Anti-inflammatory properties of butyrate-producing atypical Escherichia coli in a murine colitis model.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 1 ing a 2-plasmid system capable of introducing foreign genes and overexpressing genes for gene expression in the butyric acid metabolic cycle (Supplementary Fig. 1, Supplementary Table 1). Animals were randomly divided into 4 groups; control+phosphate buffered saline (PBS) (n = 3), dextran sulfate sodium (DSS)+PBS (n = 4), DSS+atEc (n = 4), and DSS+butyrate atEc groups (n = 4). Male C57BL/6 mice (8-week-old) were treated with 1 × 10 bacteria in 0.2 mL PBS daily by oral gavage before and after the induction of DSS colitis (from day 0 to day 12) (Fig. 1A). DSS (2.5% [w/v]; MP Biomedicals, Solon, OH, USA) was added to their drinking water from day 3 of gavage and continued for day 9, and water was changed to DSS-free water before euthanization. All mice were sacrificed 12 days after the onset of the study. Mice were monitored for survival, body weight loss, disease activity index, and colon length. Parts of the distal colon were cut into 2 to 3 pieces for periodic acid-Schiff staining and histologic scoring was obtained. All animal testing complied with all applicable Korean laws and was approved by the Institutional Animal Care and Use Committee of Yonsei University Severance Hospital (Seoul, Korea) (IACUC No. 2019-0241). The experiments complied with the approved IACUC guidelines. All results are expressed as standard error of the mean. GraphPad Software (La Jolla, CA, USA) was used for all analyses. The significance of differences between conditions was assessed using one-way or two-way analysis of variance followed by Holm-Sidak or Tukey’s multiple comparison test, respectively. pISSN 1598-9100 • eISSN 2288-1956 https://doi.org/10.5217/ir.2022.00112 Intest Res, Published online November 14, 2022