| Summary: | IL-8 is highly expressed in tears of keratoconus patients, but its mechanism is still unclear. Abnormal collagen synthesis and degradation are one of the pathogenesis of keratoconus. In this study, the effect of IL-8 on collagen synthesis in corneal fibroblasts and its molecular mechanism were discussed to provide reference for clarifying the pathogenesis of keratoconus. siRNA interference system was established and the expression of IL-8 in corneal fibroblasts was silenced by siRNA. The expression changes of genes related to collagen synthesis and degradation as well as other pro-inflammatory factors after IL-8 silence were analyzed by real-time fluorescent quantitative PCR. The content of total collagen and the activity of MMP-2 were detected by ELISA and gelatin zymography, respectively. Western blot was used to analyze the expression changes of the key proteins of related signal pathway. The results show that the total collagen content and the expression of collagen synthesis genes (COL1A2, COL3A1, COL5A3 and COL6A1) increased significantly after IL-8 silencing, while the expression and activity of MMP-2 which participated in collagen degradation decreased. In addition, silencing IL-8 reduced the gene expression of IL-6, IL-1β, and VEGFA/VEGFR2, as well as the protein expression of AKT and ERK1/2 in downstream signal pathway. IL-8 regulated the expression of VEGF and other pro-inflammatory factors. It negatively regulated the collagen synthesis and participated in MMP-2 mediated collagen degradation in corneal fibroblasts through PI3K/AKT and ERK signaling pathways.
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