CNP signal pathway up-regulated in rectum of depressed rats and the interventional effect of Xiaoyaosan

Figure 3 Immunohistochemical analysis of C-type natriuretic peptide in rat rectum. A: C-type natriuretic peptide (CNP) expression in rectum smooth muscle layer of rats (arrows); B: CNP expression in rectum mucosal/serosal layers of rats (arrows); C: Staining index of CNP expression in the rectum of the five groups. Data are presented as mean ± SE. Arrows denote areas of positivity. N: Primary control group M: Depression model group; D: Low dose Xiaoyaosan (XYS) group; Z: Middle dose XYS group; G: High dose XYS group. The difference between the depression model group and the primary control group was significant (n = 9; ^bP < 0.01 vs M). The high and middle XYS dose groups were significantly different compared with the depression model group (n = 9; ^bP < 0.01 vs M). Scale bar = 50 μm.