3 mercaptopyruvate

After confluence attainment myoblasts were plated in proper cell culture plates (Corning Costar, Sigma-Aldrich, Milan, Italy) according to experimental procedures. Once differentiated in myotubes, they were treated with 1 µM DEX (Sigma Aldrich, Milan, Italy) for 48 h. Glucoraphanin (30 µM), purified from Tuscan black kale seeds by Bologna laboratory (CREA-AA; previously CRA-CIN) according to a previously described method [83 (link)], L-cysteine (150 µM) and 3-mercaptopyruvate (150 µM) (Sigma-Aldrich, Milan, Italy) were used in the presence of DEX. All treatments were done in DM. Concentration and time of exposure for DEX-induced damage were previously set up [30 (link)]; glucoraphanin concentration was chosen based on the ability of the compound to increase the intracellular H₂S concentration [84 (link)]; L-cysteine and 3-mercaptopyruvate concentrations were chosen based on previously obtained results [29 (link)].

3-aminophthalhydrazide (luminol), 1-(p-hydroxyphenyl)imidazole (HPI), disodium sulfide (Na₂S), erastin, RSL3, cumene hydroperoxide (CHP), liproxstatin-1, 7-(diethylamino)coumarin-3-carbohydrazide (CHH), 4-hydroxytamoxifen (Tam), monobromobimane (MBB), cysteine (Cys), 3-mercaptopyruvate (3MP), cytochrome c (cyt c), glutathione reductase (GR), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), S-nitrosoglutathione (GSNO), ferrocene, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPOL) and isopropyl β-d-1-thiogalactopyranoside (IPTG) were obtained from Sigma-Aldrich. BODIPY C11, diallyl tetrasulfide (DATS) and Amplex Red were obtained from Thermo Fisher Scientific. DEPMPO was obtained from Enzo. H₂O₂ was obtained from Roth. GSH and 5-aminolevulinic acid hydrochloride were obtained from Merck. Sodium disulfide (Na₂S₂), sodium tetrasulfide (Na₂S₄) and 3′,6′-di(O-thiosalicyl)fluorescein (SSP4) were obtained from Dojindo. The synthesis of GSSSG, GS³⁴SSG and GSSSSG was performed as described previously⁴³ . CSSSC was synthesized as described below.