益生菌VSL#3及布拉氏酵母菌对急性结肠炎模型小鼠肠道菌群的影响

Effect of VSL#3 and S.Boulardii on intestinal microbiota in mice with acute colitis

目的探讨益生菌(VSL#3、布拉氏酵母菌)对急性结肠炎模型小鼠肠道菌群的影响。方法C57BL/6J小鼠分为4组,除空白对照组外,其余3组小鼠饮用2.5%的葡聚糖硫酸钠(DSS)5 d建模,DSS建模组饮用水灌胃,其余2组分别予VSL#3、布拉氏酵母菌灌胃,建模结束后2 d处死各组小鼠。收集灌胃前(第0天)、实验中期(第4天)及灌胃结束(第7天)的粪便标本及处死后的肠黏膜组织,送检16s rDNA基因测序并统计分析。结果VSL#3组与DSS建模组比较,疾病活动度(DAI)及组织学病理评分下降,布拉氏酵母菌灌胃组没有显著变化。粪便菌群:实验中期,DSS建模组、VSL#3组及布拉酵母菌组小鼠粪便菌群多样性均低于空白对照组(P=0.013 5,P=0.001 8,P=0.015 1)。灌胃结束后,VSL#3组多样性低于空白对照组(P=0.025),其余两两组间比较差异无统计学意义。肠黏膜菌群:DSS建模组、布拉氏酵母菌组多样性低于与空白对照组(P=0.031,P=0.043 7),VSL#3组多样性高于DSS建模组及布拉氏酵母菌组(P=0.039 4,P=0.042 6)。DSS建模组与空白对照组比较,实验中期、灌胃结束后的粪便菌群和黏膜菌群均拟杆菌属增加,乳杆菌属减少。实验中期小鼠粪便菌群中,DSS建模组较空白对照组厚壁菌门Turicibacter属、拟杆菌门Odoribacter属显著增多,而VSL#3灌胃组较DSS建模组两者丰度显著减少。结论VSL#3对DSS诱导的小鼠急性结肠炎有较明显的缓解作用,VSL#3及布拉氏酵母菌均可影响肠道菌群。与正常小鼠相比,结肠炎建模小鼠粪便菌群及黏膜菌群多样性降低,VSL#3增加黏膜菌群多样性,但不增加粪便菌群多样性。急性结肠炎模型小鼠中Turicibacter、Odoribacter等菌属增多,这些菌属可被VSL#3抑制。

Objective To investigate the effects of probiotics(VSL#3,S.Boulardii)on intestinal flora of mice with DDS-induced acute colitis.Methods C57BL/6J mice were administered with 2.5%dextran sulfate sodium for 5 consecutive days to develop the acute colitis model except for the blank control group.Meantime,Mice were treated with drinking water(DSS model group),VSL#3(1.5×109 CFU),or S.Boulardii(5×107 CFU)by gavage for 7 days respectively,and mice were sacrificed 2 days after the model of colitis was established.The fecal specimens before gavage(day 0),in the middle of experiment(day 4),and the end of gavage(day 7)and the intestinal mucosa after sacrifice were collected to analyze the differences between these four groups by 16s rDNA sequencing method.Results Compared with the DSS model group,VSL#3 group showed a decrease in disease activity index(DAI)and histological scores,and there was no significant change in the S.Boulardii group.Fecal microbiota:in the middle of experiment,the alpha diversity of DSS model group,VSL#3 group and S.Boulardii group were lower than that of the blank control group(P=0.0135,P=0.0018,P=0.0151).After the end of gavage,the diversity of the VSL#3 group was lower than that of the blank control group(P=0.025),and the difference between any other two groups was not statistically significant.Mucosa-adherent microbiota:biodiversity of DSS model group,S.Boulardii group were lower than the blank control group(P=0.031,P=0.0437),while biodiversity of VSL#3 group was higher than DSS model group and S.Boulardii group(P=0.0394,P=0.0426).Compared with the blank control group,the DSS model group showed an increase in Bacteroides and a decrease in Lactobacillus.Abundance in the genus Turicibacter and Odoribacter increased in intestinal microbiota of mice with acute colitis,while VSL#3 inhibited them.Conclusions VSL#3 alleviates inflammation in DSS-induced colitis of mice.Both VSL#3 and S.Boulardii can affect intestinal microbiota.Compared with healthy mice,mice with colitis showed a reduced diversity of microbiota both in feces and in intestinal mucosa.VSL#3 increases biodiversity of mucosal microbiota in mice with acute colitis,while it does not increase biodiversity of fecal microbiota.Genera such as Turicibacter and Odoribacter increase in mice with acute colitis,and these genera can be inhibited by VSL#3.