体外条件下不同乳酸菌对旅行者腹泻的干预机制

Intervention mechanism of different lactic acid bacteria on traveler's diarrhea in vitro

为探究乳酸菌对旅行者腹泻(TD)的干预机制,该研究采用HT-29细胞及肠道菌群批量发酵模拟系统考察乳酸菌拮抗产肠毒素大肠杆菌(ETEC)损伤肠道屏障效果。结果表明,植物乳杆菌(Lactobacillus plantarum)LP45、嗜酸乳杆菌(Lactobacillus acidophilus)La28、鼠李糖乳杆菌(Lactobacillus rhamnosus)LR519、乳双歧杆菌(Bifidobacterium lactis)BAL531及嗜热链球菌(Streptococcus thermophilus)S131、S709能够抑制ETEC生长并特异性缓解其造成水通道蛋白(AQP-3)、紧密连接蛋白、黏蛋白(MUC2、MUC5AC)表达下调,同时对白细胞介素-8(IL-8)分泌上调和肠上皮细胞凋亡有一定缓解作用。菌株S131抑制ETEC生长和促进HT-29细胞增殖的效果最好,菌株LP45使AQP-3信使核糖核酸(mRNA)相对表达显著提升(2.77±0.60)倍(P<0.05),菌株S869使IL-8分泌显著下降(35.07±3.19)%(P<0.05),菌株LP45和S709使MUC2、MUC5AC(mRNA)相对表达分别显著提升(2.39±0.15)、(1.89±0.21)倍(P<0.05);菌株S869分别使ZO-1、occludin mRNA相对表达显著上调(15.24±0.93)倍、(9.06±0.09)倍(P<0.05),菌株LR519和BAL531分别使ZO-2 mRNA相对表达显著上调(14.83±1.60)、(13.27±1.01)倍(P<0.05)。综上,乳酸菌可缓解ETEC造成的肠道屏障损伤。

In order to explore the intervention mechanism of lactic acid bacteria on traveler's diarrhea(TD),the antagonistic effect of lactic acid bacteria on intestinal barrier damage caused by enterotoxigenic Escherichia coli(ETEC)was investigated by simulation system of batch fermentation with HT-29 cells and intestinal flora.The results showed that Lactobacillus plantarum LP45,Lactobacillus acidophilus La28,Lactobacillus rhamnosus LR519,Bifidobacterium lactis BAL531,and Streptococcus thermophilus S131 and S709 could inhibit the growth of ETEC,and specifically alleviate the expression down-regulation of aquaporin-3(AQP-3),tight-junction protein and mucin(MUC2 and MUC5AC).At the same time,it could alleviate the secretion up-regulation of interleukin-8(IL-8)and intestinal epithelial cell apoptosis.Strain S131 had the optimal effect on inhibiting ETEC growth and promoting HT-29 cells proliferation.Strain LP45 significantly increased the relative expression of AQP-3 messenger ribonucleic acid(mRNA)by(2.77±0.60)times(P<0.05).Strain S869 significantly decreased IL-8 secretion by(35.07±3.19)%(P<0.05),and strain LP45 and S709 significantly increased the relative expression of MUC2 and MUC5AC(mRNA)by(2.39±0.15)and(1.89±0.21)times(P<0.05),respectively.Strain S869 significantly up-regulated the relative mRNA expression of ZO-1 and occludin by(15.24±0.93)and(9.06±0.09)times(P<0.05),respectively.Strains LR519 and BAL531 significantly up-regulated the relative expression of ZO-2 mRNA by(14.83±1.60)and(13.27±1.01)times(P<0.05),respectively.In conclusion,lactic acid bacteria could alleviate the intestinal barrier damage caused by ETEC.