Butyrate upregulates the expression of tight junctional proteins in rat lung microvascular endothelial cells. (A): Western blot analysis of tight junctional proteins, Ac-tubulin, and Ac-H3 in RMVEC. Growth-arrested cells (48 h, DMEM without serum) remained untreated or stimulated with butyrate (0.1, 1, and 10 mM) for 24 h. Total cell lysates (20–30 μg) were subjected to Western blot analysis (B): Densitometric analysis of Western blot data show the relative intensity of protein expression in butyrate-stimulated cell versus without treatment; data represent a mean +/− SED from three to four independent experiments; * p < 0.05; ** p < 0.01.