Fig. 6From: Protective effect of L-pipecolic acid on constipation in C57BL/6 mice based on gut microbiome and serum metabolomicThe levels of 5-HT in serum and colonic tissues. Serum levels of 5-HT in these group(A). Representative immunohistochemical staining images in colonic tissues showing 5-HT (200x magnification, Bars 100 μm). Quantification using the ImageJ software for each group (B). Data represent the mean ± SD (n = 6)Back to article page