Small intestinal apoptosis and increased endotoxin-induced mortality associated with elevated TNF production in IKKβ(EE)^IEC mice. (a) Rectal temperature and survival of WT (gray diamonds) and IKKβ(EE)^IEC (black squares) mice after LPS (5 mg/kg E. coli O111:B4) injection. Results are means ± SEM (n = 8). *, P < 0.05 versus WT. Data are pooled from three independent experiments. (b) Abdomens of WT and IKKβ(EE)^IEC mice 4 h after LPS (1 mg/kg) injection. Arrow points at fluid-filled dilated small bowel in Tg mice. Jejunal sections were stained with either H&E (top) or by an in situ TUNEL assay (bottom). Representative of 10 experiments. (c) Circulating TNF and IL-1β after LPS administration. Results are means ± SEM (n = 4). *, P < 0.05 versus WT. Data are representative of three independent experiments. (d) Intestinal histology of IKKβ(EE)^IEC x tnfa^−/− and IKKβ(EE)^IEC x tnfrsf1a^−/− mice. Jejunal sections were H&E stained. Representative of five experiments. (e) The indicated mouse strains were analyzed 4 h after LPS injection with or without an accompanying dose of Enbrel (sTNFRII) as indicated. Small intestinal sections were stained with H&E. Representative of three experiments. (f) Rectal temperature and survival of WT (gray diamond), IKKβ(EE)^IEC (black square), IKKβ(EE)^IEC x tnfsrf1^−/− (black circle), IKKβ(EE)^IEC x tnf^−/− (gray triangle), IKKβ(EE)^IEC + sTNFRII (black triangle) mice after LPS injection. Results are means ± SEM (n = 3). Survival of WT, IKKβ(EE)^IEC x tnfsrf1^−/− (black circle), IKKβ(EE)^IEC x tnf^−/− (gray triangle), and IKKβ(EE)^IEC + sTNFRII (black triangle) is 100%. *, P < 0.05 versus IKKβ(EE)^IEC. Data are representative of three independent experiments.