The stromal layer is the thickest layer of the cornea, and corneal stromal cells play an important role in the inflammatory response and wound repair. This study investigated the effect of MCC950, an inhibitor of NLRP3 inflammasome, on the inflammatory response and proliferation of canine corneal stromal cells (CCSCs) induced by Staphylococcus pseudintermedius (S. pseudintermedius).

CCSCs were pretreated with MCC950 and infected with S. pseudintermedius. The phosphorylation of p65, IκBα, PI3K, and AKT and the expression of NLRP3, caspase-1 p20, cleaved IL-1β, ASC, β-catenin, c-Myc, and CyclinD1 were detected by western blotting. The expression of inflammatory factors (IL-1β, IL-6, IL-8, IL-18, and TNF-α) and growth factors (EGF, FGF, TGF-β1, VEGF, and CTGF) were measured by RT-PCR. The levels of MDA content and LDH activity were detected by an assay kit. The cell cycle was detected by flow cytometry.

MCC950 down-regulated the phosphorylation of p65, IκBα, PI3K, and AKT and decreased the expression of NLRP3, caspase-1 p20, cleaved IL-1β, ASC, β-catenin, c-Myc, and CyclinD1 compared to those in the S. pseudintermedius infection group (p < 0.05). MCC950 significantly inhibited the expression of inflammatory factors (IL-1β, IL-6, IL-8, IL-18, and TNF-α) and growth factors (EGF, FGF, TGF-β1, VEGF, and CTGF) induced by S. pseudintermedius (p < 0.01). Compared to the S. pseudintermedius infection group, the MDA content and LDH activity of CCSCs were significantly decreased after treatment with MCC950 (p < 0.01).

MCC950 attenuates S. pseudintermedius-induced inflammatory responses in CCSCs. At the same time, MCC950 can inhibit excessive proliferation of cells, which is beneficial for alleviating corneal fibrosis healing.