Effects of dose-dependent response to gamma radiation on circumvallate papilla by expression of caspase-3 in vivo

BACKGROUND: Radiotherapy is one of the most significant treatment modality of head and neck cancers. However, it has various hazards on the normal tissues in the radiation field. One of these affected tissues is the lingual mucosa with their papillae such as circumvallate papilla. The effects of radiation on the lingual specialized mucosa may be represented by radiation-induced mucositis and taste alteration including partial or complete loss of taste. OBJECTIVES: The aim of the study was to evaluate the dose-dependent response of circumvallate papillae to gamma radiation by immunohistochemical expression of caspase-3. MATERIAL AND METHODS: Twenty-four adult male albino rats were divided into 3 equal groups irradiated at 2.0, 4.0 and 6.0 Gy whole-body gamma radiation doses. Six non-irradiated rats were used as the control group. The radiation effects on circumvallate papillae were evaluated three days after irradiation via histomorphometric investigation of the papillary size and taste buds’ distortion in addition to an immunohistochemical assessment of the apoptotic activity using Caspase-3 marker. RESULTS: Dose-related changes were observed in the circumvallate papillae size and morphology and taste buds affection. The changes were obviously detected in rats irradiated at 4 Gy and 6 Gy doses. The detection of caspase-3 marker was evident in a dose-dependent manner in all the irradiated groups, more noticeably in the taste bud cells. CONCLUSIONS: It could be concluded that circumvallate papillae are adversely affected in a dose-dependent manner by gamma radiation particularly in 4 Gy and 6 Gy doses.