Thymol Ameliorates Aspergillus fumigatus Keratitis by Downregulating the TLR4/MyD88/NF-kB/IL-1β Signal Expression and Reducing Necroptosis and Pyroptosis

Fungal keratitis is a refractory kind of keratopathy. We attempted to investigate the anti-inflammatory role of thymol on Aspergillus fumigatus (A. fumigatus) keratitis. Wound healing and fluorescein staining of the cornea were applied to verify thymol's safety. Mice models of A. fumigatus keratitis underwent subconjunctival injection of thymol. The anti-inflammatory roles of thymol were verified by hematoxylin-eosin (HE) staining, slit lamp observation, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting. In contrast with the DMSO group, more transparent corneas and less inflammatory cells infiltration were detected in mice treated with 50 mu g/ml thymol. Thymol downregulated the synthesis of TLR4, MyD88, NF-kB, IL-1 beta, NLRP3, caspase 1, caspase 8, GSDMD, RIPK3 and MLKL. In summary, we proved that thymol played a protective part in A. fumigatus keratitis by cutting down inflammatory cells aggregation, downregulating the TLR4/ MyD88/ NF-kB/ IL-1 beta signal expression and reducing necroptosis and pyroptosis.

Automated summary

Thymol was found to have an anti-inflammatory effect in Aspergillus fumigatus keratitis. Wound healing and fluorescein staining were used to confirm the safety of thymol. The study showed that treatment with 50 μg/ml thymol reduced the infiltration of inflammatory cells and increased corneal transparency. Thymol also downregulated the TLR4/MyD88/NF-kB/IL-1 beta signaling and reduced necroptosis and pyroptosis.