Histopathological study of Barrett's adenocarcinoma using analyses of mitochondrial DNA mutations

为了阐明Barrett食管（BE）发展为食管腺癌（EAC）的组织发生，我们检测了各种病变（BE、EAC、鳞状不典型增生和鳞状细胞癌）中的线粒体DNA突变，并进行了细胞色素c氧化酶的免疫组化染色和酶组织化学。这些病变是在大鼠十二指肠内容物反流模型中诱导的，这些模型是先前报道的未经胃切除的食管空肠吻合模型。以前，我们报道了高膳食动物脂肪通过增加胆汁中牛磺酸结合物的浓度来改变胆汁酸的组成。这些增加的胆汁酸促进BE和Barrett发育不良进展为EAC的发展。本研究将反流动物模型按饮食分为两组。标准饲料组饲喂低豆油饲料（CE-2），高脂饲料组饲喂高乳脂饲料（Quick Fat）。在术后10、20和30周处死手术存活的动物。用免疫组化和酶组织化学方法对切除食管中的细胞色素c氧化酶进行了分析。细胞色素c氧化酶阴性病灶检测的情况下，证明线粒体突变，这些病灶增加的时间依赖性的方式。与标准饮食组相比，在高脂肪组中观察到的病灶数量显著更高。我们观察到细胞色素c氧化酶阴性灶首先出现在BE的增殖带，并伴有杯状细胞，然后以类似于肠腺分裂的方式增殖。在正常再生鳞状上皮中也检测到这些病灶。然而，我们不能证明BE致癌和线粒体突变之间的关系。

To elucidate the histogenesis of Barrett's esophagus (BE) progressing to esophageal adenocarcinoma (EAC), we examined mitochondrial DNA mutations and performed immunohistochemical staining and enzyme histochemistry of cytochrome c oxidase in various lesions (BE, EAC, squamous dysplasia, and squamous cell carcinoma). These lesions were induced in rat duodenal contents reflux models, which were previously reported models that had undergone esophagojejunostomy without gastrectomy. Previously, we reported that high dietary animal fat alters bile acid composition by increasing the concentration of taurine conjugates in bile. These increased bile acids promote the development of BE and Barrett's dysplasia progressing to EAC. In the present study, the reflux animal models were divided into two groups on the basis of their diet. The standard diet group was fed with a low soybean oil diet (CE-2) and the high-fat group was fed with a high cow fat diet (Quick Fat). The animals that survived the operation were sacrificed at postoperative weeks 10, 20, and 30. Cytochrome c oxidase was analyzed in the resected esophagi by both immunohistochemical staining and enzyme histochemistry. Cytochrome c oxidase-negative foci were detected in cases that demonstrated mitochondrial mutations, and these foci increased in a time-dependent manner. A significantly higher number of foci were observed in the high-fat group compared with the standard diet group. We observed that cytochrome c oxidase-negative foci first appeared in the proliferative zone of BE with goblet cells, and then proliferated in a manner similar to crypt fission of intestine. These foci were also detected in the normal regenerative squamous epithelium. However, we could not demonstrate the relationship between BE carcinogenesis and mitochondrial mutations.