Increased nitric oxide production in endotoxin-induced uveitis. Reduction of uveitis by an inhibitor of nitric oxide synthase.
Nitric oxide (NO) has been implicated in the pathogenesis of several inflammatory diseases. In the present study, we investigated the potential role of NO in an ocular model of inflammation, endotoxin-induced uveitis (EIU), in Lewis rats. Injection of LPS in one footpad induces severe uveitis after 16 h, which is accompanied by an increase of NO in the aqueous and vitreous humors, as evaluated by nitrite assay. Reverse transcriptase-PCR experiments reveal a large increase of inducible NO synthase (iNOS) mRNA in the iris/ciliary body, from 2 to 24 h after LPS treatment. In the retina, maximal increase of iNOS mRNA was detected 16 h after LPS treatment. Two i.p. injections of the NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), which inhibits nitrite release in the aqueous and vitreous humors, profoundly reduce clinical and histologic inflammation in EIU rats. These results implicate the NO pathway in the pathogenesis of EIU and demonstrate the possibility of modulating this inflammatory disease by injection of a NOS inhibitor.
Goureau
O
O
INSERM U118, Gerontology Research Laboratory, Paris, France.
Bellot
J
J
Thillaye
B
B
Courtois
Y
Y
de Kozak
Y
Y
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors / Q000235:genetics; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004195:Disease Models, Animal; D004731:Endotoxins / Q000633:toxicity; D008297:Male; D008969:Molecular Sequence Data; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011914:Rats, Inbred BN; D011917:Rats, Inbred Lew; D014605:Uveitis / Q000209:etiology / Q000378:metabolism* / Q000517:prevention & control; D014822:Vitreous Body / Q000378:metabolism
D017931:DNA Primers; D004731:Endotoxins; D012333:RNA, Messenger; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester