Clinical signs of acute ocular inflammatory response to endotoxin are not altered by increasing antioxidant potency of intraocular fluids.
Plasma antioxidant activity is due in large part to the ferroxidase activity of the copper (Cu) transport protein, ceruloplasmin. Implantation of osmotic pumps containing copper into rabbits resulted in a doubling of Cu concentration, ferroxidase activity, and antioxidant activity in plasma. Blood-ocular barriers essentially prevent the entry of large molecules such as proteins from plasma into the intraocular fluid compartments. However, during ocular inflammation, when these barriers are disrupted, plasma proteins can enter. Twenty-four hours after the induction of ocular inflammation by intraocular injection of endotoxin, the Cu concentration and antioxidant activity of intraocular fluids from the Cu pump animals was twice that of control groups, reflecting the differences in plasma levels. This is the first direct demonstration that alterations in plasma levels of ceruloplasmin can influence the antioxidant potency of the extracellular fluids. Increased intraocular fluid antioxidant activity did not affect the acute anterior segment response to endotoxin. However, it is possible that the time course and resolution of the response is altered by changes in extracellular fluid antioxidant activity. This possibility is currently under investigation.
McGahan
M C
MC
Department of Anatomy, Physiological Sciences and Radiology, School of Veterinary Medicine, North Carolina State University, Raleigh 27606.
Fleisher
L N
LN
Grimes
A M
AM
D000818:Animals; D000975:Antioxidants; D001082:Aqueous Humor / Q000378:metabolism; D002570:Ceruloplasmin / Q000378:metabolism; D003300:Copper / Q000097:blood / Q000494:pharmacology*; D004731:Endotoxins / Q000633:toxicity*; D011817:Rabbits; D014168:Transferrin / Q000378:metabolism; D014605:Uveitis / Q000503:physiopathology*
D000975:Antioxidants; D004731:Endotoxins; D014168:Transferrin; D003300:Copper; D002570:Ceruloplasmin