Fig. 4.

Alterations of tight junction protein expression in the colon of mice subjected to circadian rhythm disruption. The expression of tight junction molecules was measured in the intestinal epithelial cell-enriched fractions of the colon of mice exposed to 12-h light/dark cycling (LD) or constant 24-h light (LL) for 4 weeks. A mRNA expression of ZO-1, occludin, and tricellulin as analyzed by real-time PCR. B–D Protein expression levels from the same mice as (A). Protein expression of ZO-1, occludin and tricellulin was assessed by immunoblotting (B) and band intensity was quantified by densitometric analysis using Image J program (C). p indicates the level of statistical significance in the LL group compared to the LD group for individual genes and proteins. Values are mean ± SEM; n = 4–5