MCC950 attenuates inflammation-mediated damage in canines with Staphylococcus pseudintermedius keratitis by inhibiting the NLRP3 inflammasome

Background: Bacterial keratitis is a common eye disease in dogs and can seriously affect vision. This study investigated the anti-inflammatory effect of MCC950 in the cornea of canines infected with Staphylococcus pseudintermedius (S. pseudintermedius). Methods: In vitro, canine cornea epithelial cells were pretreated with MCC950 and PDTC and then infected with S. pseudintermedius. The key proteins of the NF-0 pathway and NLRP3 inflammasome were detected by Western blotting, the levels of inflammatory factors were detected by qPCR, and the levels of MDA and LDH were detected by assay kit. In vivo, the canine keratitis model was established by injecting S. pseudintermedius into the corneal stroma layer. After treatment with MCC950, slit-lamp examinations were performed. Cornea tissue protein and RNA were extracted, and Western blotting was used to detect key proteins of the NF-kappa B pathway and NLRP3 inflammasome. qPCR was used to detect the inflammatory factors. Paraffin sections of corneal tissue were prepared for HE staining and immunohistochemical staining. Results: After MCC950 treatment, the expression levels of key proteins in the NF-kappa B pathway and NLRP3 inflammasome in canine cornea epithelial cells and corneal tissues were decreased, and the expression levels of IL-1 beta, IL-6, IL-8, IL-18 and TNF-alpha were reduced. Cellular MDA and LDH levels were decreased. In vivo, the degree of corneal opacity, edema, neovascularization and corneal injury area decreased after MCC950 treatment. Canine corneal sections showed that MCC950 attenuated neutrophil infiltration. Conclusion: MCC950 alleviates the inflammatory response to canine keratitis caused by S. pseudintermedius by inhibiting the activation of the NLRP3 inflammasome.