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Regional heterogeneity in immunoreactive macrophages/microglia in the rat pineal gland
Author(s) -
JiangShieh Ya Fen,
Wu Ching Hsiang,
Chang Min Lin,
Shieh Jeng Yung,
Wen Chen Yuan
Publication year - 2003
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1034/j.1600-079x.2003.00054.x
Subject(s) - microglia , immunolabeling , pineal gland , biology , antigen , population , cell type , immunohistochemistry , antibody , immunocytochemistry , microbiology and biotechnology , macrophage , pinealocyte , cytoplasm , pathology , cell , immunology , endocrinology , melatonin , medicine , inflammation , biochemistry , in vitro , environmental health
Using specific macrophage antibodies (OX‐42, OX‐6, ED‐1 and ED‐2), this study examined the distribution of macrophages/microglia in the pineal gland of adult rats. Except for ED‐2, all antibodies labeled distinct subpopulations of macrophages/microglia in the gland; ED‐2 labeling was hardly detectable. The quantitative study showed that the pineal macrophages/microglia (PMM) expressing complement type 3 receptors (OX‐42) were more numerous than those expressing the major histocompatibility complex class II antigen (OX‐6) or unknown cytoplasmic/lysosomal antigens (ED‐1). The PMM were ubiquitous, especially the OX‐42 labeled cells which were distributed from the dorsal to the ventral aspect of the gland. The macrophages/microglia labeled with OX‐6 or ED‐1 were localized mainly in the intermediate portion of the pineal gland. Immunolabeled cells were sparsely distributed in the distal portion of the pineal gland. A notable feature was that the OX‐6 labeled macrophages/microglia showed a proximal–distal gradient in cell density. Another interesting feature was the occurrence of prominent cell aggregations around the larger blood vessels. These cells were mostly round and exhibited different immunoreactivity. Confocal microscopic study with triple immunolabeling further revealed that individual PMM cell possessed two or more different antigens (ED‐1 + /OX‐6 + , OX‐42 + /OX‐6 + or OX‐42 + /ED‐1 + ). Remarkably, a large population co‐expressed ED‐1 + /OX‐6 + /OX‐42 + . The present results show that the expression of immunoreactive molecules in PMM varies in topographical distribution of the cells. It is suggested that this may be linked to their immunoregulatory functions in the gland.