revealed that the Micro NIR calibration model predicted drug concentrations comparable to those measured by high-performance liquid chromatography. These results suggest that a mucoadhesive film with high PLZ content has been developed and that efficient quality control is possible using Micro NIR™.

A randomised trial of topical polaprezinc to prevent oral mucositis in patients undergoing haematopoietic stem cell transplantation (ToPaZ study)

PURPOSE

Oral mucositis (OM) is a common complication in haematopoietic stem cell transplantation (HSCT). Polaprezinc, an anti-ulcer drug, has been shown to be effective to prevent OM in several studies when administered topically and systemically. This study aimed to evaluate the effectiveness of topical polaprezinc in patients undergoing HSCT.

METHODS

This was an open-label randomised clinical trial comparing polaprezinc and sodium bicarbonate mouthwashes for the prevention of severe OM in HSCT patients. Adult patients who received conditioning regimens at moderate to high risk of developing OM were included. The primary endpoint was the incidence of severe (WHO grades 3-4) OM. The secondary endpoints included duration of grades 3-4 OM, incidence and duration of grades 2-4 OM, patient-reported pain and functional limitations.

RESULTS

In total, 108 patients (55 test arm and 53 control arm) were randomised. There was no difference in the incidence of grades 3 to 4 OM (35% test arm versus 36% control arm). The secondary endpoints were not significantly different. In both arms, patients reported more throat pain compared to mouth pain.

CONCLUSIONS

Topical polaprezinc had no effect in the prevention of OM in HSCT patients. Further research is required to evaluate the effects of systemic polaprezinc. The OM assessment tool needs to be reviewed as throat mucositis was a main issue in this study.

TRIAL REGISTRATION

ACTRN12320001188921 (Date Registered: 10th November 2020).

Effectiveness of zinc supplementation on the incidence of oral mucositis during chemotherapy and radiation: A meta‑analysis

Oral mucositis (OM) is a commonly observed and debilitating side effect of chemotherapy and radiation therapy in patients with cancer, especially head and neck cancer. Although there is no proven therapy for the prevention and treatment of OM, zinc supplementation effectively decreases the incidence of OM. This paper provides a current and comprehensive meta-analysis of the efficacy of zinc compared with placebo/control in OM. A systematic literature review was conducted using MEDLINE and Central databases for randomized control trials (RCTs) comparing zinc supplementation (oral or rinse) with placebo/control in patients with various types of cancer undergoing chemotherapy, radiation therapy or combined chemo-radiation. The outcome was OM incidence, independent of the severity. A random-effects model was used to calculate the pooled risk ratio and subgroup analyses were performed. A total of 12 RCTs were included, containing information from 783 patients. A decrease in OM incidence was observed overall when all cancer therapies were considered. However, subgroup analyses showed that zinc did not significantly decrease the incidence of OM when studies were stratified by cancer therapy or scale/criteria used to assess OM. The results of the meta-analysis support the use of zinc supplementation in decreasing OM incidence in patients with cancer receiving chemotherapy or radiation therapy. However, the high heterogeneity between studies and the small number of studies are limitations of the meta-analysis.

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.

Analgesic Mechanisms of Steroid Ointment against Oral Ulcerative Mucositis in a Rat Model

Despite the long history of use of steroid ointments for oral mucositis, the analgesic mechanism has not been fully elucidated. In this study, we examined the effects of triamcinolone acetonide (Tmc) on oral ulcerative mucositis-induced pain in conscious rats by our proprietary assay system. Based on evaluations of the physical properties and retention periods in the oral mucosa of human volunteers and rats, we selected TRAFUL^® ointment as a long-lasting base. In oral ulcerative mucositis model rats, TRAFUL^® with Tmc suppressed cyclooxygenase-dependent inflammatory responses with upregulations of glucocorticoid receptor-induced anti-inflammatory genes and inhibited spontaneous nociceptive behavior. When an ointment with a shorter residual period was used, the effects of Tmc were not elicited or were induced to a lesser extent. Importantly, TRAFUL^® with Tmc also improved oral ulcerative mucositis-induced mechanical allodynia, which has been reported to be independent of cyclooxygenase. Ca²⁺ imaging in dissociated trigeminal ganglion neurons showed that long-term preincubation with Tmc inhibited the hypertonic stimulation-induced Ca²⁺ response. These results suggest that the representative steroid Tmc suppresses oral ulcerative mucositis-induced pain by general anti-inflammatory actions and inhibits mechanical sensitivity in peripheral nerves. For drug delivery, long-lasting ointments such as TRAFUL^® are needed to sufficiently induce the therapeutic effects.

