[Improvement effect of Lycium barbarum polysaccharide on the intestinal flora of pregnant rats and their offspring under chronic stress].

Objective: To understand the improvement effect of Lycium barbarum polysaccharide (LBP) on the intestinal flora of mother mice during pregnancy and their offspring who experienced chronic stress, and provide new ideas for improving the effect of stress on the intestinal tract. Methods: From July to October 2019, 24 SPF-grade female SD rats were selected and divided into control group, stress group, and stress+LBP group, with 8 rats in each group. A chronic unpredictable mild stimulation model during pregnancy was established (21 days) , and 40 mg/kg LBP solution was administered by gavage on the 8th day of stress. Venous blood from the medial canthus of the female mice was collected on the 1st day before stress and on the 1st, 7th, 14th and 21st days, respectively. Cortisol was measured and corticosterone concentration was calculated. The fresh feces of famale mice after stress and 20-day postnatal offspring mice were collected, and Illumina Miseq sequencing technology, alpha diversity and community composition were used to analyze the diversity and structure of intestinal flora. Results: On the 7th and 14th days of stress, the plasma corticosterone concentration of female mice in the stress group and stress+LBP group was higher than that in the control group (P<0.05) . In the Alpha diversity of female mice, the Ace index of the stress group was lower than that of the control group (P<0.05) . The analysis of intestinal flora structure showed that at the species level, the proportions of Lachnospiraceae and Lactobacillus in the stress+LBP group were higher than those in the stress group and control group. At the order level, the proportion of Clostridiales in the stress+LBP group was higher than that in the stress group and lower than that in the control group, while the proportion of Lactobacillales was higher than that in the stress group and control group. In the Alpha diversity of the offspring group, the Shannon index, Ace index and Chao index of the stress+LBP offspring group were higher than those of the stress offspring group (P<0.05) . The proportion of Lactobacillus in the stress+LBP offspring group was higher than that in the control offspring group and stress offspring group, and the proportions of Lachnospiraceae and Ruminococcaceae in the stress+LBP offspring group were higher than those in the stress offspring group, the proportion of Bacteroidales in the stress+LBP offspring group was lower than that in the stress offspring group, and the proportion of Clostridiales in the stress+LBP offspring group was higher than that in the stress and control offspring groups. Conclusion: The intervention of LBP may improve the changes in the intestinal flora diversity, abundance and flora structure of mother mice and offspring caused by pregnancy stress, thereby maintaining the balance of intestinal flora.目的： 了解枸杞多糖（LBP）对经历孕期慢性应激的母鼠及其子代肠道菌群的改善作用，为改善应激对肠道的影响提供新思路。 方法： 于2019年7至10月，选择24只SPF级雌性SD成年大鼠，分为对照组、应激组、应激+LBP组，每组8只。建立孕期慢性不可预知温和刺激模型（21 d），并于应激第8天行40 mg/kg LBP溶液灌胃干预。分别在应激前1天和第1、7、14、21天取母鼠内眦静脉血，测定皮质醇并计算皮质酮浓度。收集应激结束后母鼠和出生后20 d子鼠的新鲜粪便，运用Illumina Miseq测序技术、Alpha多样性、群落组成等分析肠道菌群的多样性与结构变化。 结果： 在应激第7、14天，应激组和应激+LBP组母鼠血浆皮质酮浓度水平高于对照组（P<0.05）。母鼠Alpha多样性中应激组Ace指数低于对照组（P<0.05）；肠道菌群结构分析显示，在种水平下，应激+LBP组毛螺菌科、乳杆菌占比高于应激组和对照组；在目水平下，应激+LBP组梭菌目占比高于应激组、低于对照组，而乳杆菌目占比高于应激组和对照组。子鼠组Alpha多样性中应激+LBP子鼠组Shannon指数、Ace指数和Chao指数均高于应激子鼠组（P<0.05）；肠道菌群结构在种水平下，应激+LBP子鼠组乳杆菌占比高于对照子鼠组和应激子鼠组，应激+LBP子鼠组毛螺菌科和瘤胃菌科占比高于应激子鼠组；在目水平下，应激+LBP子鼠组拟杆菌目占比低于应激子鼠组，应激+LBP子鼠组梭菌目占比高于应激子鼠组和对照子鼠组。 结论： LBP的干预可能改善孕期应激对母鼠及子代肠道菌群多样性、丰富度和菌群结构的改变，从而维持肠道菌群的平衡。.