孕期慢性应激对雌鼠和子代肠道菌群组成及多样性的影响

目的观察孕期慢性应激雌鼠及子代肠道菌群的变化,探索肠道菌群在孕期慢性应激中发挥的作用。方法于2019年11月,选择SPF级健康成年SD大鼠,16只雌鼠随机分为对照组和模型组,每组8只;12只雄鼠随机分为对照交配组(4只)和模型交配组(8只)。建立孕期慢性不可预知温和应激(CUMS)模型,雌鼠在应激前1天和应激第1、7、14、21天进行眼内眦静脉采血,利用放射免疫法测定血浆皮质酮含量;应激完成后,收集雌鼠新鲜粪便待测。两组子鼠在出生后20 d(PND20)收集新鲜粪便待测,分为对照子鼠组和模型子鼠组样品。采用Illumina Miseq测序技术,测定大鼠粪便中微生物16S rRNA V3-V4区序列,并对群落结构和多样性进行分析。结果模型组雌鼠在应激第7、14天血浆皮质酮含量均高于同期对照组雌鼠(P<0.05);与对照组比较,模型组Sobs指数、Chao指数、Ace指数、Shannon指数均降低(P<0.05);对照组所特有的物种丰度(OTU)数目为130种,模型组91种;对照组雌鼠厚壁菌门的相对丰度(64.87%)高于模型组(50.83%),而拟杆菌门的相对丰度(31.72%)低于模型组(46.35%);对照子鼠组Sobs指数、Chao指数、Ace指数、Shannon指数和Simpson指数均高于模型子鼠组(P<0.05);模型子鼠组所特有的OTU数目为75种,对照子鼠组93种;对照子鼠组厚壁菌门相对丰度(60.24%)高于模型子鼠组(52.95%)。结论孕期慢性应激不仅会引起雌鼠肠道菌群紊乱,而且可能会导致宫内环境改变,进而对子代肠道菌群的群落多样性产生影响。

Effects of chronic stress during pregnancy on composition and diversity of intestinal microbiota in female rats and offspring

Objective To investigate the effect of chronic stress of pregnant rats on the gut microbiota of female rats and offspring,and explore the role of intestinal microbiota in chronic stress during pregnancy.Methods In November 2019,SPF-grade healthy adult SD rats were selected.16 female rats were randomly divided into control group and model group,with 8 in each group;12 male rats were randomly divided into model mating group(8)and control mating group(4).A model of chronic unpredictable mild stress(CUMS)during pregnancy was established.Blood samples were collected from the iliac vein of the female rats 1 day before and 1,7,and 14 days after the CUMS protocol,and measured for plasma corticosterone content by radioimmunoassay.After the stress was completed,fresh feces of the female rats were collected for testing.The offspring's fresh stool samples were collected on postnatal day 20(PND20),and they were divided into control offspring group and model offspring group samples.The sequence of 16S rRNAV3-V4 regions of microorganisms in the feces of offspring was determined by Illumina MiSeq technique;and the interaction between microbial community structure and diversity were analyzed.Results The content of plasma corticosterone in the model group was higher than that in the control group on the 7th and 14th day of stress(P<0.05).Compared with the control group,the Sobs index,Chao index,ACE index and Shannon index of the model group were decreased(P<0.05).The number of unique species abundance(OTU)in the control group was 130,and 91 in the model group.The relative abundance of female Firmicutes in the control group(64.87%)was higher than that in the model group,and the relative abundance of Bacteroides(31.72%)was lower than that of the model group(46.35%).The Sobs index,Chao index,ACE index,Simpson index and Shannon index of the control offspring group were higher than those of the model offspring group(P<0.05).The number of unique OTUs in the model offspring group was 75,and 93 in the control offspring group.The relative abundance of Firmicutes(60.24%)in the control offspring group was higher than that of the model offspring group(52.95%).Conclusion Chronic stress during pregnancy can not only lead to the disorder of intestinal flora in female rats,but also lead to the change of intrauterine environment,thus affecting the diversity of intestinal flora in offspring.