Turmeric based oral rinse "HTOR-091516" ameliorates experimental oral mucositis

Background:

Prevalence and incidence of oral mucositis (OM) are rigorously increasing and there is no effective treatment. The herbal formulation “HTOR-091516” containing Curcuma longa, Triphala and honey were evaluated for the treatment of OM.

Aim:

The aim of this study was to evaluate the safety and efficacy of HTOR-091516, employing cellular model, human gingival fibroblasts-1 (HGF-1), and 5-fluorouracil (5-FU)-induced mucositis model in rats.

Materials and Methods:

The cell viability was assessed using 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay and the inhibitory effect of HTOR-091516 on tumor necrosis factor-alpha (TNF-α) was evaluated using TNF-α bioassay in lipopolysaccharides-induced HGF-1. 5-FU and glacial acetic acid were used to induce OM in rats. Animals were divided into two groups, group 1 served as mucositis control and group 2 was treated with HTOR-091516 at the dose of 200 μl and TNF-α was estimated in plasma samples.

Results:

The in vitro safety of HTOR-091516 was evaluated in reconstructed human oral epidermis and was found to be nontoxic and exhibited concentration-dependent TNF-α inhibition in HGF-1. The treatment with HTOR-091516 reduced mucositis scores and mortality rate and also decreased the plasma TNF-α level.

Conclusion:

The present data indicate that HTOR-091516 is effective in the treatment of OM.

Wound Healing Promoting Activity of Tonsil-Derived Stem Cells on 5-Fluorouracil-Induced Oral Mucositis Model

BACKGROUND

We first determined the efficacy of lesional injection of tonsil-derived MSCs (mesenchymal stem cells) for the treatment of 5-fluorouracil induced oral mucositis.

METHODS

Oral mucositis was induced in hamsters by administration of 5-fluorouracil (day 0, 2, 4) followed by mechanical trauma (day 1, 2, 4). The experimental groups included MT (mechanical trauma only), 5-FU + MT (mechanical trauma with 5-fluorouracil administration), TMSC (mechanical trauma with 5-fluorouracil administration, tonsil-derived mesenchymal stem cells injection), DEXA (mechanical trauma with 5-fluorouracil administration, dexamethasone injection), and saline (mechanical trauma with 5-fluorouracil administration, saline injection).

RESULTS

On day 10, gross and histologic analyses showed that nearly complete healing and epithelialization of the cheek mucosa of the TMSC group, whereas the other groups showed definite ulcerative lesions. Compared with the MT and DEXA groups, CD31 expression was greater in the TMSC group on days 10 and 14. Tendency towards a decrease in MMP2 expression with the time in the TMSC group was observed. In addition, the TMSC group showed higher expression of TGF-β, and NOX4 on day 10 compared with the other groups. Scratch assay demonstrated that the conditioned media harvested from tonsil-derived MSCs significantly increased migratory efficacy of NIH3T3 cells. Transwell assay showed that the preferential migration of tonsil-derived MSCs to the wound area.

CONCLUSION

Intralesional administration of tonsil-derived MSCs may accelerate wound healing of 5-fluorouracil induced oral mucositis by upregulating neovascularization and effective wound contraction. In addition, tonsil-derived MSCs might contribute to oral ulcer regeneration via the stimulation of fibroblast proliferation and migration.

Utility of polaprezinc in reducing toxicities during radiotherapy: a literature review

Chemoradiotherapy is important for treating malignancies. However, radiation-induced toxicities develop as chemoradiotherapy-related complications. Various agents reduce or prevent toxicities, but there are no standard treatments. Polaprezinc (PZ), a chelating compound used for gastric ulcers, has antioxidant and free radical scavenging effects. Although few studies have evaluated PZ and radiation-induced normal tissue damage, several clinical studies have shown the efficacy of PZ for oral mucositis, esophagitis, proctitis and taste alterations during and after radiotherapy. Moreover, preclinical data support the clinical data, indicating good potential of testing PZ in future trials. However, as there are only few well-documented review articles on PZ use in cancer treatment, we conducted this literature review. PZ reduced several radiation-induced toxicities and improved the quality of life.

