经肛门直肠注射大鼠原位大肠癌模型的构建

目的：寻找一种构建动物大肠癌模型成功率高、周期短的方法,为大肠癌实验研究提供可靠的动物模型。方法：Wistar大鼠60只,随机分成三组,二甲基肼组23只,环磷酰胺组23只,对照组14只。二甲基肼组在大鼠皮下注射二甲基肼,8周后直肠黏膜下注射大肠癌细胞;对照组仅皮下注射二甲基肼8周;环磷酰胺组直肠黏膜下注射癌细胞前24h,腹腔内注射环磷酰胺。结果：直肠黏膜下注射癌细胞2周后,共52只大鼠完成实验,二甲基肼组有10只（50.0%）大鼠直肠黏膜可见癌结节形成;环磷酰胺组6只（30.0%）大鼠形成癌结节;对照组有4只（33.3%）大鼠直肠黏膜可见结节,其中,3只（25.0%）为不典型增生,1只（8.3%）为癌结节。二甲基肼组成功率较环磷酰胺组及对照组高（均P〈0.01）,环磷酰胺组与对照组差异无统计学意义（P〉0.05）。结论：在应用二甲基肼的基础上,直肠黏膜下注射大肠癌细胞可成功诱发大鼠大肠癌,并优于免疫抑制为基础的方法。

The establishment of the rat model of orthotopic colorectal cancer by transanal rectal injection

Objective：To find a high incidence and short-period method of establishing a cancer model and provide a reliable animal model for experimental study of colorectal cancer.Methods：60 Wistar rats were randomly divided into DMH group（n=23）,Cyclophosphamide group（n=23） and control group（n=12）.Rats in DMH group were injected subcutaneously with DMH,then injected submucosally with colorectal cancer cells into rectum 8 weeks later.Rats in control group were only injected subcutaneously with DMH for 8 weeks;rats in Cyclophosphamide group were injected with Cyclophos phamide into peritoneal cavity,then injected submucosally with colorectal cancer cells into rectum 24 hours later.Results：After 2 weeks of injected submucosally with cancer cells,in DMH group,10 rats（50.0%） were found cancer nodules on their mucosa;in Cyclophosphamide group,6 rats（30.0%） were found cancer nodules on their mucosa;in control group,4 rats（33.3%） were found nodules on their mucosa,3（25.0%） with atypical hyperplasia,1（8.3%） with cancer nodule.The suc cess rate of DMH group was higher than that of Cyclophosphamide group and control group（P0.01）.No significant difference was shown between Cyclophosphamide group and control group（P0.05）.Conclusion：Based on the application of DMH,injecting submucosally with colorectal cancer cells into rectum can successfully induce colorectal cancer,this method is better than that of Cyclophosphamide group.