大鼠实验性口腔癌前病变模型的建立及意义

目的：观察致癌剂作用后大鼠口腔粘膜改变过程．方法：57只Wistar大鼠随机分为3组，即正常对照组(12只)、诱癌组(27只)和丙二醇组(18只)，诱癌组用O．5％4-硝基喹啉-1-氧化物(4-NQ0)丙二醇液涂抹腭中部每周3次，丙二醇组仅用丙二醇涂抹，正常对照组不处理．实验开始后第8，12和20周随机分别处死4，9及6只动物，并进行组织学及增殖指数评价．结果：随着4-NQ0涂药周次的增加，大鼠腭粘膜出现充血发红，增厚发白，细颗粒状，糜烂溃疡等改变，组织学上8周时大部份动物呈单纯增生(89．0％)，少部份呈异常增生改变；12周时所有动物呈轻到重度异常增生；20周时呈原位癌至高分化鳞癌的改变．增殖细胞核抗原(PCNA)标记指数表明随着癌变发生，上皮细胞增殖指数也增加．结论：采用4-NQO可诱发大鼠腭粘膜发生与人类口腔鳞癌相似病损，12周时段可作为癌前病变模型．

Study of Experimental Animal Model of Oral Precancerous Lesions in Rats

Objective: To establish an experimental animal model of oral precancerous lesions in rats. Methods: 57 Wistar rats were randomly divided into experimental group ,control group and propylene glycol group. The 0.5% 4-nitroquinoline 1-oxide( 4-NQO) in propylene glycol was painted on middle palate three times per week in experimental group rats, prolylene glycol group was painted with prolylene glycol only,the control group was left unpainted .Groups of animals were killed at intervals ranging from 8,12 and 20 weeks after the first painting. Their palatal mucosa were removed for histopathological and proliferative cell nuclear antigene(PCNA) label index(PI) assessment. Results: The palate in rats treated with 4-NQO for 8 weeks showed hyperplasia (89.0%) and mild dysplasia (11.0%); those for 12 weeks showed mild dysplasia (11.0%) and moderate dysplasia (66.7%) and severe dysplasia (22,3); those for 20 weeks showed in situ carcinoma to well-differentiated invasive squamous cell carcinoma. The severity of lesions and PI corresponded to the duration of 4-NQO painting.Conclusion: In the rat palate model, continuous application of 4-NQO for 12 weeks results in moderate or severe dysplasia.The results indicate that 4-NQO reliably produced preneoplastic palate mucosa lesions, which morphologically and histologically mimic human oral carcinogenesis,and 12 weeks is the best time for observation of oral precancerous lesions.