Inflammatory reaction via arachidonic acid cascade after intravitreal injection of endothelin-1.
OBJECTIVE
To investigate the characteristics of anterior chamber inflammatory reaction induced by intravitreal injection of endothelin-1 (ET-1).


METHODS
The time course of changes in aqueous protein concentration (APC) after intravitreal injection of 10(-4), 10(-5), 10(-6) and 10(-7) M ET-1 into rabbit eyes was measured with a laser flare-cell meter. The influence of a topical diclofenac sodium (DFNa) pre- and post-treatment was assessed. Aqueous prostaglandin E2 and leukotriene B4 concentration was quantified using a radioimmunoassay technique.


RESULTS
Intravitreal injection of 10(-4) and 10(-5) M ET-1 significantly increased APC, while 10(-6) and 10(-7) M ET-1 did not induce anterior chamber inflammation. After 10(-5) M ET-1 injection, APC reached a maximum at 4 h post-treatment and returned to a normal level 48 h after injection. Eyes treated with 10(-4) M ET-1 displayed a bi-phasic time course, with peak values observed 4 to 8 h as well as 48 h after administration. Pre- and post-treatment with topical DFNa completely suppressed the APC increase in the 10(-5) M ET-1 preparation, and considerably inhibited it in the 10(-4) M ET-1 preparation. After ET-1 injection, aqueous prostaglandin E2 concentration increased significantly, followed by an increase in APC. There were no changes in leukotriene B4 concentration.


CONCLUSIONS
ET-1 induces anterior chamber inflammation via the cyclooxygenase pathway of the arachidonic acid cascade. The lipoxygenase pathway is not involved in this reaction.
Shoji
N
N
Department of Ophthalmology, Musashino Red Cross Hospital, Tokyo, Japan. nobu_s@mua.biglobe.ne.jp
Oshika
T
T
Masuda
K
K
D000287:Administration, Topical; D000818:Animals; D000867:Anterior Chamber / Q000187:drug effects*; D001082:Aqueous Humor / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage; D004008:Diclofenac / Q000008:administration & dosage; D015232:Dinoprostone / Q000378:metabolism*; D019332:Endothelin-1 / Q000008:administration & dosage*; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D007249:Inflammation / Q000209:etiology / Q000378:metabolism; D007267:Injections; D007975:Leukotriene B4 / Q000378:metabolism; D008297:Male; D011817:Rabbits; D011863:Radioimmunoassay; D014606:Uveitis, Anterior / Q000209:etiology / Q000378:metabolism*; D014822:Vitreous Body
D016861:Cyclooxygenase Inhibitors; D019332:Endothelin-1; D005136:Eye Proteins; D004008:Diclofenac; D007975:Leukotriene B4; D015232:Dinoprostone