Comparison of RCI001 and corticosteroid on the effects on intraocular pressure in mice.

Purpose: RCI001, a novel therapeutic candidate for the treatment of ocular inflammatory diseases, have demonstrated remarkable anti-inflammatory and antioxidant effects in various ocular experimental models. This study was to evaluate the effects of RCI001 on intraocular pressure (IOP) and compare them with those of corticosteroids in experimental mouse models. Methods: Experimental mice were randomly divided into naïve, phosphate-buffered saline (PBS), 0.1% dexamethasone (DEX-1), and 1% RCI001 (RCI) groups, and each reagent was pipetted into the right eye of the mouse at 10 µL thrice daily for 5 weeks. In addition, 20 µL of 0.1% dexamethasone was injected subconjunctivally into the right eye once weekly for 5 weeks in the DEX-2 group. The IOP was measured under anesthesia at baseline and twice weekly for 5 weeks. The △IOP (%) was defined as the change in IOP from baseline [△IOP (%) = (IOPweek5-IOPbaseline)/IOPbaseline × 100%]. The anterior segments were clinically and histologically examined. Results: There was no significant increase in IOP and △IOP (%) [values by week 3 (day 21) in any of the groups]. However, IOP and △IOP (%) in the DEX-2 group tended to increase slightly after day 10 compared with baseline. Compared with baseline IOP values, the DEX-1 group showed a statistically significant increase in IOP at weeks 4 and 5, and the DEX-2 group at week 5. The △IOP (%) of the DEX-1 and DEX-2 groups (%) at week 5 were 38.2% ± 5.8% and 38.4 ± 4.6%, respectively. However, the IOP in the RCI group did not increase significantly until week 5. The RCI group did not show notable corneal changes, such as epithelial defects or stromal opacities, at week 5. In addition, hematoxylin and eosin (H&E) staining of corneas in the RCI group revealed healthy corneal epithelial, stromal, and endothelial integrity. Conclusion: Long-term use of RCI001 did not induce significant IOP elevation or ocular surface changes, whereas topical corticosteroids significantly increased the IOP. Therefore, RCI001 may be an effective anti-inflammatory agent with a low risk of drug-induced IOP elevation.

Comparison of Corneal Epithelial Wound Healing between Topical RCI001, Solcoseryl, and Polydeoxyribonucleotide in the Murine Ocular Alkali Burn Model.

PURPOSE: To compare the corneal epithelial wound healing effects of RCI001, Solcoseryl, and polydeoxyribonucleotide (PDRN) in a rat alkali burn model. METHODS: In 40 male Sprague-Dawley rats, we induced alkali burn using filter paper soaked in 0.2N sodium hydroxide. The rats were then treated with topical 0.5% RCI001, 1.0% RCI001, Solcoseryl, or PDRN twice a day for 2 weeks. Corneal epithelial integrity and epithelial healing rate were measured at day 0, 3, 5, 7, 10, and 14. Histologic and immunohistochemistry findings were also assessed. RESULTS: Both the 0.5% and 1.0% RCI001 groups showed significantly more epithelial healing compared to the control group at day 5, 7, 10, and 14 (each p < 0.05). No statistical difference was found between the 0.5% and 1.0% RCI001 groups. Neither the Solcoseryl nor the PDRN groups showed a significant difference from the control. RCI001 treatment resulted in significantly reduced stromal edema, and a trend towards less inflammatory cell infiltration. CONCLUSIONS: Topical application of RCI001 showed enhanced corneal epithelial wound healing in the murine corneal alkali burn model, presumably by suppressing inflammation. Meanwhile, Solcoseryl and PDRN did not show sufficient therapeutic effects compared to RCI001.

Investigating the Anti-Inflammatory Effects of RCI001 for Treating Ocular Surface Diseases: Insight Into the Mechanism of Action.

The ocular surface is continuously exposed to various environmental factors, and innate and adaptive immunity play crucial roles in ocular surface diseases (OSDs). Previously, we have reported that the topical application of RCI001 affords excellent anti-inflammatory and antioxidant effects in dry eye disease and ocular chemical burn models. In this study, we examined the inhibitory effects of RCI001 on the Rac1 and NLRP3 inflammasomes in vitro and in vivo. Following RCI001 application to RAW264.7 and Swiss 3T3 cells, we measured Rac1 activity using a glutathione-S-transferase (GST) pull-down assay and G-protein activation assay kit. In addition, we quantified the expression of inflammatory cytokines (interleukin [IL]-1ß, IL-6, and tumor necrosis factor [TNF]-α) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells using ELISA and real-time PCR. In the mouse ocular alkali burn model, RCI001 was administered via eye drops (10 mg/mL, twice daily) for 5 days, and 1% prednisolone acetate (PDE) ophthalmic suspension was used as a positive control. Corneal epithelial integrity (on days 0-5) and histological examinations were performed, and transcript and protein levels of Rac1, NLRP3, caspase-1, and IL-1ß were quantified using real-time PCR and western blotting in corneal tissues collected on days 3 and 5. We observed that RCI001 dose-dependently inhibited Rac1 activity and various inflammatory cytokines in LPS-stimulated murine macrophages. Furthermore, RCI001 restored corneal epithelial integrity more rapidly than corticosteroid treatment in chemically injured corneas. Compared to the saline group, activation of Rac1 and the NLRP3 inflammasome/IL-1ß axis was suppressed in the RCI001 group, especially during the early phase of the ocular alkali burn model. Topical RCI001 suppressed the expression of activated Rac1 and inflammatory cytokines in vitro and rapidly restored the injured cornea by inhibiting activation of Rac1 and the NLRP inflammasome/IL-1ß axis in vivo. Accordingly, RCI001 could be a promising therapeutic agent for treating OSDs.