Rubel Md Zahir Uddin, Masum Md Abdul, Namba Takashi, Hiraishi Masaya, Kon Yasuhiro, Ichii Osamu
Laboratory of Anatomy, Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan.
Department of Poultry Science, Faculty of Animal Science and Veterinary Medicine, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh.
Histol Histopathol. 2025 Aug;40(8):1195-1208. doi: 10.14670/HH-18-865. Epub 2024 Dec 26.
Sex hormones regulate gut function and mucosal immunity; however, their specific effects on the mucosa-associated lymphoid tissue (MALT) in the rectum of mammals remain unclear. Here, we aimed to investigate the influence of sex on MALT in the rectum of mammals by focusing on the rectal mucosa-associated lymphoid tissues (RMALTs) of C57BL/6NCrSIc mice. Histological analysis revealed that RMALTs were predominantly located in the lamina propria and submucosa of the rectal mucosa, with a significant sex-related difference in the distance from the anorectal junction to the first appearance of the RMALT. Despite similar RMALT numbers, females exhibited significantly larger RMALTs than males. Immunostaining revealed the presence of various immune cells, including T cells, B cells, macrophages, proliferative immune cells, lymphatic vessels, and high endothelial venules (HEVs), in RMALTs. Compared with males, females showed elevated T cell, helper T cell, and cytotoxic T-cell gene expression levels, along with high percentages of specific T-cell subsets. The factors influencing RMALT development, such as the presence of HEVs, C-X-C motif chemokine ligand 13 expression, and RMALT-containing cell proliferation, were also explored. Overall, this study revealed the detailed attributes of RMALTs, their immune cell composition, and their determinants in male and female mice, providing insights into the sex-specific characteristics of the rectal mucosal immune system.
性激素调节肠道功能和黏膜免疫；然而，它们对哺乳动物直肠黏膜相关淋巴组织（MALT）的具体影响仍不清楚。在此，我们旨在通过关注C57BL/6NCrSIc小鼠的直肠黏膜相关淋巴组织（RMALT）来研究性别对哺乳动物直肠MALT的影响。组织学分析显示，RMALT主要位于直肠黏膜的固有层和黏膜下层，从肛门直肠交界处到RMALT首次出现的距离存在显著的性别差异。尽管RMALT数量相似，但雌性的RMALT明显大于雄性。免疫染色显示RMALT中存在各种免疫细胞，包括T细胞、B细胞、巨噬细胞、增殖性免疫细胞、淋巴管和高内皮微静脉（HEV）。与雄性相比，雌性的T细胞、辅助性T细胞和细胞毒性T细胞基因表达水平升高，以及特定T细胞亚群的百分比更高。还探讨了影响RMALT发育的因素，如HEV的存在、C-X-C基序趋化因子配体13的表达以及含RMALT细胞的增殖。总体而言，本研究揭示了RMALT的详细特征、其免疫细胞组成以及雄性和雌性小鼠中的决定因素，为直肠黏膜免疫系统的性别特异性特征提供了见解。
