Background/Purpose: Hydrogen sulfide (H₂S) has recently been proposed as an endogenous mediator of inflammation in several pathology models. The aim of this work was to study the possible role of H₂S as an anti-inflammatory and anti-oxidant agent in human articular chondrocytes (CHs) from osteoarthritic (OA) tissue.

Methods: We analyzed the effects of different concentrations of a fast (NaHS) or a slow (GYY4137) release H₂S donor on three key aspects of the inflammatory process in OA, namely: 1) Nitric oxide (NO) production and inducible NO synthase (iNOS) levels; 2) Production of reactive oxygen species (ROS) and antioxidant enzymes superoxide dismutase 2 (SOD2) and catalase (CAT); and 3) The production of prostaglandin E-2 (PGE-2) and cyclooxygenase (COX)-1, -2 and PGE synthase 1 (mPGES-1). NO production was quantified through the Griess reaction. Protein levels were visualized through immunocytochemistry and quantified with appropriate software; mRNA expression levels were detected with qRT-PCR. ROS levels were quantified with a fluorescence microscope after dihydrorhodamine treatment. PGE-2 levels were quantified with a specific EIA. For all studies cells were cultured in medium with 0.5% FBS and stimulated with 5 ng/ml of IL-1b and the different concentrations of NaHS and GYY4137 (ranging from 50 mM to 1000 mM) for 48h. ANOVA tests were performed and differences were considered significant when p<0.05.

Results: The concentrations of H₂S-donors used did not significantly affect cell viability (p>0.05). Concentrations higher than 100 µM of the sulfur donors were effective in reducing NO production in IL-1β stimulated OA CHs in a dose-dependent manner, probably by ameliorating the induction of iNOS synthesis, since both iNOS mRNA and protein levels were also reduced. ROS levels were reduced when 50 and 200 µM GYY4137 were used, but not by 1000 µM, and this was accompanied, at 200 µM GYY4137, by a reduction in the expression of SOD2 and CAT. NaHS was not effective in reducing ROS directly, and no correlation was found with SOD2 and CAT expression. PGE-2 values were reduced by all concentrations of GYY4137 and NaSH (except 1000 µM) and, in the case of GYY4137, both COX-2 and mPGES-1 were also downregulated at the higher concentrations (>100 µM) whereas COX-1 expression was not affected. Collectively, GYY4137 was found to be more effective than NaHS to ameliorate the IL-1β-induced OA-like markers of inflammation and oxidative damage, particularly at a 200 µM.

Conclusion: Results obtained so far suggest an anti-inflammatory and antioxidant role of certain H₂S donors which might be of interest in the alleviation of OA-related inflammation processes and that should be further explored as a therapeutic approach.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-effect-of-hydrogen-sulfide-donors-on-inflammatory-mediators-in-human-articular-osteoarthritic-chondrocytes/