Role of Dectin-1 in the innate immune response of rat corneal epithelial cells to Aspergillus fumigatus

BACKGROUND To observe Dectin-1 expression in fungal keratitis on rat models and to determine the role of Dectin-1 in innate immune response to Aspergillus fumigatus. METHODS Wistar rats were randomly divided into control, fungal keratitis and pretreatment (pretreated with Laminarin) groups. Samples were used for conducting immunohistochemical staining and real-time PCR to observe expression of cytokines like CCL2, CCL3, CXCL1, CXCL2, IL-1β, TNF-α, IL-6, IL-10. RESULTS After fungal stimulations, all 7 inflammatory factors, except IL-10, increased with different levels. After 4 h of fungal stimulations, IL-1β, IL-6, CCL2, CXCL1 and CXCL2 of pretreatment groups were significantly (p < 0.05) lower than fungal groups, while the other 3 cytokines had no significant changes. After 8 h of fungal stimulations, IL-6 and CXCL1 of pretreatment groups were still significantly (p < 0.05) lower than fungal groups. DISCUSSION With progress of fungus stimulation, expression of IL-1β,CXCL1 ,CXCL2,MCP-1 gradually increased, whilepretreated with Laminarin to block Dectin-1, these expression decreased, indicating that Dectin-1 maypromote immune reaction through them. IL-10 decreased in fungal group because of itsimmunosuppressive effect at 4h, and it began to increase at 8h to suppress Th1 inflammation response inorder to avoid excessive tissue damage. CONCLUSION Dectin-1 in early period of innate immune responses in rat fungal keratitis might work through IL-1β, IL-6, CCL2, CXCL1, CXCL2 to recruit neutrophils and macrophages to participate anti-fungal immunity.