Differential expression of inflammatory mediators in rat microglia cultured from different brain regions

Brain Res Mol Brain Res. 1999 Mar 5;65(2):198-205. doi: 10.1016/s0169-328x(99)00016-9.


Microglial cells show a rather uniform distribution of cell numbers throughout the brain with only minor prevalences in some brain regions. Their in situ morphologies, however, may vary markedly from elongated forms observed in apposition with neuronal fibers to spherical cell bodies with sometimes extremely elaborated branching. This heterogeneity gave rise to the hypothesis that these cells are differentially conditioned by their microenvironment and, therefore, also display specific patterns of differential gene expression. In this study, microglia were isolated from 2-4 week-old mixed CNS cultures that had been prepared from neonatal rat diencephalon, tegmentum, hippocampus, cerebellum and cerebral cortex, and were investigated 24 h later. Messenger RNA levels of proteins involved in crucial immune functions of this cell type (TNF-alpha, CD4, Fcgamma receptor II, and IL-3 receptor beta-subunit) have been determined by semi-quantitative RT-PCR. The results clearly show, that three of these mRNAs (TNF-alpha, CD4, Fcgamma receptor II) are differentially expressed in microglia with hippocampal microglia displaying the highest levels of these mRNAs. The data strongly support the notion that the status of microglial gene expression depends on their localization in brain and on specific interactions with other neural cell types. Consequently, it is hypothesized that their responsiveness to signals arising in injury or disease may vary from one brain region to another.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / cytology*
  • Brain / immunology*
  • Brain Chemistry / immunology
  • CD4 Antigens / genetics
  • Cells, Cultured
  • Cerebellum / chemistry
  • Cerebellum / cytology
  • Cerebellum / immunology
  • Cerebral Cortex / chemistry
  • Cerebral Cortex / cytology
  • Cerebral Cortex / immunology
  • DNA Primers
  • Diencephalon / chemistry
  • Diencephalon / cytology
  • Diencephalon / immunology
  • Gene Expression / immunology
  • Hippocampus / chemistry
  • Hippocampus / cytology
  • Hippocampus / immunology
  • Inflammation Mediators / immunology
  • Inflammation Mediators / metabolism*
  • Microglia / cytology
  • Microglia / immunology*
  • RNA, Messenger / analysis
  • Rats
  • Rats, Wistar
  • Receptors, IgG / genetics
  • Receptors, Interleukin-3 / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tegmentum Mesencephali / chemistry
  • Tegmentum Mesencephali / cytology
  • Tegmentum Mesencephali / immunology
  • Tumor Necrosis Factor-alpha / genetics


  • CD4 Antigens
  • DNA Primers
  • Inflammation Mediators
  • RNA, Messenger
  • Receptors, IgG
  • Receptors, Interleukin-3
  • Tumor Necrosis Factor-alpha