Abstract
Purpose :
We have previously reported that hydrogen sulfide (H2S)-releasing compounds such as sodium hydrosulfide and the substrate for the biosynthesis of this gas, L-cysteine can reduce intraocular pressure in rabbits (Salvi et al. 2016). In the present study, we investigated the pharmacological effects of L-cysteine and a slow-releasing H2S compound, AP67 on aqueous humor outflow facility in porcine trabecular meshwork using an ex vivo ocular anterior segment model under normal and elevated ocular perfusion pressure.
Methods :
Porcine ocular anterior segment explants were perfused with Dulbecco’s Modified Eagle’s Medium maintained at 37° C and gassed with 5% CO2 and 95% air, under a constant normal pressure of 7.35 mmHg or elevated pressure of 15 mmHg. Stabilized explants were exposed to L-cysteine (1-100 nM) or the H2S-releasing compounds AP67 (0.1-10 µM), and outflow was monitored for 4 hours. Vehicle (0.1% saline, was run in parallel experiments).
Results :
Under conditions of normal perfusion pressure, L-cysteine significantly (p < 0.01) increased aqueous humor outflow facility with maximal effects achieved at a concentration of 100 nM (150.6 ± 17.2% of basal). Under conditions of elevated perfusion pressure, L-cysteine also caused a significant (p < 0.01) increase in aqueous humor outflow facility with maximal effects achieved at a concentration of 100 nM (157.7 ± 19.8% of basal). AP67 (100 nM) also increased outflow facility reaching a maximal effect of 133.6 ± 17.5% of basal under conditions of elevated ocular perfusion pressure.
Conclusions :
We conclude that both the substrate for the biosynthesis of H2S and compounds that can release this gas in a biological system can increase aqueous humor outflow facility in porcine trabecular meshwork in both normal and elevated ocular perfusion pressure conditions. The observed ability of these agents to increase outflow of aqueous humor was independent of perfusion pressure.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.