益生菌改善尿毒症大鼠肠道氧化应激反应保护肠道屏障功能的研究

Probiotics improve intestinal oxidative stress to protect intestinal barrier function in uremic rats

目的探讨口服补充益生菌动物双歧杆菌乳亚种Bi-07(Bifidobacterium animalis subsp.Lactis Bi-07)是否对尿毒症大鼠肠道屏障功能具有保护作用,并探讨其是否通过改善肠道组织氧化应激而发挥生物学效应。方法将30只SD大鼠随机分成假手术组、尿毒症组、尿毒症+益生菌组,每组10只,假手术组仅打开肾包膜,尿毒症组行5/6肾切除术,尿毒症+益生菌组行5/6肾切除术后每日给予动物双歧杆菌乳亚种Bi-07灌胃,持续4周。麻醉大鼠后取空肠、回肠、结肠肠段。应用扫描电子显微镜结合硝酸镧染色观察肠道上皮紧密连接复合体的超微结构。制备肠组织匀浆,采用硫代巴比妥酸缩合法测定丙二醛含量,采用黄嘌呤氧化酶法检测超氧化物歧化酶活力。结果相对于尿毒症组,补充益生菌可恢复肠上皮细胞间紧密连接超微结构,微绒毛整齐、结构完整。对比尿毒症组,尿毒症+益生菌组肠道通透性显著降低(P<0.05),血清炎症因子超敏C反应蛋白、白细胞介素-6、肿瘤坏死因子α水平显著降低(P<0.05),肠道超氧化物歧化酶活力显著增加(P<0.05),肠道丙二醛呈降低趋势,但差异无统计学意义(P>0.05)。结论益生菌动物双歧杆菌乳亚种Bi-07可改善尿毒症大鼠肠道屏障功能,其作用机制可能为抑制肠道氧化应激反应,从而减轻尿毒症大鼠肠道屏障损伤。

Objective To investigate whether oral probiotic Bifidobacterium animalis subsp.Lactis Bi-07 protects the intestinal barrier function of uremic rats,and explore whether it plays its biological effects by improving oxidative stress in tissues.Methods Thirty SD rats were randomly divided into 3 groups(n=10),sham operation group,uremic group,uremia + probiotic group.For the sham operation group only the renal capsule was opened,and for the uremic group 5/6 nephrectomy was conducted.For the uremia + probiotic group 5/6 nephrectomy was performed and then the animals were administered with Bi-07 every day for 4 weeks.The rats were anesthetized and the jejunum,ileum and colon segments were taken out.The ultrastructure of the intestinal epithelial tight junction complex was observed by scanning electron microscopy combined with lanthanum nitrate staining.The intestinal homogenate was prepared,and malondialdehyde(MDA) content was determined by thiobarbituric acid condensation method;and superoxide dismutase(SOD) activity was determined by xanthine oxidase method.Results Compared with the uremic group,supplement of probiotics could restore the tight junction ultrastructure between epithelial cells,with neat microvilli and intact structure.Compared with the uremic group,the intestinal permeability in the uremia + probiotic group was significantly decreased(P<0.05);serum inflammatory factors hs-CRP,IL-6,TNF-α levels were significantly lower(P<0.05);the intestinal SOD level was significantly increased(P<0.05);and the intestinal MDA showed a decreasing trend,but the difference was not statistically significant(P>0.05).Conclusions Bi-07 can improve intestinal barrier function in uremic rats.The mechanism may be realized by inhibiting intestinal oxidative stress so as to reduce intestinal barrier damage in uremic rats.