Comparative Analysis of Host Immune Responses in Colonic Tissue Samples of Patients and Experimentally Induced BALB/c Mice with Ulcerative Colitis

Background: Ulcerative colitis is a chronic immune-mediated inflammatory disease characterized by widespread inflammation in the colon's mucosal layer. Experimentally induced models in animals aid in describing the immunopathogenesis and help discover novel therapeutic approaches. Objectives: This study aimed to investigate the histopathological alterations, immune response, and apoptosis in the colonic tissues of patients and mice with experimentally induced colitis. Methodology: Colonic tissues from ulcerative colitis patients were collected following surgical operations. Dextran sulfate sodium (DSS) was administered to induce colitis in BALB/c mice. Both colonic tissue samples of humans and mice were processed for histopathological investigation. Additionally, immunohistochemistry was performed to characterize CD3, CD20, CD68, and caspase-3 tissue markers. Results: DSS-induced colitis affected both sexes of mice, with males exhibiting more severe symptoms. Numerous histopathological alterations were detected in the colonic tissues of patients and induced mice compared to control mice, including surface ulceration and erosion, cryptitis, crypt distortion, and various inflammatory cell infiltrations. Moreover, abscesses were detected in the human colonic tissue. The immunohistochemical study revealed that CD3 was the most abundant inflammatory cell in the colonic tissues of patients and mice, followed by CD20 (B cells) and CD68 (macrophages). Caspase-3 expression was identified in all samples, revealing diverse levels, and was particularly prominent in mice, which recorded a high score. Conclusion: The remarkable inflammatory reactions documented in the colon tissue by the current study confirm the importance of understanding the inflammatory responses responsible for ulcerative colitis.