异常隐窝病灶与大肠肿瘤关系及发生途径的初步研究

Microscopic and molecular characteristics of aberrant crypt foci and early colon cancer in rat models

目的实体镜下连续观察Wistar鼠大肠癌模型中异常隐窝病灶（ACF）的发生情况，探讨ACF与大肠肿瘤的相关性及其发生途径。方法60只Wistar鼠给予二甲肼皮下注射，每周1次，连续18周，分组处死。将美蓝染色后的大肠组织在实体镜下观察。结果发现2种不同镜下表现的ACF，即cACF和dACF。dACF与大肠肿瘤形成早期有相似的镜下形态及病理特点，而cACF则无类似特征。cACF与dACF在β—catenin中的表达异常率分别为4．8％和100．0％（P=0．000），在MMP-7中的阳性表达率分别为7．9％和81．8％（P=0．000），dACF与肿瘤在β—catenin的表达异常率以及在MMP-7的阳性表达率上的差异均无统计学意义（P〉0．05）。结论cACF与肿瘤发生无明显相关，dACF与肿瘤发生关系密切，其发生遵循Wnt途径。

Objective To evaluate the relationship between aberrant crypt foci （ACF） and colon cancer by observing the sequential development of ACF in cancer models of rats. Methods The colon cancer models in 60 Wistar rats were established by subcutaneously injection of dimethylhydrazine （DMH） once a week for 18 weeks. The rats were sacrificed and the colon tissues stained by methylene blue were observed with a stereomicroscope. Results There were two types of ACF, named cACF and dACF. The microscopic findings in dACF were similar with that in early colon cancer, while those in cACF were not. The expression of β-catenin in cACF and dACF were 4. 84% and 100% （P =0. 000） , respectively, and the expression of MMP-7 were 7.87 % and 81.82 % （ P = 0. 000 ） , respectively. There was no significant difference in expression of β-catenin and MMP-7 between dACF and colon cancer （ P 〉 0. 05 ）. Conclusion The microscopic and molecular changes in dACF is similar with that in colon cancer, and dACF may progress to cancer through Wnt pathway.