单次大剂量X射线照射建立小鼠放射性口腔黏膜炎模型的实验研究

Establishment of radiation‐induced oral mucositis mouse model by single high‐dose X‐ray irradiation

目的建立单次大剂量X射线照射的小鼠放射性口腔黏膜炎模型。方法采用X射线单次照射小鼠头颈部的造模方式,将SPF级C57BL/6J小鼠55只,随机分为正常对照组,15、16、17和18 Gy照射组,每组11只,其中8只用于观察照后30 d存活和体质量变化,另外3只于照后9 d活杀,取舌组织进行甲苯胺蓝染色、HE染色和Ki67免疫组化标记,根据舌黏膜损伤程度确定最佳照射剂量。结果 15和16 Gy照射组小鼠30 d存活率分别为87.5%和12.5%,17、18 Gy照射组小鼠在11 d内全部死亡,照后9 d为最佳取材时间。15~18 Gy照射组小鼠口腔黏膜甲苯胺蓝染色均可见阳性着色,HE染色和Ki67免疫组化结果提示经X射线一次性头颈部照射剂量>17 Gy,能显著减少小鼠舌尖和舌背的上皮厚度以及上皮增殖细胞数量。结论 C57小鼠经17 Gy一次性头颈部照射,可用于放射性口腔黏膜炎模型的相关研究。

Objective To establish a single high⁃dose X⁃ray irradiated mouse model of radiation⁃induced oral mucosi⁃tis.Methods The heads and necks of mice were irradiated by single high⁃dose X⁃ray.Fifty⁃five SPF grade C57BL/6J mice were randomly divided into the normal control group,15 Gy,16 Gy,17 Gy and 18 Gy irradiation groups.There were 11 mice in each group,8 of which were used to observe the survival and body mass changes 30 days after irradiation while the other 3 were sacrificed 9 days after irradiation for histopathological observation of tongues.The best irradiation dose was de⁃termined according to the injury degree of tongue mucosa.Results The survival rate of mice in 15 Gy and 16 Gy groups was 87.5%and 12.5%,respectively.All the mice in 17 Gy and 18 Gy groups died within 11 days,and the best time for sampling was 9 days after irradiation.Toluidine blue staining was found in the oral mucosa of mice in 15-18 Gy groups.The results of HE staining and Ki67 immunohistochemistry suggested that the thickness of the epithelium and the number of proliferative cells in the tip and back of tongues of C57 mice were significantly reduced when a single dose of X⁃ray ex⁃ceeded 17 Gy.Conclusion C57 mice can be used for the study of a radiation⁃induced oral mucositis model when the heads and necks of mice are irradiated by 17 Gy X⁃ray.