孕期应激致子代粪便肠道菌群及靶向代谢组水平的改变

Changes of Fecal Intestinal Flora and Targeted Metabolome in Offspring Induced by Stress During Pregnancy

目的 观察大鼠孕期应激致仔鼠肠道菌群及靶向代谢物的变化,探索子代肠道菌群与短链脂肪酸的联系。方法 选择孕期21 d慢性不可预知温和应激建立动物模型,采用放射免疫法测量雌鼠血浆皮质醇质量浓度;收集仔鼠产后20 d粪便,利用16S r RNA高通量测序和靶向代谢组学方法测定仔鼠肠道菌群结构及短链脂肪酸含量。结果 孕期应激导致模型组母鼠的血浆皮质酮在第7天、14天高于对照组母鼠(P<0.05)。孕期慢性不可预知应激致子代的肠道菌群结构发生改变,包括物种丰度减少,物种多样性降低,物种组成改变。孕期应激还使短链脂肪酸代谢量发生变化,模型组乙酸、丙酸、丁酸的代谢量均升高(P均<0.05);肠道菌群与短链脂肪酸也有一定的关联性,乙酸、丙酸和丁酸对肠道菌群的影响较大;Phascolarctobacterium与丁酸、异戊酸均呈负相关(P均<0.05);梭菌属_sensu_stricto_1与丙酸、丁酸、异戊酸均呈正相关(P均<0.01);普雷沃氏菌属_NK3B31_group与乙酸、丁酸、戊酸、异戊酸均呈正相关(P均<0.05);双歧杆菌(Bifidobacterium)与丙酸呈正相关(P<0.05)。结论 孕期应激对子代肠道菌群的物种组成及物种多样性产生影响,从而改变短链脂肪酸的代谢水平。

Objective To observe the changes of intestinal microflora and targeted metabolites in offspring rats induced by pregnancy stress,and to explore the relationship between intestinal microflora and short-chain fatty acids in offspring. Methods Chronic unpredictable mild stress at 21 days gestation was selected to establish animal model. The plasma cortisol concentration of female rats was measured by radioimmunoassay. Feces were collected 20 days after delivery. The intestinal microflora structure and the content of short-chain fatty acids were determined by 16S rRNA high-throughput sequencing and targeted metabolomics. Results The plasma level of corticosterone in model group was significantly higher than that in control group on day 7 and 14 due to pregnancy stress(P<0.05). Chronic unpredictable stress during pregnancy led to changes in the structure of intestinal flora in the offspring of the model group,including decreased species abundance,decreased species diversity and altered species composition. Pregnancy stress also changed the metabolism of short-chain fatty acid,and the metabolism of acetic acid,propionic acid and butyric acid in model group increased(P all<0.05).There was also a certain correlation between intestinal flora and short-chain fatty acids. It was found that acetic acid,propionic acid and butyric acid had a greater influence on intestinal flora. Phascolarctobacterium was negatively correlated with butyric acid and iso-valerate(P all<0.05). There was a positive correlation between clostridium_sensu_stricto_1 and propionic acid,butyric acid and iso-valeric acid(P all<0.01). Prevotella_NK3B31_group was positively correlated with acetic acid,butyric acid,valerate and iso-valerate(P all<0.05).Bifidobacterium was positively correlated with propionic acid(P<0.05). Conclusion Stress during pregnancy can affect the species composition and diversity of intestinal flora of offspring,thus changing the metabolism level of short-chain fatty acids.