动物造模 z-bio 2022-03-02 333

　　Objective: To investigate the effect of dexamethasone pollution in water environment on intestinal flora of mice.

　　Methods: Twenty Balb/c mice were randomly divided into control group and experimental group, with 5 mice in each group. The experimental low-dose group was fed drinking water containing 0.035 ng of dexamethasone sodium phosphate, the middle-dose group was 0.225 ng, the high-dose group was 2.25 ng, and the control group was fed drinking water without dexamethasone sodium phosphate. Changes in behavior, fur, and stool of mice were observed daily. On the 36th day, the mice were sacrificed, and the blind tissue was retrieved to extract bacterial genomic DNA. The 16S rDNA V6 variable region was amplified, and the amplified products were analyzed after denaturing gel gradient electrophoresis (DGGE). The dominant bands on the DGGE map were excised, cloned and sequenced after amplification and purification, and their sequences were compared and analyzed by BLAST.

　　RESULTS: The mice in each experimental group showed signs of irritability, fighting and biting off their tails. Cluster analysis of DGGE atlas showed that all groups of mice had relatively stable flora in the ileocecal region; principal component analysis showed that there were certain differences in the dominant flora of each group; flora diversity analysis showed that compared with the control group, low-dose The type and quantity of microflora in the group increased significantly (P<0.05); the type and quantity of the medium and high dose groups increased significantly (P<0.01). Sequence analysis of 16S rDNA V6 region showed that the experimental group and the control group had 15 common bacterial genera and 2 differential bacterial genera, and the dominant bacterial species and proportions changed. The control group was colonized with bacteria of the genus Lactobacillus, while the bacteria of the genus Lactobacillus disappeared in the medium and high dose experimental groups, but the bacteria of the genus Shigella appeared.

　　Conclusion: Dexamethasone pollution in drinking water can affect the nervous system of mice, change the type, quantity and proportion of dominant bacteria in the intestinal tract of mice, and increase the diversity of flora; inhibiting the colonization of intestinal probiotics is beneficial to the intestinal Invasion of pathogenic bacteria.