OS induces JNK2-dependent barrier dysfunction in mouse ileum. A: mouse ileal sheets were mounted to Ussing chambers and preincubated with or without SP, followed by administration of hyperosmotic buffer (OS). FITC-inulin transport across the tissue was measured at 1 h. Values are means ± SE (n = 5). *Values are significantly (P < 0.05) different from corresponding control values. #Value is significantly (P < 0.05) different from the value for OS group. B: ileal sheets from wild-type (WT), Jnk1−/−, and Jnk2−/− mice were mounted to Ussing chambers and incubated with (solid bars) or without (open bars) hyperosmotic buffer. FITC-inulin transport across the tissue was measured at 1-h incubation. Values are means ± SE (n = 5). *Values are significantly (P < 0.05) different from corresponding control values. C and D: ileal sheets from WT, Jnk1−/−, and Jnk2−/− mice were mounted to Ussing chambers and incubated with or without hyperosmotic buffer. C: mucosal extracts were immunoblotted for p-JNK and JNK2. D: cryosections of untreated and OS-treated tissues were stained for p-JNK. E: cryosections of untreated and OS-treated tissues were fixed and stained for F-actin using AlexFluor 488-labeled phalloidin.