Loss of HYAL2 in hematopoietic cells exacerbates DSS-induced colitis. Bone marrow transplant (BMT) chimeras were generated by using WT (HYAL2^+/+) and KO (HYAL2^−/−) mice as host and BM donor, respectively. (A) Cross-sections of distal colon collected from mice after 7 days of 2.5% DSS. Hematoxylin-eosin staining reveals the cellular and structural changes in the intestine, including inflammatory leukocyte infiltration. Boxed regions are enlarged in adjacent panels. Scale bars indicate 500 μm. L denotes the intestinal lumen, triangles indicate the epithelial layer, S denotes the submucosa, and arrows indicate the muscularis mucosae. (B) Body weight was measured on day 7 and compared with starting weight. (C) Mice were scored for outward signs of disease, including weight loss, hunched posture, ruffled fur, bloody stools, and rectal prolapse. (D) Distal colon sections from mice after 7 days of DSS were scored for pathologic changes, including erosion of the epithelial layer, leukocyte infiltration, submucosal swelling, muscularis mucosae hyperplasia, and increased vascularization. (E) Colons from mice euthanized after 7 days of DSS were measured for distance (centimeters) from the distal end of the cecum to the rectum. Symbols indicate genotypes and treatment: (▲) WT mice receiving WT BM, n = 8; and (○) WT mice receiving HYAL2 KO BM, n = 7. Data are reported as mean ± SEM. *P < .05.