Therapeutic efficacy and safety of a multi-wavelength LED irradiation device in a rat model of meibomian gland dysfunction

This study aimed to evaluate the therapeutic efficacy and ocular safety of a multi-wavelength (680 nm, 780 nm, 830 nm) LED irradiation device in a rat model of meibomian gland dysfunction (MGD)-induced dry eye disease (DED). A total of 34 male SD rats were randomly assigned to eight experimental groups, including a normal control group, an MGD induction group, and various treatment groups (LED irradiation, hyaluronic acid, cyclosporine, thermal therapy, and combination therapy). MGD was induced by CFA injection. LED irradiation was administered daily from day 8 to day 22. The clinical ocular assessments included the following: tear break-up time (TBUT), eyelid swelling score, fluorescein corneal staining (FCS), and eyelid telangiectasia. Immunohistochemistry (IHC) analyses of IL-1β, IL-6, and TNF-α were conducted in the cornea, conjunctiva, meibomian glands, and retina. To assess retinal safety, a TUNEL staining procedure was performed. The LED and combination treatment groups showed significant enhancements in TBUT and reductions in FCS, eyelid swelling, and telangiectasia scores in comparison to the MGD group (p < 0.05). In-depth analysis of the data sets revealed a significant decrease in the expression of inflammatory cytokines among the treatment groups. Notably, the expression of IL-1β and IL-6 was significantly reduced in both the LED and combination groups.