Induction of IL-8, MCP-1, and bFGF by TNF-alpha in retinal glial cells: implications for retinal neovascularization during post-ischemic inflammation

Graefes Arch Clin Exp Ophthalmol. 2004 May;242(5):409-13. doi: 10.1007/s00417-004-0874-2. Epub 2004 Mar 17.

Abstract

Background: We have demonstrated that macrophages/microglia were activated during post-ischemic inflammation in a mouse model of ischemic retinal neovascularization, and that the angiogenesis induced by tumor necrosis factor-alpha (TNF-alpha) appeared to be modulated through such angiogenic factors as interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) in microvascular endothelial cells. We have extended these studies, and investigated whether TNF-alpha is localized in macrophages/microglia in the mouse model of retinal neovascularization, and whether TNF-alpha can induce angiogenic factors in retinal glial cells.

Methods: C57BL/6 J pups were placed in a 75% oxygen environment on postnatal day 7 (P7) for 5 days and then returned to room air. The co-localization of TNF-alpha with macrophages/microglia in the ischemic retina was examined by fluorescent immunohistochemistry. Bovine retinal glial cells were isolated for Northern blot analysis to quantify the expression levels of monocyte chemotactic protein-1 (MCP-1), IL-8, bFGF, and VEGF.

Results: Double staining of retinas revealed that the TNF-alpha expression level was enhanced in macrophages/microglia 4 days after the hypoxia. Cellular mRNA levels of MCP-1, IL-8, and bFGF, but not VEGF, were increased after treating retinal glial cells with TNF-alpha (100 U/ml).

Conclusions: The results indicate that TNF-alpha is produced by activated macrophages/microglia and may participate in retinal neovascularization during post-ischemic inflammation through the induction of potent angiogenic factors in an autocrine or paracrine manner.

MeSH terms

  • Animals
  • Blotting, Northern
  • Chemokine CCL2 / biosynthesis*
  • Chemokine CCL2 / genetics
  • Fibroblast Growth Factor 2 / biosynthesis*
  • Fibroblast Growth Factor 2 / genetics
  • Fluorescent Antibody Technique, Indirect
  • Interleukin-8 / biosynthesis*
  • Interleukin-8 / genetics
  • Macrophage Activation
  • Mice
  • Mice, Inbred C57BL
  • Microglia / drug effects*
  • Microglia / metabolism
  • Polymerase Chain Reaction
  • RNA, Messenger / metabolism
  • Reperfusion Injury / metabolism
  • Retina / drug effects*
  • Retina / metabolism
  • Retinal Neovascularization / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism
  • Tumor Necrosis Factor-alpha / pharmacology*

Substances

  • Chemokine CCL2
  • Interleukin-8
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • Fibroblast Growth Factor 2