Morphology of WT and CF small intestine without and with lubiprostone treatment. Mice were treated with lubiprostone (10 μg/kg-day) for two weeks, as indicated. After an overnight fast, the small intestine was fixed in Carnoy's solution and processed for PAS/AB staining. The CF intestine has much greater mucus in the crypts as well as along the villus surfaces, as compared to WT tissue. There was not an obvious effect of lubiprostone on mucus in either WT or CF mice as compared to controls.