Figure 1

Experimental protocols for the mouse model of chronic micro-inflammation and absence of inflammation. A) Colitis was induced by intrarectal administration of 100 mg/Kg of DNBS in solution in 30% ethanol (EtOH). Control mice (without colitis) received only 30% EtOH. The effects of DNBS are highest during the first 3 days after its administration (DNBS period). Ten days after the end of the DNBS period, bacterial culture, PBS, or supernatant (SN) were intragastrically administered daily for 10 days (gavage period). Colitis was reactivated 21 days after the first DNBS injection with a second injection of 50 mg/Kg of DNBS solution. Three days after reactivation mice were sacrificed. The severity of the reactivated colitis was assessed from difference in body weight (B), macroscopic score (C), MPO activity (D), histological score (E) (n = 16 mice per group) and lipocalin-2 levels (F) (n = 2*4 = 8 mice per group) between control non-inflamed (EtOH-PBS), control inflamed (DNBS-PBS), bacteria-free culture medium (DNBS-LYBHI), F. prausnitzii strain A2-165 (DNBS-Fprau), and F. prausnitzii A2-165 SN (DNBS-SN) groups. Experiments were performed at least in duplicate. Normal appearance of the colon of a control mouse with no inflammation (G) and of a mouse with micro-inflammation (H).