The Development of Model System for Maxillary Cancer

上颌癌动物模型的建立是本研究的主要目的，因为目前还没有可靠的系统来选择性地在鼻腔和副鼻窦诱导肿瘤。提出了两种新方法。首先，将溶解于二甲亚砜（DMSO）中的0.5% 9,10-二甲- 1,1,2 -苯并蒽（DMBA） 25mu1注射于仓鼠左上颌窦，每周1次，连续10周。之后，仓鼠不接受治疗10周。83%（10/12）的仓鼠在鼻腔和副鼻腔注射侧诱发癌。而用DMSO治疗的12只仓鼠没有出现肿瘤。其次，将2%的DMBA注射到先前已插入氧纤维素的左侧上颌窦一次。给药16周后，3只仓鼠左颊区肿胀明显，实验终止。上颌肿瘤在73%（8/11）的仓鼠中被证实为肉瘤。当我们尝试用已发表的方法，即皮下注射二乙基亚硝基源诱导上颌癌时，肿瘤被诱导，但癌症并不经常被证实。上述结果提示上颌窦反复注射0.5% DMBA是诱导鼻腔和鼻副腔鳞状细胞癌的可靠方法。采用仓鼠颊袋模型，探讨表皮生长因子（EGF）在口腔癌发生中的作用。用0.5% DMBA涂抹仓鼠颊袋，每周2次，连续6周。然后，对仓鼠进行涎腺切除术、下颌下腺切除术或假手术。随后，用EGF（10mug/kg体重）或车辆治疗脸颊袋，每周3次，持续6周。在14周时，egf处理的仓鼠颊袋肿瘤的平均数量明显高于载体处理的仓鼠。因此，在颌下腺中合成的EGF促进了dba诱导的颊袋肿瘤的发展。然而，EGF可能不会促进乳头状瘤细胞的恶性转化，因为EGF并没有增加肿瘤中癌变的比例。少

Development of an animal model for maxillary cancer is the major object of this study, because there are no reliable systems to induce tumors selectively in the nasal and paranasal cavities. Two novel methods were conducted. First, 25mu1 of 0.5% 9,10-dimethy1-1,2-benzanthracene (DMBA) dissolved in dimethyl sulfoxide (DMSO) was injected into the left maxillary sinus of the hamsters once weekly for 10 weeks. Thereafter, hamsters were left untreated for 10 weeks. Carcinomas were induced in 83%(10/12) of the hamsters at the injected side of nasal and paranasal cavities. whereas tumors were not demonstrated in 12 hamsters treated with DMSO.Second, 2% DMBA was injected once into the left maxillary sinus in which oxycellulose had been inserted previously. Sixteen weeks after the DMBA administration, three hamsters showed prominent swelling in the left buccal area and the experiment was terminated. Maxillary tumors were demonstrated in 73%(8/11) of the hamsters and were found to be sarcoma his … More tologically. When we attempted to induce maxillary cancer with the use of published method, i.e., subcutaneous injection of diethylnitrosoures, tumors were induced, but carcinoma was not frequently demonstrated. These findings indicate that repeated injection of 0.5% DMBA into the maxillary sinus is a reliable method to induce squamous cell carcinoma in the nasal and paranasal cavities.The role of epidermal growth factor (EGF) in the oral carcinogenesis was investigated with the use of hamster cheek pouch model. The cheek pouches of the hamsters were painted with 0.5% DMBA twice weekly for 6 weeks. Thereafter, sialoadenectomy, removalf submandibular glands, or sham operation was performed in the hamsters. Subsequently, cheek pouches were treated with EGF(10mug/kg body weight) or vehicle thrice weekly for a further 6 weeks. At 14 weeks, the mean number of cheek pouch tumors in the EGF-treated hamsters was significantly higher than that in the vehicle-treated hamsters. Thus, EGF synthesized in the submandibular glands enhances the development of DMBA-induced cheek pouch tumors. However, EGF may not promote the malignant conversion of papilloma cells, because EGF did not increase the proportion of carcinomas in the tumors. Less