Fig. 3.

The effect of PCA on the expression of tight junction proteins. The mRNA expression of ZO-1 (a), occludin (b), and claudin-1 (c) was quantitated by real-time PCR, and the protein expression of ZO-1 (d), occludin (e), and claudin-1 (f) was detected by immunohistochemical staining. In real-time PCR, the data were shown as means ± SD (n = 6) of mRNA relative expressions. In immunohistochemical staining, the pictures shown were the representative of 6 individual stained sections photographed at 100× magnification, and tight junction proteins were stained yellow or brown-yellow. CTL, a basal diet; AUR, a basal diet containing 50 mg/kg aureomycin; PCA, a basal diet supplemented with 0.4% protocatechuic acid. *P < 0.05 compared with CTL, ^#P < 0.05 compared with AUR