Effect of Systemic Dexamethasone Premedication on Short-term Experimentally Induced Oral Mucositis in Hamsters

Statement of Problem: Oral Mucositis (OM) is a frequent and well-known side effect of cancer chemotherapy as well as head and neck radiation therapy. Considering the proposed critical role of pro-inflammatory cytokines and an important cellular transcription factor (Nuclear Factor-kappaB) in pathogenesis of OM, an animal study was planned to evaluate the possible effects from powerful inhibition of the above-mentioned factors on OM. Evaluation of the effects of systemic dexamethasone (DEX) premedication on the course and severity of a short-term chemotherapy-induced OM in an animal model. In this trial, 75 male adult golden hamsters were recruited by random division to three groups as following: Group A: Received neither chemotherapy nor DEX premedication. Group B: Received chemotherapy and also normal saline as premedication. Group C: Received chemotherapy and also DEX as premedication in specified dosages for three sub-groups, each with 15 animals.Chemotherapy was administered by once daily injections of 5-Fluorouracil on the days 1 and 2 of the experiment. Premedications implied either as normal saline or DEX, were administered as once daily injections at the same time of days 1 to 9; those of the days 1 and 2 were followed one hour later by 5-FU injections. On the fourth day of the experiment, the cheek pouch mucosa of all animals were irritated by scratches of sterile needle tip to potentiate OM. On the days 6, 9 and 16, the cheek pouches were examined clinically and histopathologically for determination of definite macroscopic and microscopic scores in a blind fashion. Moreover, on the day 9, blood sampling for culture as well as histopathologic analysis for oral candidiasis were carried out respectively on randomized subsets of 2 and 5 animals per each group. The data were analyzed by Kruskal-Wallis test. Comparison of macroscopic as well as microscopic scores among different groups, showed prominent protective role from DEX premedication at high and moderate dosages, seen clinically as less severe forms of OM. The most important negative outcome from DEX premedication was mortality in a number of animals, with the most occurring in the high-dosage subgroup. It seems that among the three dosages of DEX premedication in this trial, the moderate dose (0.1 mg/kg) showed good results, both in terms of less mortality and also remarkable effect on reducing the severity of OM.