Effects of local TGF-β1 levels and dexamethasone treatment on colon tissue apoptosis in TNBS-treated mice. AdTGF-β1 was delivered to the colons of TNBS mice and dexamethasone (5 mg/kg body weight) was given once a day by orogastric gavage for 4 days. Total protein was extracted from colonic tissues using radioimmunoprecipitation assay lysis buffer. Expression of (A) the apoptotic proteins caspase3 and Bim as well as (B) p38MAPK/JNK/c-Jun pathway activity were assessed using western blot analysis. Doses: AdTGF-1, 1×107 pfu; AdTGF-2, 1×108 pfu; AdTGF-3, 1×109 pfu. Values are expressed as the mean ± standard deviation (n=4 per group). *P<0.05 vs. CTL; #P<0.05 vs. TNBS; &P<0.05 vs. TNBS + AdTGF-1; $P<0.05 vs. TNBS + AdTGF-2. CTL, control; TNBS, 2,4,6-trinitrobenzenesulfonic acid; AdTGF, adenovirus overexpressing transforming growth factor β1; Dex, dexamethasone; MAPK, mitogen-activated protein kinase; JNK, c-Jun N-terminal kinase; SD, standard deviation.