Elmore Susan A
Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences/NIH, 111 Alexander Drive, Research Triangle Park, NC 27709, USA.
Toxicol Pathol. 2006;34(5):656-65. doi: 10.1080/01926230600865556.
The thymus is a primary or central lymphoid organ in which T lymphocytes undergo differentiation and maturation autonomously within the cortex, without the need for antigenic stimulation, and it is essential for the normal development and function of the immune system. The thymus has been shown to be a sensitive target organ following exposure to immunotoxicants and endogenous corticosteroids, and a decrease in size or weight is often one of the first noted measures of compound-induced effects with cortical lymphocytes (thymocytes) being especially susceptible. Therefore, changes in thymus histopathology and architecture are considered to be of particular relevance for immunotoxicity screening. The separate compartments in each lymphoid organ should be evaluated separately and descriptive rather than interpretive terminology should be used to characterize changes within those compartments (Haley et al., 2005). Therefore, enhanced histopathological evaluation of the thymus involves the determination of the size and cellularity of the cortex and medulla, which should be noted separately. Other changes to evaluate include, but are not limited to, increased lymphocyte apoptosis, lymphocyte necrosis, cortex:medulla ratio and an increase or decrease in the epithelial component of the thymus.
胸腺是一个主要的或中枢淋巴器官，T淋巴细胞在皮质内自主进行分化和成熟，无需抗原刺激，它对免疫系统的正常发育和功能至关重要。胸腺已被证明是暴露于免疫毒素和内源性皮质类固醇后一个敏感的靶器官，其大小或重量的减少通常是化合物诱导效应的最早观察指标之一，其中皮质淋巴细胞（胸腺细胞）尤为敏感。因此，胸腺组织病理学和结构的变化被认为与免疫毒性筛选特别相关。每个淋巴器官的不同区域应分别进行评估，并且应用描述性而非解释性术语来描述这些区域内的变化（Haley等人，2005年）。因此，对胸腺进行强化组织病理学评估包括确定皮质和髓质的大小和细胞数量，应分别记录。其他需要评估的变化包括但不限于淋巴细胞凋亡增加、淋巴细胞坏死、皮质与髓质比例以及胸腺上皮成分的增加或减少。
