Barkla D H, Tutton P J
Cancer Res. 1977 Jan;37(1):262-71.
Male Sprague-Dawley rats were given weekly s.c. injections of 1,2-dimethylhydrazine (21 mg/kg) for period of up to 20 weeks. The descending colon of treated animals killed at 2 weekly intervals was examined for morphological change, over a 30-week period, after commencement of treatment using scanning electron microscopy, light microscopy, transmission electron microscopy, and freeze-fracture techniques. Scanning electron microscopy showed that 1,2-dimethylhydrazine treatment resulted in the progressive replacement of the normal arrangement of epithelial cells covering the luminal surface of intestinal glands with enlarged and irregularly shaped arrangements of epithelial cells, so that the entire mucosa was atypical and disorganized at 30 weeks after commencement of treatment. The changes were not readily observable using other methods of microscopy. Multiple tumors that were apparently unrelated to sites of specific morphological change erupted into the intestinal lumen through the atypical epithelium. Tumor surface cells and normal absorptive cells were compared using scanning electron microscopy and transmission electron microscopy of thin sections and freeze-fracture replicas. The results showed that tumor cells were usually smaller, more rounded, showed less regularly shaped microvilli, and had fewer particles in the apical surface membrane than on normal absorptive cells.
将雄性斯普拉格-道利大鼠每周皮下注射1,2-二甲基肼（21毫克/千克），持续长达20周。在治疗开始后的30周内，每隔2周处死接受治疗的动物，取出降结肠，使用扫描电子显微镜、光学显微镜、透射电子显微镜和冷冻断裂技术检查其形态变化。扫描电子显微镜显示，1,2-二甲基肼治疗导致覆盖肠腺腔表面的上皮细胞正常排列逐渐被扩大且形状不规则的上皮细胞排列所取代，以至于在治疗开始30周后整个黏膜变得不典型且紊乱。使用其他显微镜检查方法不容易观察到这些变化。多个明显与特定形态变化部位无关的肿瘤通过非典型上皮突入肠腔。使用扫描电子显微镜、薄切片透射电子显微镜和冷冻断裂复制品对肿瘤表面细胞和正常吸收细胞进行了比较。结果显示，肿瘤细胞通常较小，更呈圆形，微绒毛形状不规则，顶端表面膜中的颗粒比正常吸收细胞少。
