Direct, real-time, simultaneous monitoring of intravitreal nitric oxide and oxygen in endotoxin-induced uveitis in rabbits.
Nitric oxide (NO) plays a critical role in the pathogenesis of endotoxin-induced uveitis (EIU). Since NO is a labile free radical, it is difficult to examine the dynamics of NO directly in vivo. In this study, we established a system for direct monitoring of the dynamics of NO and partial pressure of oxygen (pO(2)) in EIU in rabbits. The currents (calculated concentrations) of NO and pO(2) in the vitreous were monitored after the intravitreal injection of lipopolysaccharide (LPS). In addition, the protein concentrations and nitrite levels in the aqueous humor were analyzed. The eyes were enucleated, and a histologic study was performed on their posterior segments. The tissue slices were also immunostained with anti-nitrotyrosine as a marker of peroxinitrite and/or nitrogen-related oxidants. The NO level decreased temporarily after LPS injection and then increased from 1 to 7 h. pO(2) increased temporarily for about 30 min after LPS injection. The change in NO current was inversely proportional to pO(2) after LPS injection and vice versa. The protein concentration and nitrite level after LPS injection increased significantly. These changes were suppressed by pretreatment with N(G)-nitro-l-arginine-methyl-ester. Immunohistochemical study showed enhanced immunoreactivity of nitrotyrosine in the inflamed retina. Since nitrotyrosine was detected, it appears that NO readily reacts with oxygen to produce cytotoxic species, peroxynitrite, and/or nitrogen-related oxidants. This process may be related to the retinal injury in EIU. This monitoring system can provide useful information on dynamic changes in intravitreal NO and pO(2) for understanding EIU.
Yomura
Yasue
Y
Department of Ophthalmology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae, Kawasaki, Kanagawa 216-8511, Japan.
Shoji
Yoko
Y
Asai
Daisuke
D
Murakami
Eiichi
E
Ueno
Satoki
S
Nakashima
Hideki
H
D000704:Analysis of Variance; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism; D004594:Electrophysiology; D005136:Eye Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D011817:Rabbits; D014605:Uveitis / Q000139:chemically induced* / Q000276:immunology / Q000378:metabolism*; D014822:Vitreous Body / Q000378:metabolism*
D005136:Eye Proteins; D008070:Lipopolysaccharides; D009573:Nitrites; D009569:Nitric Oxide; D010100:Oxygen