Probiotic therapy reduces inflammation and improves intestinal morphology in rats with induced oral mucositis

The aim of the present study was to evaluate the effect of systemic administration of probiotics (PROB) on the progression of experimentally induced oral and intestinal mucositis in rats immunosuppressed by chemotherapy (5-fluorouracil: 5-FU). Twenty-four rats were divided into the following groups (n=6): GC (control), GPROB, G5FU and G5-FU/PROB. Groups GPROB and G5-FU/PROB received 1 g of probiotic incorporated into each 100 g of feed (Bacillus subtilis, Bifidobacterium bifidum, Enterococcus faecium and Lactobacilllus acidophilus), beginning 30 days before oral mucositis induction. Groups G5FU and G5-FU/PROB received 60 mg/kg of 5-FU on days 0 and 2. The left oral mucosa of each animal was irritated by mechanical trauma (days 1 and 2). On days 3 and 7, three animals from each group were sacrificed, and their oral mucosa and small intestine were biopsied and processed for histopathological analysis. Groups G5-FU and G5-FU/PROB showed ulcerated oral lesions at day 3, with progression in group G5-FU and regression in group G5-FU/PROB at day 7. Histologically, less severe signs of inflammation in the oral mucosa were observed in group G5-FU/PROB than in group G5-FU. Regarding the intestine, villus-related defects of lesser magnitude were observed in group G5-FU/PROB, compared with group G5-FU. Group GPROB showed greater villus height than group GC. It can be concluded that probiotic supplementation reduced oral and intestinal inflammation in immunosuppressed rats with experimentally induced mucositis, and may protect the intestine from changes induced by chemotherapy, thus contributing to overall health.

WITHDRAWN: Survivin, Caspase-3 and Caspase-9-activated proteins kinases in apoptosis

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Evaluation of current and upcoming therapies in oral mucositis prevention

Cancer chemotherapy has evolved from a few therapeutic agents in three drug classes to more than 50 drugs in over ten drug classes. With generally cytotoxic mechanisms of action, there is continued research interest in preventing and managing adverse events of chemotherapy. Although treatment-induced symptom management has made significant progress, most therapies lead to intolerable reactions that result in a dose reduction or discontinuation of therapy. Mucositis is a common adverse event that can occur after administration of systemic chemotherapy and/or radiation therapy leading to inflammatory lesions anywhere from the oral cavity to the GI tract. Although pathophysiologically similar, gastrointestinal mucositis and oral mucositis (OM) differ in terms of symptom presentation and offending therapies. The focus of the article will be on OM; gastrointestinal mucositis will be mentioned when therapy efficacy is relevant to OM. OM prophylaxis has been a subject of interest for at least the past 30 years, yet progress has been limited due to a lack of understanding of the condition. With the recent introduction of palifermin (Kepivance™), novel therapies continue to be developed that may significantly reduce the incidence, duration and/or severity of OM. In addition, outcomes including an improvement in patient quality of life, increasing treatment dose intensity or reducing healthcare costs may result from successful management of OM prophylaxis. This article will review currently available OM prophylactic therapies. Agents in preclinical or clinical development and natural supplements will also be discussed.

Polaprezinc prevents oral mucositis associated with radiochemotherapy in patients with head and neck cancer

