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Cytokine transcripts expressed by microglia in vitro are not expressed by ameboid microglia of the developing rat central nervous system
Author(s) -
Hurley Sean D.,
Walter Sharon A.,
SempleRowland Susan L.,
Streit Wolfgang J.
Publication year - 1999
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/(sici)1098-1136(19990201)25:3<304::aid-glia10>3.0.co;2-w
Subject(s) - microglia , biology , tumor necrosis factor alpha , neuroglia , central nervous system , cytokine , in vivo , neuroscience , immunology , macrophage , in vitro , microbiology and biotechnology , inflammation , genetics
Because of morphological similarities between ameboid microglia in the developing central nervous system (CNS), brain macrophages in the injured CNS, and cultured microglia in vitro, it is thought that these cell types are functionally equivalent. To investigate the validity of this assumption, we have compared mRNA levels of interleukin‐1α and ‐1β (IL‐1α and IL‐1β), tumor necrosis factor‐α and ‐β (TNF‐α and TNF‐β), transforming growth factor‐β1 (TGF‐β1), and macrophage colony‐stimulating factor (M‐CSF) in the postnatal day 4 (P4) supraventricular corpus callosum (SVCC) with those in unstimulated cultured microglia. Control tissues included spleen, cortex, hippocampus, and cerebellum. Our analyses have shown that while IL‐1α, IL‐1β, TNF‐α, TNF‐β, and TGF‐β1 transcripts are abundantly expressed by cultured microglia, they are very low to virtually undetectable in the SVCC. These data strongly suggest that ameboid microglia, which are concentrated in the SVCC, are unlikely to be a significant source of these cytokines. Our study, which shows clear differences in the functional status of cultured microglia vs. ameboid microglia in vivo, stresses the importance of using caution when interpreting in vitro findings in terms of the in vivo functions of microglia. GLIA 25:304–309, 1999. © 1999 Wiley‐Liss, Inc.