Effects of propolis on lingual mucosa response of hamsters submitted to experimental carcinogenesis

Abstract

To assess the tissue reaction of the lingual mucosa in hamsters submitted to daily, alternating, topical applications of 9,10-dimethyl-1,2-benzanthracene (DMBA) and a commercial brand of an ethanol propolis extract (EPE). A total of 60 hamsters were divided into three groups with two experimental periods (13 and 20 weeks). The lateral edge of the tongue was submitted to daily, alternating, topical applications of 0.5% DMBA and 30% EPE (EPE group, n=20), 0.5% of DMBA and aqueous propolis extract (APE group, n=20) and 0.5% of DMBA and saline solution (DMBA group, n=20). The occurrence of clinical and histological alterations was analyzed, along with the measurement of the area and volume of the clinical alterations, the determination of structural and cytological alterations of the squamous epithelial tissue with atypias and the measurement of the histological area of squamous cell carcinomas. There were no significant differences among groups regarding any of the variables analyzed in the two evaluation periods. At week 13, a single squamous cell carcinoma occurred in the EPE group. At week 20, the greatest occurrence of squamous cell carcinoma was also in the EPE group. The mechanism of EPE (30% alcohol content) affecting the onset of tissue reaction and the promotion of carcinogenesis has not been clarified yet.