Oral mucositis is frequent but serious adverse event associated with radiotherapy or radiochemotherapy in head and neck cancer severely impairs health-related quality of life, leading to poor prognosis due to discontinuation of the therapy. Although a number of compounds have been tested for prophylaxis of oral mucositis, few of them are satisfactory. We investigated the effect of polaprezinc (zinc L-carnosine), a gastric mucosal protective drug, on radiochemotherapy-induced oral mucositis, pain, xerostomia and taste disturbance in patients with head and neck cancer. Patients were randomly assigned to receive polaprezinc (n = 16) or azulene oral rinse as the control (n = 15). The incidence rates of mucositis, pain, xerostomia and taste disturbance were all markedly lower in polaprezinc group than in control. Moreover, the use of analgesics was significantly (p = 0.003) less frequent and the amount of food intake was significantly (p = 0.002) higher in polaprezinc group than in control. On the other hand, tumor response rate in patients with neoadjuvant radiochemotherapy was not significantly affected by polaprezinc, in which the response rate (complete plus partial response) was 88% for polaprezinc and 92% for control (p = 1.000). Therefore, it is highly assumable that polaprezinc is potentially useful for prevention of oral mucositis and improvement of quality of life without reducing the tumor response.

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.

Biochemical evaluation of the therapeutic effectiveness of honey in oral mucosal ulcers

The aim of this study was to describe and quantify the therapeutic value of honey in oral mucosal ulcers healing in comparison with Glyceroloxytriester (TGO). We also aimed to biochemically evaluate the healing effects of honey which had been collected from the Blacksea region flora on mucosal ulcers resulting in material loss.Thirty wistar rats (240+/-30 g) were enrolled in this study. Excisional wounds were performed in all rats for animal oral mucosal ulcer model. They were randomly allocated to three groups: group 1 was treated with Apitherapeutic agent or honey (0,1 ml, 2x1), group 2 was treated with TGO (0,1ml, 2x1) locally, Group 3 served as the control group.Following the surgical procedure on day 7, biopsy specimens were taken from right buccal mucosa and on day 14 biopsy specimens were taken from left bucal mucosa in all rats. Afterwards, hydroxy pyroline levels were measured. Data were analyzed statistically.There was no statistically significant difference between Group 1 and 2, and also between Group 2 and 3, but there was statistically significant difference between Group 1 and 3 on day 7. There was no statistically significant difference between Group 1, 2 and 3 on day 14.

Protective effects of amifostine and cyclooxygenase-1 inhibitor against normal human epidermal keratinocyte toxicity induced by methotrexate and 5-fluorouracil

Our study aimed to find more effective protective agents against mucosa toxicity induced by methotrexate and 5-fluorouracil. We focused on the relationship between oral mucositis and keratinocyte injury and examined methotrexate and 5-fluorouracil-induced cytotoxicity in normal human epidermal keratinocyte cell lines. Cell viability and superoxide radical activity were measured based on converting WST-1 (4-[3-(4-indophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzen disulfonate) to a water-soluble formazan dye. DNA synthesis by 5-bromo-2'-deoxyuridine incorporation was measured as an indirect parameter of cell proliferation. Allopurinol and amifostine were used as the radical scavengers. l-glutamine was used as a mucosa-protective agent. A cyclooxygenase inhibitor interrupting the production of hydroxyl radicals in the arachidonic acid cascade was also examined. 5-fluorouracil and methotrexate caused cytotoxicity due to the activation of intracellular superoxide radicals specifically on normal human epidermal keratinocytes. From the electron spin resonance study, it was found that allopurinol was a superoxide radical scavenger, while amifostine was hydroxyl radical scavenger. Allopurinol showed no effect on the cytotoxicity due to 5-fluorouracil and methotrexate. The cell injury induced by methotrexate was restored by amifostine. However, the cell injury induced by 5-fluorouracil was markedly recovered by a selective cyclooxygenase-1 inhibitor compared to amifostine. It was suggested that amifostine and cyclooxygenase-1 inhibitor could be useful protective agents against methotrexate and 5-fluorouracil chemotherapeutic toxicity. Additionally, this in vitro cell injury model using normal human epidermal keratinocytes may be useful for understanding the pathophysiology of oral mucositis induced by chemotherapeutic agents.

