Nitric oxide suppresses bFGF- and IL-1-alpha-mediated but not VEGF165-mediated angiogenesis in natively vascularized mammalian tissue.
Using the rat mesenteric window angiogenesis assay, we studied the systemic effect of the nitric oxide synthase inhibitor Nw-nitro-L-arginine methyl ester, L-NAME, on angiogenesis induced by basic fibroblast growth factor (bFGF), interleukin-1-alpha (IL-1) or vascular endothelial growth factor (VEGF165). Using technically independent morphometric and image analysis methods, the angiogenic response was quantified in variables related to (i) microvascular spatial extension and (ii) microvascular density. The test tissue, which is natively vascularized and lacks significant angiogenesis physiologically, was unaffected by surgical intervention. Two daily intraperitoneal injections of bFGF (2.20 nmole), IL-1 (1.18 nmole) and VEGF165 (480 pmole) for 5 days elicited significant angiogenesis in the mesenteric windows. L-NAME (0.5 g/L in drinking water) caused further enhancement of the angiogenic response produced by human recombinant bFGF (p<0.001), bovine purified bFGF (p<0.05) or murine recombinant IL-1 (p<0.05). In contrast, the L-NAME treatment did not affect the angiogenic response produced by human and murine recombinant VEGF165. These data suggest that nitric oxide can act as an endogenous suppressor of mammalian de novo angiogenesis, which is a new finding, and, moreover, that angiogenesis induced by VEGF165 on the one hand and by bFGF and IL-1 on the other in the rat mesenteric window depends on different pathways.
Department of Pathology, Göteborg University, Sahlgrenska University Hospital, Sweden.
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Norrby
D000818:Animals; D002417:Cattle; D016228:Endothelial Growth Factors / Q000494:pharmacology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008222:Lymphokines / Q000494:pharmacology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D009569:Nitric Oxide / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D007375:Interleukin-1; D008222:Lymphokines; D011994:Recombinant Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D016222:Fibroblast Growth Factor 2; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester