Impaired wound healing and angiogenesis in eNOS-deficient mice

Abstract

A role for nitric oxide (NO) in wound healing has been proposed; however, the absolute requirement of NO for wound healing in vivo and the contribution of endothelial NO synthase (eNOS) have not been determined. Experiments were carried out using eNOS gene knockout (KO) mice to determine the requirement for eNOS on wound closure and wound strength. Excisional wound closure was significantly delayed in the eNOS KO mice (29.4 +/- 2.2 days) compared with wild-type (WT) controls (20.2 +/- 0.4 days). At 10 days, incisional wound tensile strength demonstrated a 38% reduction in the eNOS KO mice. Because effective wound repair requires growth factor-stimulated angiogenesis, in vitro and in vivo angiogenesis assays were performed in the mice to assess the effects of eNOS deficiency on angiogenesis. Endothelial cell sprouting assays confirmed in vitro that eNOS is required for proper endothelial cell migration, proliferation, and differentiation. Aortic segments harvested from eNOS KO mice cultured with Matrigel demonstrated a significant reduction in endothelial cell sprouting and [(3)H]thymidine incorporation compared with WT mice at 5 days. Capillary ingrowth into subcutaneously implanted Matrigel plugs was significantly reduced in eNOS KO mice (2.67 +/- 0.33 vessels/plug) compared with WT mice (10.17 +/- 0.79 vessels/plug). These results clearly show that eNOS plays a significant role in facilitating wound repair and growth factor-stimulated angiogenesis.

Involvement of Endothelial Nitric Oxide in Sphingosine-1-Phosphate–Induced Angiogenesis

“…23 Murohara et al 4 reported that angiogenesis in response to tissue ischemia or VEGF administration was significantly impaired in eNOS-deficient mice. An angiogenesis-promoting role for EC-derived NO was also suggested in the report by Lee et al, 21 who showed impaired wound healing and angiogenesis in eNOS-deficient mice. We observed that there was a marked reduction in the number of infiltrating capillaries containing red blood cells within Matrigel plugs taken from L-NAME-treated mice compared with untreated mice.…”

“…Interestingly, previous studies have demonstrated the crucial role of NO in wound healing, as wound healing is accelerated by systemic administration of L-arginine, a substrate of NOS, but delayed by NOS inhibitors. 19,20 Lee et al 21 reported impaired wound healing and angiogenesis in eNOS-deficient mice. Together with those findings, our data demonstrating NO-dependent angiogenesis by S1P may account for the critical role of NO in wound repair.…”

“…4,21,23 With the in vivo rabbit cornea assay, angiogenesis induced by vasoactive molecules, including substance P, was shown to have been blocked by NOS inhibition. 23 Murohara et al 4 reported that angiogenesis in response to tissue ischemia or VEGF administration was significantly impaired in eNOS-deficient mice.…”

Nitric oxide synthase and NAD(P)H oxidase modulate coronary endothelial cell growth

“…The integrity of the endothelium therefore bears an enormous significance in physiological processese.g. wound healing after an injury to the vascular wall -where controlled proliferation and migration of endothelial cells are required [2]. However, several pathological conditions including coronary atherosclerosis, a major cause of morbidity and mortality in the Western World, are associated with an uncontrolled as well as accelerated proliferation and migration of both endothelial and VSMCs [5].…”

“…The integrity of the endothelial layer is preserved by controlled proliferation and migration of endothelial cells in a number of physiological processes such as angiogenesis and during wound healing after an injury to the vascular wall [2,3]. However, in several pathological conditions e.g.…”