皮肤光损伤肿瘤模型的建立

目的模拟人皮肤肿瘤形成的自然环境因素，建立光损伤小鼠皮肤肿瘤模型。方法采用完全随机的两因素析因设计。选择对光线敏感的BALB／c小鼠，背部皮肤脱毛后UVC照射（56mJ／cm2），隔天1次，8周结束；二甲基苯蒽／丙酮液（100μg／200μL）外涂，每周1次，共7周，12周后处死。连续测量并记录小鼠背部肿瘤数量和直径，描绘时间一荷瘤数动态变化图；皮肤组织病理学观察肿瘤形成的组织细胞形态学改变。结果单纯UVC照射组无肿瘤出现；UVC＋DMBA模型组小鼠6周后背部开始出现肉眼可见的瘤体，第9周荷瘤率达到100％，11、12周荷瘤数渐趋稳定，肿瘤体积有增大趋势，平均荷瘤数为（4．57±3．0）个，肿瘤平均体积为（44．91±4．6）mm。。HE染色、瑞氏染色、基底膜带染色均显示为早期皮肤鳞状细胞癌。而单纯DMBA组荷瘤数第8．5周达高峰，后呈下降趋势，肿瘤自然消退率高，数量不稳定。结论DMBA是皮肤肿瘤建模的主要因素，但停止该处理因素后荷瘤数量呈下降趋势；UVC作为一个独立因素，在12周内未能诱导出皮肤肿瘤，但UVC与DMBA联合应用具有交互协同作用，可较快速地建立皮肤肿瘤模型。该模型具有出瘤率高，出瘤整齐，荷瘤量多，除去处理因素后瘤体数量依旧稳定，且体积有增大趋势等特点，为皮肤肿瘤的防治研究提供有价值的实验工具。

Establishment of skin tumor models induced by photo-damage and 7,12-DMBA in mice

Objective To simulate natural environmental factors of human skin tumor formation to establish photo- damaged skin tumor models in mice. Methods The study was designed by completely randomized factorial design. BALB/c mice that are light-sensitive were irradiated by UVC （56 mJ/cm2） every other day for 8 weeks and were treated topically with 100 p~g of DMBA in 200 IxL of acetone once a week until 7 weeks on the dorsal skin area after hair removed. The whole process was 12 weeks. The size and diameter of tumors were observed and measured every week. A dynamic growth-curve of tumor-bearing was depicted. The histopathology features of skin dyed by HE staining, Wright＇ s staining and basement membrane were observed to explore Tumor formation and skin morphologic alteration. Results The mice in model group began to form typical epithelial papilloma at 6 week early and the rate of tumor-bearing were up to 100% at 9 week. Then, the number of tumor-bearing developed rapidly and gradually stabilized at 11 - 12 week to the average number of tumor-bearing up to （4.57 ＋ 3.0） and the average tumor volume up to （44. 91 -＋ 4.6） mm3. However, the time of tumor happening in DMBA group mice was earlier than model group. The number of tumor-bearing in DMBA group reached a peak at 8.5 week, and then, had a downward trend. Furthermore, tumor spontaneous regression rate were high and the number of tumor-bearing were unstable. Conclusion DMBA is a main factor of the skin tumors modeling. UVC as an independent factor failed to induce skin tumors in the 12-week period. However, the combination of UVC with DMBA has interactive synergy effects on establishment of skin tumor models, which have excellent characteristics of high rate of tumor- bearing, time unified, the large number of harvest and good stabilization. It is a straight, stable and simple experimental tool for anticancer drugs and mechanism study on skin tumor.