反流性食管炎黏膜上皮中紧密连接蛋白及白细胞介素-6的表达

Expressions of tight junction proteins and interleukin-6 in mucosa of reflux esophagitis

目的观察反流性食管炎（RE）大鼠食管黏膜中紧密连接蛋白（闭锁蛋白、跨膜蛋白、胞质附着蛋白-1和连接粘附因子1）的分布和表达，以阐述紧密连接蛋白在RE发病机制中的作用。方法雄性8周龄Wistar大鼠220只，分成假手术对照组（10只）、酸反流组（70只）、碱反流组（70只）和酸碱混合反流组（70只）。动物于术后3、6、9、14d分批处死，取食管中、下段评估成模率。以透射电镜成像法观察紧密连接形态学的变化。分别用免疫组化法、Western印迹法和RT—PCR法检测白细胞介素（IL）-6、紧密连接蛋白及其mRNA的表达。结果造模成功率为100％。显微镜下观察发现随着RE的发展，黏膜厚度增加。电镜下可见细胞间隙增宽，桥粒明显减少。模型组IL-6和紧密连接蛋白的表达明显高于对照组，但随着基底层细胞增殖改变的加重，单个细胞间紧密连接蛋白的表达逐渐降低。随着RE病程的发展，IL-6和紧密连接蛋白及其mRNA的表达逐渐增强。结论紧密连接蛋白高表达参与了RE的发病机制，是RE发生、发展的早期分子事件。其表达可能在RE的病理过程中具有正调节的协同作用，而IL-6是RE发展演进过程中的致炎因子。

Objective To investigate the distribution and expression of tight junction proteins （including claudin 1, occludin,ZO-1 and JAM-1） in mucosa of rats with reflux esophagitis （RE）, and its underline mechanism in pathogenesis of RE. Methods Two hundred and twenty 8-week-old male Wistar rats were divided into sham operation control group （n= 10）, acid reflux group （n= 70）, alkaline reflux group （n= 70） and mixed reflux group （n=70）. The rats were sacrificed at day 3, 6, 9 and 14 after operation. The successful rate of modeling was assessed by evidence of inflammation in middle and low esophagus. Transmission electron microscopy （TEM） was used to observe the morphological changes of tight junction in esophageal epithelium. The mRNA and protein expressions of tight junction proteins were detected by Western blotting and RT-PCR, respectively. And interleukin （IL） 6 expression was measured by immunohistochemistry. Results At day 14 after the procedure, RE model was established in all executed rats. Successful rate of 100% was achieved. The microscopic observation showed that mucosa was damaged and thickened as the disease progressed. With TEM observation, widened intercellular space was noticed with fewer desmosomes. Elevated expressions of IL-6 and tight junction proteins were found in three model groups compared with control group. Whereas the expression of tight junction proteins in individual cells was gradually decreased with continuing hyperplasia in the basal layer. The mRNA and protein expressions of IL-6 and tight junction proteins were increased gradually as disease progressed. Conclusions The highly expression of tight junction proteins, which involves in the mechanism of RE by playing the role of positive regulation and synergism, may be early molecular event in development of RE. And IL-6 is an inflammatory factor in this process.