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Abstract #8967 Published in IGR 5-2
Unoprostone isopropyl pretreatment decreases endothelin-1 release and the intraocular pressure spike induced by laser trabeculoplasty in the rabbit
Holló G; Visontai Z; Lakatos P; Vargha POphthalmologica 2003; 217: 231-236
PURPOSE: The authors have previously shown that the intraocular pressure (IOP) spike due to argon laser trabeculoplasty (ALT) is caused by an acute endothelin-1 (ET-1) release from the uveal tissue into the aqueous humor of rabbit eyes. In this study, they investigated whether pretreatment with topical unoprostone isopropyl, a functional antagonist of ET-1, protects against the pressure spike due to ALT in the rabbit model. METHODS: IOP of both eyes of 17 pigmented rabbits was measured with a TonoPen XL tonometer under general anaesthesia (baseline measurement). Then the right eyes were treated with topical unoprostone isopropyl 0.12% BID for six days, and the left eyes similarly received balanced salt solution (BSS) twice daily. After the last morning instillation, IOP of both eyes was measured under general anesthesia after two hours in group 1 and after three hours in group 2 animals. Then, for both groups, ALT was performed on both eyes. Thirty minutes after laser treatment (and still under general anesthesia), IOP was measured again. Then the aqueous humor was aspirated for measurement of ET-1 concentration. RESULTS: Baseline individual IOP differences (left eye minus right eye) were not significant in both groups: mean ± SD 0.25 ± 1.16 and -0.33 ± 0.71 mmHg, respectively (paired t test, p > 0.05 for both groups). On day 6, two (group 1) and three (group 2) hours after the last instillation but before laser trabeculoplasty, the difference (BSS-pretreated left eye minus unoprostone-pretreated right eye) increased to 2.13 ± 2.10 mmHg (p = 0.024) and 1.33 ± 0.71 mmHg (p = 0.0005), respectively. Thirty minutes after ALT, the IOP difference was 2.63 ±2.67 mmHg in group 1 (p = 0.027), but no difference was seen in group 2 (0.67 ± 1.94 mmHg, p = 0.332). In group 1, postoperative aqueous humour ET-1 concentration for the unoprostone-pretreated right eye was significantly lower than that for the BSS-pretreated left eye (paired t test, p = 0.01); but in group 2 no inter-ocular difference in ET-1 concentration was found (p = 0.976). CONCLUSIONS: Topical unoprostone pretreatment decreases laser-induced ET-1 release and diminishes the IOP spike caused by ALT in vivo within two hours after instillation, when the concentration of unoprostone in the aqueous humor is high.
Dr. G. Holló, Semmelweis University, First Department of Ophthalmology, 1083 Budapest, Tömö u. 25-29, Hungary. hg@szem1.sote.hu
Classification:
11.4 Prostaglandins (Part of: 11 Medical treatment)
