Abstract
Purpose:
Evidence from our laboratory demonstrates that hydrogen sulfide (H2S) (using sodium hydrosulfide, NaHS as a generator of H2S in biological tissues) can produce pharmacological effects in mammalian ocular tissues such as a decrease in intraocular pressure (IOP) in normotensive rabbits. In the present study we tested the hypothesis that the observed IOP-lowering effect of NaHS is mediated by an increase in aqueous humor outflow in porcine trabecular meshwork.
Methods:
Porcine ocular anterior segments explants containing only the trabecular meshwork were mounted on a perfusion chamber and perfused with Dulbecco’s Modified Eagle’s Medium (DMEM) at constant pressure of 7.35 mmHg and maintained at 37°C, 5% CO2. Once aqueous humor outflow was stable (~ 3 hours), ocular anterior segment explants were administered with different concentrations of NaHS (0.1 nM - 10 µM), and outflow was monitored for an additional 4 hours. Vehicle (0.1% saline) was run in parallel.
Results:
The fast releasing H2S donor, NaHS (0.1 nM - 10 µM) produced a concentration-dependent increase in aqueous humor outflow in ocular anterior segment explants. For instance, administration of NaHS (100 nM) caused a significant (p<0.01) enhancement [145 ± 14.61 % of basal (mean ± SE)] of aqueous humor outflow which lasted for an hour.
Conclusions:
NaHS can increase aqueous humor outflow in porcine trabecular meshwork indicating a pharmacological role for H2S in the regulation of IOP.
Keywords: 427 aqueous •
616 neurotransmitters/neurotransmitter systems •
633 outflow: trabecular meshwork