Induction of IL-8, MCP-1, and bFGF by TNF-alpha in retinal glial cells: implications for retinal neovascularization during post-ischemic inflammation.
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.
Yoshida
Shigeo
S
Department of Ophthalmology, Kyushu University Graduate School of Medicine, 3-1-1 Maidashi, 812-8582 Fukuoka, Japan. yosida@med.kyushu-u.ac.jp
Yoshida
Ayako
A
Ishibashi
Tatsuro
T
D000818:Animals; D015152:Blotting, Northern; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D016222:Fibroblast Growth Factor 2 / Q000096:biosynthesis* / Q000235:genetics; D019084:Fluorescent Antibody Technique, Indirect; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D008262:Macrophage Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000187:drug effects* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D015861:Retinal Neovascularization / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*
D018932:Chemokine CCL2; D016209:Interleukin-8; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D016222:Fibroblast Growth Factor 2