COX-2 inhibitors prolong trauma-induced elevations of iris hyaluronan.

PURPOSE: To investigate whether and how treatment with COX-2 inhibitors influences hyaluronan responses to a standardized trauma, argon laser induced iritis, in rabbits. METHODS: Two different COX-2 inhibitors were used, SC-236 and rofecoxib. The drugs were administered orally, 6 mg/kg/day and 1.5 mg/kg/day respectively. Iris and aqueous humor hyaluronan concentrations were measured with a radiometric assay at different time points after laser irradiation. RESULTS: The hyaluronan concentration in the iris increased 3-4-fold with a peak concentration of 129.1 microg/g wet weight 2 days after laser irradiation. It then decreased to normal values after 1 week. In eyes treated with either of the COX-2 inhibitors, iris hyaluronan concentrations did not decrease as rapidly and were significantly higher at day 4 and 7 when compared to drug untreated eyes. CONCLUSION: Treatment with COX-2 inhibitors prolongs trauma induced elevation of iris content of endogenous hyaluronan. This may be, at least partly, due to an inhibition of interstitial fluid pressure regulation.

Effects of sympathetic denervation on the hyaluronan content of the anterior segment in the normal and traumatized rabbit eye.

PURPOSE: To determine whether there is any involvement of sympathetic nerves in the regulation of ocular hyaluronan production in the normal and traumatized rabbit iris. METHODS: Unilateral sympathetic denervation was performed by removing the right superior cervical ganglion. Hyaluronan concentrations in the iris and aqueous were measured with a radiometric assay at various time intervals after denervation. Peripheral iridectomy was also performed in both denervated and non-denervated eyes. RESULTS: Hyaluronan concentrations in the iris tissue after denervation were observed to have increased after 1 day, reaching a peak of 129.6 +/- 5.7 microg/g wet weight at day 3. Two weeks later, hyaluronan concentrations had fallen back to normal levels. Ocular trauma with peripheral iridectomy in denervated eyes caused an increase of hyaluronan content of up to 253.5 +/- 30.5 microg/g wet weight, which was not significantly different from hyaluronan concentrations observed after the same trauma in non-denervated eyes. CONCLUSION: Cervical sympathetic denervation results in a moderate increase of the hyaluronan content in the rabbit iris and does not appear to influence the hyaluronan response of the iris to trauma.