不同营养方式对梗阻性黄疸大鼠肠紧密连接蛋白的影响

目的 观察肠内营养(EN)及肠外营养(PN)对阻塞性黄疸(OJ)大鼠小肠紧密连接蛋白的影响.方法 将50只Wistar大鼠随机分5组,EN组和PN组给予等热量等氮量营养.7 d后采用免疫组织化学和Western blot法检测各组末端回肠黏膜的闭锁小带-1(ZO-1)、闭锁蛋白(Occludin)与肌球蛋白轻链激酶(MLCK)的表达,并对Western blot图像进行定量分析.结果 正常回肠黏膜ZO-1和Occludin沿绒毛下方均匀连续分布,MLCK主要分布在细胞质内.阻黄时ZO-1、Occludin和MLCK分布散乱,染色稀疏.PN组的ZO-1、Occludin和MLCK的强阳性染色数由阻黄组的2、2、1例升至4、5、3例(P均>0.05),而EN组的强阳性染色数分别上升为7、6、5例(P均<0.05).通过对Western blot显影图像进行定量分析,EN组和PN组的ZO-1的灰度值较阻塞性黄疸组明显上升(均P<0.05);Occludin和MLCK的灰度值在EN组上升(P<0.05),PN组没有变化.结论 梗阻性黄疸时大鼠小肠黏膜上皮ZO-1、Occludin和MLCK分布紊乱,表达下降.肠内、外营养均能够恢复受损的紧密连接蛋白,肠内营养的作用更强.

Effects of different nutrition patterns on tight junction proteins in rats with obstructive jaundice

Objective To observe the effects of enteral nutrition (EN) and parenteral nutrition (PN) on tight junction proteins in rats with obstructive jaundice (OJ). Methods Fivty Wistar rats were randomly divided into five groups. In PN group and EN group nutritional formulae were given with equal calorie and nitrogen. After 7 days, immunohistochemistry and Western blot were used to examine the distribution and expression of ZO-1, Occludin and myosin light chain lcinase (MLCK) in distal ileum mucosa. The Western blot images were analysed quantitatively. Results In normal group, the ZO-1 and Occludin exhibited a continuous and uniform distribution nearby the apical lateral membrane, and MLCK was distributed mainly in cytoplasm. In OJ group, their stainings were discontinuous and vague. Compared with OJ group, there was no significant difference in the amounts of strong positive expression of ZO-1, Occludin and MLCK in PN group (2 vs 4,2 vs 5, and 1 vs 3 respectively, all P > 0.05) , but the amounts of strong positive expression of ZO-1, Occludin and MLCK were rose to 7,6 and 5 in EN group (all P < 0. 05). By quantitative analysis of the Western blot images, the gray values of ZO-1 were significantly increased in PN and EN groups (P < 0. 05), those of Occludin and MLCK were increased in EN group (P < 0. 05) , but unchanged in PN group (P > 0.05) as compared with OJ group. Conclusion Obstructive jaundice down-regulated the expression of ZO-1, Occludin and MLCK in rat ileum. Both EN and PN could recover impaired tight junction proteins. The effects were stronger in EN.