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.