CORTICOSTEROID SUPPRESSION OF TRAUMA-INDUCED HYALURONAN IN RABBIT CORNEA AND AQUEOUS

BACKGROUND: Corneal and aqueous hyaluronan have recently been shown to react in response to several different types of trauma, including cat aract surgery. In order to find ways to influence the reaction, we hav e evaluated the effect of topical dexamethasone (Isopto-Maxidex(R), Al con Universal Ltd, Fort Worth, Tex) or indomethacin (Confortid(R), Dum ex Ltd, Copenhagen, Denmark) on the postoperative hyaluronan concentra tion in rabbit cornea and aqueous after extracapsular lens extraction. METHODS: The drugs were administered as topical eye drops three times daily. The hyaluronan concentration in rabbit cornea and aqueous afte r extracapsular lens extraction was measured with a radioligand assay. RESULTS: Dexamethasone treatment (1 mg/mL) significantly suppressed t he increase in corneal hyaluronan seen after extracapsular lens extrac tion, 2 (p less than or equal to 0.0022) and 3 weeks (p less than or e qual to 0.0002) after surgery, while indomethacin did not induce any s ignificant difference at 2 weeks. When the dexamethasone concentration was lowered to 0.1 and 0.2 mg/mL, there was still a significant decre ase (p less than or equal to 0.009) in hyaluronan concentration, but a t lower concentrations of dexamethasone (0.01 and 0.02 mg/ mL), no sig nificant decrease was seen. The increase in aqueous hyaluronan concent ration seen 2 days after surgery in untreated eyes was significantly l owered by both dexamethasone (p less than or equal to 0.0076) and indo methacin (p<0.036). CONCLUSIONS: Dexamethasone lowers reactive corneal and aqueous hyaluronan concentration in vivo after extracapsular lens extraction.