Purchase this article with an account.
E.C. Leal, A. Manivannan, C. Aveleira, A. Serra, A. Castilho, T. Terasaki, K.–I. Hosoya, M. Cotter, A. Ambrósio, J.V. Forrester; Leukocyte Adhesion and Blood Retinal Barrier (BRB) Breakdown in Diabetic Retinopathy (DR): Role of Nitric Oxide (NO) . Invest. Ophthalmol. Vis. Sci. 2005;46(13):423.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose: Leukocyte adhesion to retina vessels is believed to be involved in the development of DR by capillary occlusion. Some evidences also indicate that NO might be involved in BRB breakdown. We investigated the role of NO in leukocyte adhesion to retina vessels and in BRB breakdown in DR. Methods: Leukocytes, from spleens of normal mice, were labelled with calcein–AM and transferred to normal, diabetic, or diabetic treated (with NO synthase inhibitors, L–NAME or aminoguanidine) mice. After Evans Blue infusion, retinas were flat mounted and examined for cell adhesion and vessel leakage under confocal microscope. In vivo leukocyte adhesion was assessed using a scanning laser ophthalmoscope. We also used an endothelial cell line (TR–iBRB2). Cells were incubated with high glucose or NOC–18 and expression of adhesion molecules (ICAM–1, V–CAM–1) and tight junction proteins (ZO–1 and occludin) was assessed by flow cytometry and western blot, respectively. In vitro adhesion assay was accessed with a fluorescence plate reader. Results: BRB permeability and leukocyte adhesion are increased in diabetic mice. L–NAME but not aminoguanidine, prevented the diabetes–induced adhesion. In vitro, high glucose increased adhesion of leukocytes to endothelial cells. NOC–18, but not high glucose, increased ICAM–1 levels. VCAM–1 was not detected in TR–iBRB2. Occludin expression, in endothelial cells, was not altered by high glucose or NOC–18, but high glucose decreased ZO–1 levels. Conclusions: These results show that leukocyte adhesion to mouse retina vessels in diabetes involves a constitutive form of NOS since L–NAME but not aminoguanidine prevent the diabetes–induced adhesion. In vitro studies also support the idea that leukocyte adhesion involves NO pathways. BRB permeability is also increased in the diabetic mouse, but NO blockade did not appear to affect BRB permeability. In addition, NO did not alter tight junction protein levels in endothelial cells in vitro.
This PDF is available to Subscribers Only