Dextran sulfate sodium salt corrupted colonic crypts declined the smooth muscle tension in mouse large intestine

Abstract

Ulcerative colitis is one kind of colonic mucosa damage, shows high number of inflammatory epithelial cells. Dextran sulfate sodium salt (DSS) induce a milder onset of colitis or a more aggressive response. It may damage the protective effects on intestinal barrier. In this study, we investigated the damaging of colon crypts, evaluated the smooth muscle tension beneath corrupted crypts in DSS exposed mice. Methodsfemale specific-pathogen-free BALB/C mice (n=16) are randomly divided as: group A: control mice (n=4); group B: DSS-mice (colitis, 5% DSS in drink water, days 1 to 7, n = 12). The DSS is replaced every 2 days. On day 8, mice colons are excised from the colon-cecal junction to the anus. The distal colon segment is longitude incision and aberrant crypt area are determined by methylene blue staining method. The smooth muscle strip is separated and prepared for passive tension tests. The rest segment is fixed with 10% formalin and embedded in paraffin. Histological scores are evaluated in hematoxylin-eosin staining section: crypt damage (none = 0, basal 1/3 damaged = 1, basal 2/3 damaged = 2, only the surface epithelium is intact = 3, and entire crypt and epithelium are lost = 4). The smooth muscle passive tension beneath the aberrant crypt area in DSS-mice are tested and compared with the preparations from control mice. ResultsIn DSS uptake mice, the inflammation in large intestine mucosa damaged crypts with architectural distortions on day 7 (n=7). In crypts damage area, the smooth muscle passive tension and relative myogenic spontaneous contraction parameters are significantly reduced under the high preload conditions. The maximum rate of change of velocity of spontaneous contraction was noticeable attenuated. ConclusionOur findings demonstrate that low dosage DSS water drink result in corrupted colonic crypts. The corrupted crypts damage the large intestinal epithelium barrier, affect the smooth muscle functions, which declined in myogenic spontaneous contraction under the preload. This further may reduce the peristalsis in large intestine.