益生菌对急性胰腺炎大鼠肠道微生态及紧密连接的影响

Effects of Probiotics on Gut Microflora and Barrier Function of Rats with Acute Pancreatitis

目的探讨经肠道补充益生菌对急性胰腺炎(AP)大鼠肠上皮细胞紧密连接、屏障功能及微生态的影响。方法经胰管注射3%牛磺胆酸钠造成大鼠AP后,分别给予肠外营养(PN组)和PN+益生菌(益生菌组),持续5天;第6天处死大鼠,取腔静脉血、肺及肝组织和肠系膜淋巴结匀浆作细菌培养测细菌易位率;取末段回肠和结肠,采用免疫组织化学法测定其跨膜结合蛋白表达,电镜观察肠上皮细胞紧密连接超微结构;取盲肠内粪便作厌氧培养及细菌种群DNA指纹图谱分析。结果益生菌组大鼠肠道内乳杆菌和双歧杆菌数量高于PN组(P<0.05),而潜在致病菌产气荚膜梭菌低于PN组(P<0.05),DNA指纹图谱也显示益生菌组优势菌群的基因条带和正常大鼠具有较高一致性,与PN组相比则有明显差异;益生菌组小肠和大肠跨膜结合蛋白的表达明显优于PN组(P=0.001,P=0.036),肠上皮细胞紧密连接、微绒毛较完整;益生菌组大鼠的血、肺、肝、肠系膜淋巴组织的细菌易位率低于PN组(P=0.0413)。结论益生菌能纠正AP大鼠PN时肠道菌群紊乱,增加肠上皮跨膜结合蛋白表达,维持肠上皮紧密连接,减少细菌易位。

To investigate the effect of probiotics supplement by gut on intestinal epithelial tight junctions, barrier function, and the microecology of the rats with acute pancreatitis （AP）. Methods After the AP model was made in 24 SD rats, these animals were randomly divided into parenteral nutrition （PN） group and PN ＋ probiotics group （probiotics group）. Nutrients were administered via the needle jejunostomy and neck vein for five days. Vena cava blood and the homogenated tissue of liver, lung, and mesenteric lymph nodes were cultured to determine the bacterial translocations. The transmembrane binding proteins （occludin） were measured with immunohistochemistry. The ultrastructure of intestinal epithelial tight junctions in the colon and small intestine was observed by electron microscope. The feces in cecum were cultured for anaerobic bacterial growth and analysed by bacterial group DNA fingerprint spectrum. Results The amounts of lactobacteria and bifydobacteria in probiotics group was significantly higher than in PN group （ P 〈 0.05 ）, while the potentially pathogenic germs were significantly lower （ P 〈 0.05 ）. The gene stripe was highly consistent between rats in probiotics group and normal rats, but was significantly different between rats in PN group and normal rats, as shown by DNA fingerprint spectrum. In the in probiotics group, expressions of occludin at the small and large intestines were prevail to those in PN group （P =0. 001, P =0. 036） ; furthermore, the intestinal epithelial tight junction and microvilli in probiotics group were more intact when compared with PN group. The bacterial translocations of blood, liver, lung, and mesenteric lymph nodes were significantly decreased in probiotics group （P = 0. 0413）. Conclusion The probiotics may correct the intestinal flora disturbance, increase the expression of transmember binding proteins, maintain the intestinal epithelial tight junction, and decrease the occurrence of gut bacterial translocations.