放射性口干症动物模型建立及颌下腺放射性组织损伤的生物学效应

Modeling and biological effects of radiation-induced xerostomia

背景:目前对于唾液腺的放射性损伤机制还未明确,治疗和防护措施也处于探索阶段。目的:建立放射性口干症大鼠模型,并观察18 Gy电子线照射后大鼠颌下腺组织损伤情况及唾液成分变化。方法:通过随机对照实验,将115只Wistar大鼠随机分成照射组和假照射组,假照射组只麻醉不照射,照射组麻醉后使用直线加速器一次性照射18 Gy。将大鼠颌下腺部位暴露于照射区,制备放射性口干症模型。记录造模后21 d内饮水量;分1,3,7,14,21,28,35,42 d 8个时间点收集唾液、摘取颌下腺腺体,测量唾液量、颌下腺指数,对颌下腺切片行苏木精-伊红染色观察组织形态学变化。结果与结论:(1)放射后1-21 d照射组大鼠每天平均饮水量为(6.42±1.91)m L,假照射组为(4.82±1.20)m L,差异有显著性意义(P<0.05);(2)在放射后42 d内照射组唾液量均少于假照射组,其中照射组大鼠照射后第7天唾液量降至最低;7,21,28,42 d比较差异有显著性意义(P<0.05);(3)1 d及21-42 d,照射组颌下腺指数均小于假照射组(P<0.05);(4)苏木精-伊红病理结果显示,照射组大鼠颌下腺炎性浸润、腺体萎缩、核固缩等损伤情况呈渐进性加重,放射后42 d损伤最为严重;(5)综上,Wistar大鼠接受直线加速器电子线18 Gy照射后,放射性口干症模型成功建立,直观表现为饮水量增加,唾液量减少,病理切片显示颌下腺病理损伤程度在42 d内随时间的增加呈进行性加重。

BACKGROUND： There is little information available in the mechanism of radiation-induced salivary gland injury, and itstreatment and prevention are still at the exploratory stage.OBJECTIVE： To establish a rat model of radiation-induced xerostomia with 18 Gy electron beam and to observe thepathological changes of the submandibular gland and changes in saliva ingredients.METHODS： Totally 115 Wistar rats were randomly divided into exposure and control groups： the rats in the exposuregroup were subjected to anesthesia, and the submandibular gland received 18 Gy electron beam radiation to establishthe model of radiation-induced xerostomia. The rats in the control group were only anesthetized but not exposed toradiation. The water intake was recorded at 21 dys after modeling. The saliva was collected and the submandibulargland was removed at 1, 3, 7, 14, 21, 28, 35 and 42 days to detect the saliva volume and submandibular gland index,and the morphological changes of the submandibular gland were observed by hematoxylin-eosin staining.RESULTS AND CONCLUSION： At 1-21 days after modeling, the average daily water intake was （6.42±1.91） mL in theexposure group and （4.82±1.20） mL in the control group, respectively （P 〈 0.05）. During 42 days after modeling, thesaliva secretion volume in the exposure group was lower than that in the control group, which was the lowest on day 7,and the difference was significant at 7, 21, 28 and 42 days after modeling between two groups （P 〈 0.05）. Thesubmandibular gland index in the exposure group was significantly lower than that in the control group at 1 and 21-42days after modeling （P 〈 0.05）. Hematoxylin-eosin staining results showed that in the exposure group, the ratsubmandibular gland appeared with inflammatory infiltration, glandular atrophy and karyopyknosis that were aggravatedwith time until day 42. To conclude, the rat model of radiation-induced xerostomia is established successfully with 18 Gybeam, characterized as increased water intake, decreased saliva volume and progressive aggravation of pathologicalinjury of the submandibular gland.