UVC因素对DMBA诱导的小鼠皮肤肿瘤建模的影响

Effect of UVC on DMBA-induced skin tumor in mice

目的观察短波紫外线(UVC)照射对7,12-二甲基苯蒽(DMBA)诱导的皮肤肿瘤建模的效应。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(56 mJ/cm2),隔天1次,8周结束;DMBA/丙酮液(100μg/200μL)外涂,每周1次,共7次,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-荷瘤数动态变化图;皮肤组织病理学观察肿瘤形成及光损伤后的皮肤改变,并用计算机图像分析系统定量分析。结果单纯UVC照射组无肿瘤出现;UVC联合DMBA模型组小鼠6周后背部开始出现典型的上皮乳头状瘤,第9周荷瘤率达到100%,至11、12周荷瘤数渐趋稳定,平均荷瘤数为(4.57±3.0)个,肿瘤平均体积为(44.91±4.6)mm3。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作用因素,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,可较快速地建立荷瘤率高、瘤体数量稳定的皮肤肿瘤模型,较单纯DMBA建模效果好。

Objective To study the effect of ultraviolet C（UVC） on DMBA-induced skin tumor in mice.Methods Two-factor completely randomized design was adopted in this study.Light-sensitive BALB/c mice were irradiated with UVC（56 mJ/cm2） for every other day and treated with 7,12-DMBA（100 μg/200 μL） weekly for 7 weeks on dorsal skin after hair removed.The size and diameter of tumor were measured weekly.A dynamic growth curve of time-number of tumor was depicted.Skin histopathology was checked to observe the tumorigenesis.Skin morphologic changes were analyzed by computer image system.Results Mice treated with UVC and DMBA began to form typical epithelial papilloma at 6 week.The rate of tumor-bearing mice was up to 100% at 9 week.The number of tumors developed rapidly and then gradually stabilized to 4.57±3.0 at 11-12 week.The average tumor volume was up to 44.91±4.6 mm3.However,the number of tumors in DMBA-treated group reached to the peak at 8.5 week,and was unstable which showed a higher spontaneous regression rate when compared with the UVC and DMBA-treated group.Conclusion DMBA is a critical factor in establishing the skin tumor model.UVC as an independent factor failed to induce skin tumor in the 12-week period.However,the combination of UVC with DMBA exhibits the synergy effect on establishment of the skin tumor in mice.