Histogenesis of Rat Lung Tumors induced by N-Nitrosodiethylamine (DEN)

1. DEN组和DEN+PIP组均出现肺肿瘤形成。对照组、DEN组和DEN+PIP组治疗32周的平均可见肿瘤结节数分别为0、3、4.5个，治疗48周的平均可见肿瘤结节数分别为0.5、16、7个。以DEN 48周组最多，但与其他各组比较差异无统计学意义. 32周时，在肺泡区发现不典型腺瘤样增生、高分化腺癌和两者混合的肿瘤性病变。在细支气管区末端的肿瘤的乳头状增殖和它们向邻近肺泡腔的生长也被识别，这表明它们是细支气管上皮细胞起源的。48周时，肿瘤组织中出现多个肿瘤样病变，包括腺癌，细胞多形性严重，核分裂像散在.免疫组化SP-A在治疗32周和48周大鼠的肿瘤细胞中表达。与此相反，即使在Clara样肿瘤细胞中，在所有肿瘤细胞中也没有识别出明显的CC 10反应性，这表明肿瘤细胞中CC 10表达的抑制。PCNA标记指数（L.I.）(the DEN+PIP治疗32周组、DEN+PIP治疗48周组和DEN+PIP治疗48周组的阳性肿瘤细胞数/1000个肿瘤细胞分别为167.5、159.5、364和174。DEN 48周治疗组的平均数在统计学L.I.in匹配. DEN+PIP治疗48周组的PCNA平均数L.I.in

1. We found the formation of lung tumors in the all rats of DEN and DEN+PIP group. The mean number of grossly visible tumor nodules in controle, DEN and DEN+PIP group was 0, 3, 4.5 in 32 week treatment rats and 0.5, 16, 7 in 48 week treatment rats, respectively. The number of DEN 48 week group was the highest, but there was no statistical significance among the number and those of other groups.2. At 32 weeks the tumorous lesions of atypical adenomatous hyperplasia, well differentiated adenocarcinoma and the admixture of both the two lesions were found in the alveolar region. The papillary proliferation of tumors at the end of the bronchiolar region and their growth to the adjacent alveolar spaces were also recognized, suggesting their bronchiolar epithelial cell origin. At 48 weeks multiple tumorous lesions consisting of adenocarcinoma with severe cellular pleomorphism and scattered mitotic figures were noticed.3. Immunohistochemically the SP-A was expressed in the tumor cells of both 32 and 48 week treatment rats. In contrast to this no apparent CC10 reactivity was recognized in all tumor cells even in the Clara like tumor cells, which suggests the depression of CC10 expression in the tumor cells.4. The mean number of PCNA Labeling Index (L.I.) (the number of positive tumor cells/1000 tumor cells) in each groups was 167.5 in DEN 32 week, 159.5 in DEN+PIP 32 week, 364 in DEN 48 week and 174 in DEN+PIP 48 week treatment group. The mean number of L.I.in DEN 48 week treatment group was statistically higher then that of any other groups, and this was well matched the tendency of tumor formation.5. The mean number of PCNA L.I.in DEN+PIP 48 week treatment group was statistically lower than thet of DEN 48 week treatment group, and from this and the tendency of lower tumor formation in DEN+PIP than that in DEN treatment group the inhibition of DEN induced tumorigenesis by PIP was suggested.