Investigating the mechanism of action of neutrophils in regulating the regeneration of corneal nerve injury

PURPOSE: The rich nerve endings of the cornea play an important role in maintaining its structural integrity and normal function. In this study, we found that neutrophil clearance significantly delays the regeneration of damaged corneal nerve repair, but the exact mechanism is unclear.METHODS: A mouse model of a corneal nerve injury was established, samples from each group were collected for sequencing, and the expression matrix obtained was analyzed for bioinformatics. Differential expression analysis with and without neutrophil closure in corneal scraping was performed for enrichment analysis. The differential genes were then intersected with neutrophil-associated genes, and the obtained intersected genes were subjected to protein-protein interaction (PPI) network construction and a screening of the key genes. The expression of key genes in the presence or absence of neutrophil closures and the correlation of expression with other central nodes were observed. In addition, the immune infiltration between the two groups with and without neutrophilic closure was observed as well as the variation of immune cells between the high and low gene expression groups.RESULTS: We obtained a total of 546 differential genes and 980 neutrophil-associated genes, with 27 genes common to both. Molecular complex assay (MCODE) analysis yielded five key genes, namely: ITGB2, MMP9, EGF, SERPINE1, and PLAUR. ITGB2, SERPINE1, and PLAUR demonstrated increased high expression in the neutrophil-confined group and decreased expression of MMP9 and EGF, and the difference was more significant for MMP9 and EGF. We also observed the immune infiltration between the two groups with and without neutrophil confinement. The results showed that the infiltration of M0 macrophages, activated mast cells, and neutrophils was significantly different between the two groups. The levels of neutrophils were also shown to be lower in the MMP9 and EGF low expression groups and higher in the high expression group. CONCLUSION: Neutrophil confinement may significantly affect the expression levels of MMP9 and EGF. Strategies to inhibit MMP9 may have potential therapeutic benefits.