Background and ObjectivesLow-level light therapy (LLLT) is an application of low-power light for various purposes such as promoting tissue repair, reducing inflammation, causing analgesia, etc. A previous study suggested the effect of light emitting diode (LED) light with the wavelength of 740 nm for promoting wound healing of corneal epithelial cells. This current study aimed to confirm the effect of LLLT for managing inflammation of a dry eye disease (DED) mouse model. Materials and MethodsA total of 50C57BL/6 female mice were randomly grouped into 5 groups to compare the effect of LLLT:1) Control group, 2) Only LLLT group, 3) Dry eye group, 4) LLLT in dry eye group, and 5) Early treatment group. DED was induced with 4 daily injections of scopolamine hydrobromide and desiccation stress for 17 days, and LLLT at 740 nm was conducted once every 3 days. To analyze the effect of LLLT on the DED mouse model, tear volume, corneal surface irregularities, and fluorescence in stained cores were measured, and the level of inflammation was assessed with immunohistochemistry. ResultsThe DED mouse model showed significant deterioration in the overall eye condition. After LLLT, the amount of tear volume was increased, and corneal surface irregularities were restored. Also, the number of neutrophils and the level of inflammatory cytokines significantly decreased as well. ConclusionThis study showed that LLLT at 740 nm was effective in controlling the corneal conditions and the degree of inflammation in DED. Such findings may suggest therapeutic effects of LLLT at 740 nm on DED.

Purpose Data on the effects of direct particulate matter (PM) exposure on the eyes and the nose are limited. Here, an interleukin (IL)-17/neutrophil-dominant ovalbumin (OVA)/polyinosinic-polycytidylic acid (Poly(I:C)) mouse model was used to evaluate the effect of different-sized titanium dioxide (TiO 2 ) particles on the eyes and the nose. We also examined whether IL-17-neutralizing antibody (IL-17Ab) treatment could reverse TiO 2 effects. Methods The nasal cavities and conjunctival sacs of each mouse were challenged with OVA and Poly(I:C) to induce neutrophil-dominant inflammation and then exposed to micro- and nano-TiO 2 . Subsequently, IL-17Ab was administered to investigate the role of IL-17 and inflammatory parameters. Results Micro- and nano-TiO 2 resulted in significant decreases in tear-break-up time and increases in corneal damage. Airborne micro-TiO 2 also increased nasal rubbing and sneezing counts compared with the OVA/Poly(I:C). Micro-TiO 2 exposure increased infiltration of neutrophils and IL-17A+ cells in the conjunctival tissues and the nasal mucosae. In addition, these increased symptoms and inflammation in the eyes and the nose by micro-TiO 2 exposure were inhibited by the IL-17Ab, suggesting IL-17 dependency. Conclusions TiO 2 aggravated IL-17-induced eye and nose inflammation and the IL-17Ab alleviated inflammation in the OVA/Poly(I:C) mouse model. These results may help develop a therapeutic modality for PM exposure and provide evidence for PM-associated diseases.

Purpose: This study aimed to investigate the effect of 5mW low-level light therapy (LLLT) on corneal alkali burn rat model, as no prior research has examined this specific treatment parameter. Method: Eighteen male SD rats were randomly assigned to three groups: control, 5-minute LLLT, and 10-minute LLLT. Corneal alkali burns were induced using 1N NaOH, and LLLT was performed daily with an 830-nm LED device. Ocular signs and immunohistochemistry analysis were conducted. Result: LLLT-treated groups exhibited faster wound healing at 12 hours but had higher cataract incidence. Neovascularization and corneal opacity scores were significantly higher in LLLT-treated groups. Immunohistochemical analysis showed increased IL-1β and IL-6 levels in cornea and retina. Discussion: LLLT accelerated wound healing but increased cataract formation, corneal opacity, neovascularization, and inflammatory response in ocular tissues. LLLT may have therapeutic potential for corneal alkali burns, but further studies are necessary to optimize treatment parameters and mitigate adverse effects.