Topical Application of VitB6 Ameliorates PM2.5-Induced Dry Eye via NFκB Pathway in a Murine Model.

Background/Objectives: Dry eye (DE) is mainly characterized by dryness, foreign body sensation, eye pain and visual impairment. Their possible causes are mainly inflammation, tissue damage and neurosensory abnormalities, and vitamin B6 (VitB6) attenuates the inflammatory response by modulating the NF-κB pathway to quench reactive oxygen species (ROS). The aim of this experiment was to investigate the therapeutic effect of VitB6 eye drops on particulate matter 2.5 (PM2.5)-induced dry eye in mice. Methods: Mice induced with the dry eye group were first induced using PM2.5 eye drops in a standard environment for 14 days, and then treated with different concentrations of VitB6 eye drops for 14 consecutive days. The phenol red cotton test was used to measure tear production. Ocular inflammation index and tear film function were evaluated by slim microscopy. Hematoxylin-eosin (HE) staining was used to observe conjunctival and corneal structure. Periodate-Schiff (PAS) staining was used to quantify conjunctival goblet cells. Corneal cell apoptosis was determined by TUNEL assay. The expression of keratin 10 (K10) and p-NF-κB p65 was detected by immunofluorescent staining and Western blot analysis. Results: Mice using only the PM2.5 model all exhibited varying degrees of dry eye symptoms. VitB6 treatment increased tear secretion and reduced inflammatory indices in mice with increased nerve density and number of branches in the basement membrane of the corneal epithelium. Conclusions: We found that administering VitB6 eye drops has a therapeutic effect in PM2.5-induced DE. This observation suggests that VitB6 may be useful in the clinical therapy of DE.