Hydrogen Sulfide-Releasing Compounds Decrease Prostaglandin E2 production in Cultured Porcine Iris-Ciliary Body Explants Exposed to Lipopolysaccharide-Induced Inflammation

Abstract

Purpose : We have evidence that both fast- and slow-releasing hydrogen sulfide (H₂S) compounds decreased lipopolysaccharide (LPS)-induced TNFα production in porcine iris-ciliary body (ICB) explants (Ohia et al. Invest. Ophthalmol. Vis Sci., 2023; 63:2123-F0139). In the present study, we investigated the pharmacological actions of both fast- and slow-releasing H2S compounds on prostaglandin E2 (PGE2) production in cultured porcine ICB explants exposed to LPS.

Methods : Freshly isolated porcine ICB explants were cut into quadrants and cultured in Roswell Park Memorial Institute (RPMI) 1640 medium containing 1% penicillin-streptomycin. Explants were then exposed to different concentrations of LPS for 20 h. When used, H₂S-releasing compounds, sodium hydrosulfide (NaHS) and GYY4137 were added to media 15 mins and 30 mins, respectively, before the end of the incubation period. Concentrations of PGE2 in culture supernatants were measured using ELISA kit purchased from Cayman chemical company.

Results : LPS (25 ng/ml – 100 ng/ml) elicited increases in PGE2 production in cultured ICB explants over basal levels (2.6 ± 0.1 ng/ml/mg protein, n = 4). For instance, LPS 25 ng/ml, 50 ng/ml, and 100 ng/ml enhanced PGE2 production up to 6.2 ± 0.3 ng/ml/mg protein (n = 4), 11.8 ± 0.2 ng/ml/mg protein (n = 4) and 13.4 ± 0.3 ng/ml/mg protein (n = 4), respectively. In the presence of LPS (50 ng/ml), both NaHS (1 µM – 300 µM) and GYY4137 (0.01 µM – 100 µM) caused concentration-dependent decreases in LPS-induced PGE2 release from porcine ICB explants. For instance, GYY4137 (0.1 µM and 10 µM) evoked significant (p < 0.001) reductions of LPS-induced PGE2 production by 43.8 % ± 1.4 % (n = 3) and 40.2 ± 1.7 % (n = 3), respectively.

Conclusions : We conclude that both fast- and slow-releasing H₂S compounds can decrease LPS-induced PGE2 production in the porcine ICB explants supporting an anti-inflammatory role for this gas in the anterior uvea.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.