Lysozyme and dandelion extract alleviate tearing eye disease by reducing inflammation and oxidative stress through canine corneal fibroblast model established.

Tearing around the eyes was a common health problem in dogs and cats. The alleviating effects of lysozyme and dandelion extract on inflammatory reaction of canine corneal fibroblasts induced by lipopolysaccharide (LPS) were systematically investigated. Based on inflammatory model established, inflammatory factors (IL-6, IL-8, IL-10, TNF-α) and oxidative stress indicators (SOD, CAT, GSH, MDA) were utilized to evaluate inflammatory response. The anti-inflammatory mechanisms of the two substances were also explored by transcriptome sequencing. The results demonstrated that lysozyme and dandelion extract at a safe concentration (1-10 µg/mL) could significantly reduce the release of nitric oxide by 59%-72% (P < 0.05), increase the concentrations of SOD, CAT and GSH by 2-9 times (P < 0.05), and decrease the concentration of MDA by 35%-61% (P < 0.05). The concentrations of IL-6, IL-8 and TNF-α decreased by 10%-44% (P < 0.05), while the concentrations of IL-10 and LXA-4 increased by 21%-39% (P < 0.05). The number of migrating cells increased by 42%-56% (P < 0.05). Therefore, the two substances alleviated oxidative damage, inhibited the production of inflammatory factors and improved cell migration ability. Transcription GO enrichment results confirmed that lysozyme and dandelion extracts could up-regulate the gene expression of "structural molecule activity" and "ribosome" terms. The results of KEGG enrichment showed that lysozyme affected "ribosome" and other pathways, while dandelion extract participated in "axon guidance", "amoebiasis", "ECM-receptor interaction", "focal adhesion" pathways, which meant that lysozyme and dandelion extract exert crucial function in alleviating corneal cell inflammation by affecting the expression of genes or enzymes in these pathways. These findings could provide significant insights into reducing tearing eye inflammation in canine and strategies for preventing or removing tears and tear residue with lysozyme and dandelion extract.