Long term effects of lipopolysaccharide on satellite glial cells in mouse dorsal root ganglia

Exp Cell Res. 2017 Jan 1;350(1):236-241. doi: 10.1016/j.yexcr.2016.11.026. Epub 2016 Nov 30.

Abstract

Lipopolysaccharide (LPS) has been used extensively to study neuroinflammation, but usually its effects were examined acutely (24h<). We have shown previously that a single intraperitoneal LPS injection activated satellite glial cells (SGCs) in mouse dorsal root ganglia (DRG) and altered several functional parameters in these cells for at least one week. Here we asked whether the LPS effects would persist for 1 month. We injected mice with a single LPS dose and tested pain behavior, assessed SGCs activation in DRG using glial fibrillary acidic protein (GFAP) immunostaining, and injected a fluorescent dye intracellularly to study intercellular coupling. Electron microscopy was used to quantitate changes in gap junctions. We found that at 30 days post-LPS the threshold to mechanical stimulation was lower than in controls. GFAP expression, as well as the magnitude of dye coupling among SGCs were greater than in controls. Electron microscopy analysis supported these results, showing a greater number of gap junctions and an abnormal growth of SGC processes. These changes were significant, but less prominent than at 7 days post-LPS. We conclude that a single LPS injection exerts long-term behavioral and cellular changes. The results are consistent with the idea that SGC activation contributes to hyperalgesia.

Keywords: Dorsal root ganglia; Gap junctions; Glial activation; Inflammation; Pain; Satellite glial cells.

MeSH terms

  • Animals
  • Behavior, Animal / drug effects
  • Ganglia, Spinal / cytology*
  • Gap Junctions / metabolism
  • Glial Fibrillary Acidic Protein / metabolism
  • Lipopolysaccharides / pharmacology*
  • Mice
  • Mice, Inbred BALB C
  • Neuroglia / cytology
  • Neuroglia / drug effects*
  • Neuroglia / metabolism
  • Neurons / drug effects
  • Neurons / metabolism
  • Satellite Cells, Perineuronal / drug effects*
  • Time

Substances

  • Glial Fibrillary Acidic Protein
  • Lipopolysaccharides