The renal effects of alginates isolated from brown seaweed Sargassum vulgare

Alginates isolated from Sargassum vulgare, present a strong antitumor activity, associated with kidney reversible damage, as analysed by histopathology of treated animals. In the present study, the renal alteration mechanisms of S. vulgare alginates were investigated using the isolated perfused rat kidney and the isolated perfused rat mesenteric blood vessel methods. The results showed that the effects of Sargassum vulgare low viscosity (SVLV) alginate were more potent than those of Sargassum vulgare high viscosity (SVHV) alginate in the isolated rat kidney. The SVLV alginate caused considerable changes in renal physiology, as shown by an increase in parameters such as perfusion pressure, renal vascular resistance, glomerular filtration rate, urinary flow and sodium, potassium and chloride excretion and by reduction of chloride tubular transport. The effects of SVHV were weaker than those of SVLV. The effects of SVLV on kidney could be related to direct vascular action as demonstrated with SVLV alginate on mesenteric blood vessels. In conclusion, the Sargassum vulgare alginate altered the renal function parameters evaluated. S. vulgare low viscosity alginate renal effects were more potent than S. vulgare high viscosity alginate. It is suggested that physicochemical differences between SVHV and SVLV could explain the differences found in the results.

Intestinal mucositis: mechanisms and management

PURPOSE OF REVIEW

To describe the advances in the rapidly evolving field of intestinal (or alimentary) mucositis during the past year.

RECENT FINDINGS

Major advances have been made in both the clinical and preclinical setting, with the publication of a suite of articles regarding the pathobiology and management of mucositis, as well as several articles on important basic research in the area. The mechanism of mucositis development is now understood to be much more complex than previously thought, with an interplay of host and drug factors leading to overt damage, and variation in manifestation of that damage depending on the specific region of the gut. The MASCC/ISOO management guidelines for mucositis have been updated: a recommendation for the use of palifermin in the hematology transplant setting has been added, and a couple of previous recommendations have been revoked. This marks an important milestone in mucositis, as it is the first time a drug has been available that substantially reduces the occurrence and severity of mucositis.

SUMMARY

There is still much to be done to abolish the severe toxicity of chemotherapy and radiotherapy; however, progress is accelerating, and new targeted drugs are becoming available.

Inhibition of human gastric carcinoma cell growth by treatment of N(3)-o-toluyl-fluorouracil as a precursor of 5-fluorouracil

N(3)-o-toluyl-fluorouracil (TFU), the pro-drug of 5-fluorouracil (5-FU), is the metabolite of N(1)-acetyl-N(3)-o-toluyl-fluorouracil (atofluding). We aimed to evaluate the efficacy of TFU as a precursor of 5-FU on the growth inhibition of human gastric carcinoma cell lines SGC-7901 and MKN-45. Growth of SGC-7901 and MKN-45 cells was remarkably suppressed by treatment with TFU in the presence of liver microsomal enzymes in vitro, suggesting that TFU may be converted to 5-FU by the enzymes. Similar treatment of TFU induced apoptosis of the cells, which was deduced from typical apoptotic features such as morphology, the formation of characteristic ladder pattern of DNA migration and the accumulation of sub-G1 phase. Cancer cells xenografts in nude mice were employed to evaluate the efficacy of TFU in vivo. Growth of human gastric carcinoma cells was significantly delayed by oral administration of TFU with low side effects. Apoptosis in xenografts was also observed by means of TUNEL staining method. These results suggest that the treatment of TFU in the presence of liver microsomal enzymes and the oral administration of TFU in mice induced anti-proliferation and apoptosis in gastric carcinoma cells. This suggests that TFU may be a promising pro-drug of 5-FU for cancer treatments.

The role of pro-inflammatory cytokines in cancer treatment-induced alimentary tract mucositis: pathobiology, animal models and cytotoxic drugs

Alimentary tract (AT) mucositis can be a major problem for patients undergoing cancer treatment. It has significant clinical and economic consequences and is a major factor that can compromise the provision of optimal treatment for patients. The pathobiology of AT mucositis is complex and the exact mechanisms that underlie its development still need to be fully elucidated. Current opinion considers that there is a prominent interplay between all of the compartments of the mucosa involving, at a molecular level, the activation of transcription factors, particularly nuclear factor-kappaB, and the subsequent upregulation of pro-inflammatory cytokines and inflammatory mediators. The purpose of this review is to examine the literature relating to what is currently known about the pathobiology of AT mucositis, particularly with respect to the involvement of pro-inflammatory cytokines, as well as currently used animal models and the role of specific cytotoxic chemotherapy agents in the development of AT mucositis.