Colitis grade dss

General laboratory chemicals and reagent solutions were purchased from Sigma-Aldrich (St. Louis, MO). ELISA kits for IL-6 and TNF-α were purchased from Bio-legend. ELISA kit for CXCL1 was purchased from R&D systems. All antibodies were purchased from Santacruz unless otherwise specified. LPS was purchased from Sigma Aldrich. Colitis grade DSS (36,000–50,000 M.W) was purchased from MP Bio. UroA was custom synthesized as previously described^{23 (link)}.

Sodium hyaluronate (Mw 1.2 × 10⁶ Da) was purchased from Lifecore Biomedical, USA. Polyvinyl alcohol (Mw 13k–23k Da), 4‐(4.6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium chloride (DMTMM), PLGA (Resomer RG 504H, poly(d,l‐lactide‐co‐glycolide); 50:50, average Mw ≈ 38k–54k Da), and chitosan (average Mw ≈ 50k–190k Da) were purchased from Sigma‐Aldrich. LPS, FITC‐dextran (Mw 4k Da), Alcian blue, Nuclear Fast Red were purchased from Sigma‐Aldrich. ELISA kits for IL‐6 and TNF‐α were purchased from Bio‐legend, Multiplex ELISA pro‐inflammatory panel was purchased from Meso Scale Discovery. E‐Cadherin monoclonal antibody (Alexa Fluor 488 conjugate; eBioscience, Thermo Scientific), recombinant anti‐beta catenin antibody (Alexa Fluor 568 conjugate; ab201823), Human/Mouse CD44 antibody (Alexa Fluor 488 conjugate; R&D systems), occludin, mouse IgG1 Alexa Fluor 488, β‐actin from Santa Cruz Biotechnology, and DAPI purchased from Life Technologies. Colitis grade DSS (Mw 36k–50k Da) was from MP Bio, and other reagents used were of analytical grade.

A 0.5% solution of dextran sulfate sodium (DSS) was prepared by resuspending colitis-grade DSS (MPBio, Santa Ana, CA) in sterile drinking water and stored at 4°C. To increase permeability of the gastrointestinal epithelium, animals were treated once per day for 5-consecutive days with 200ml of the DSS-containing drinking water– administered by gavage. Animals were monitored for clinical signs of colitis and gastrointestinal distress and received palliative and clinical care at the full discretion of WNPRC veterinarians.

The single-injury protocol was adapted and modified from Oehlers et al. (2013) (link). Batches of 60 larvae were segregated into Petri dishes in 50 ml of egg water. Phenylthiourea (75 μM; Acros Organics) was added 24 h post-fertilization to prevent pigment-cell formation. To induce intestinal injury, 3 days post-fertilization (dpf) larvae were placed in freshly prepared 0.1 or 0.25% (w/v) colitis grade DSS (36,000-50,000 MW, MP Biomedical) for 3 days. In the repeated-injury protocol, larvae were treated with 0.05, 0.1 or 0.25% DSS at 5, 8 and 11 dpf for 24 h, followed by removal of DSS. Larvae were not fed for the duration of the single DSS treatment experiments (6 dpf); the larvae were fed after 7 dpf with repeated DSS. Feeding was skipped on the DSS treatment day.

Eight-week-old female C57BL/6J mice were purchased from Janvier Laboratory (Le Genest, France) and used 1 week after reception. Animals were kept in humidity- and temperature-controlled rooms under a 12 h light-dark cycle and had access to a chow diet and water ad libitum. All experiments were performed in accordance with the ethics committee “Comite d’Ethique en Experimentation Animale” (COMETHEA C2EA—45, Jouy en Josas, France). Every experiment was repeated at least two times (n = 10).
Prior to DSS administration, the mice were gavaged with a suspension of fungi: 1.10⁷ spores per gavage/mouse/day.
One week after starting the fungal administration, mice were given 2% (weight/volume) colitis grade DSS (molecular weight, 36,000–50,000; MP Biomedicals, Solon, OH, USA) dissolved in the drinking water ad libitum for 7 days, followed by a recovery period (water only) of 5 days. Animals were monitored daily for weight loss and disease activity index (DAI). The DAI is described in Table 2 and includes three parameters with a score notation from 1 to 4: weight loss, stool consistency, and presence of blood in the feces.