Introduction: Radiotherapy is one of the common modalities in management of head and neck cancers. However, many injurious effects were reported on unavoidable oral tissues in the radiation field including the tongue and its heterogeneous internal structure. It is important to define the optimum dose of radiation with minimal hazards on the healthy tissues along with classification of the tissues according to their radio-sensitivity.
Purpose: To evaluate histomorphometrically and immunohistochemically the dose dependent response of lingual internal structures of rats exposed to gamma radiation.
Materials & Methods: Twenty-two adult male albino rats were divided into 3 groups: control group (6 rats), R1 group (8 rats) irradiated by 2.0 Gy whole-body gamma dose, and R2 group (8 rats) irradiated by 6.0 Gy. The effects on lingual internal structures were investigated after 3 days by histomorphometric and immunohistochemical staining for Caspase-3 using light microscopy.
Results: There were a dose related changes in the minor salivary glands with more changes in serous glands. Mild changes were observed in muscles only at 6 Gy dose. The expression percentage of caspase-3 protein was significantly increased in a dose dependent manner in both of the irradiated groups when compared with control group P0.05. Conclusion: Gamma radiation especially 6 Gy dose adversely affects the internal structures of the tongue with the most affected are serous acini and the least are the muscle cells.