Fig. 4
Changes in STAT1 pathway in H2S induced macrophage polarization. a Schematic illustration. b Relative mRNA expressions of M1/M2-related genes. The mRNA expressions of TNF-α and IL-1β of THP-1-derived macrophages were upregulated in the NaSH group and downregulated in the HA group and NaSH + pSTAT1 inhibitor groups compared with the NaSH group. The mRNA expressions of arginase-1 and DECTIN showed no changes. N = 3, **P < 0.01, ***P < 0.001 versus control. ###P < 0.001 versus NaSH. c Representative immunocytochemical images of THP-1 derived macrophages. CD68-positive (green) and iNOS-positive (red) M1 macrophage polarization increased after NaSH treatment, which decreased significantly after HA or NaSH + phospho-STAT1 inhibitor treatment compared with the NaSH group. Meanwhile, CD68-positive (green) and CD163-positive (red) M2 macrophage polarization exhibited no change in the four groups. Scale bar: 50 μm. ***P < 0.001 versus control, ###P < 0.001 versus NaSH. d Western blot results and semi-quantifications of iNOS, TNF-α, arginase-1, phosphorylation of STAT1, and total STAT1 expression in macrophages. iNOS and TNF-α expressions were upregulated after NaSH application and were decreased by HA application or additional administration of pSTAT1 inhibitor with NaSH. The proportion of pSTAT1/STAT1 was upregulated after NaSH application and was partially reversed by HA application or by additional administration of pSTAT1 inhibitor. Beta-actin served as the internal control for equal loading. Data represent three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 versus control, #P < 0.05, ##P < 0.01, ###P < 0.001 versus NaSH, &P < 0.05 versus HA