The Therapeutic Effects and Possible Mechanism of Pranoprofen in Mouse Model of Corneal Alkali Burns

Preparation and in vitro and in vivo evaluation of an isoliquiritigenin-loaded ophthalmic nanoemulsion for the treatment of corneal neovascularization

Isoliquiritigenin (ISL), as a natural flavonoid, has been proven to have therapeutic potential for corneal neovascularization (CNV) treatment; however, its therapeutic use is restricted due to its poor aqueous solubility and limited bioavailability. To overcome these limitations, a novel ISL-loaded nanoemulsion (ISL-NE) was designed for inhibiting CNV in this study. ISL-NE formulation was composed of propylene glycol dicaprylate (PGD), Cremophor® EL (EL35), polyethylene glycol 400 (PEG 400) and adding water with sodium hyaluronate, its particle size was 34.56 ± 0.80 nm with a low polydispersity index of less than 0.05, which suggested a narrow size distribution. The results demonstrated that ISL-NE released higher and permeated more drug than ISL suspension (ISL-Susp) in in vitro drug release and ex vivo corneal permeation study. ISL-NE showed no cytotoxicity in human corneal epithelial cells toxicity study, which was consistent with the result of ocular irritation study in rabbit eyes. ISL-NE had bioavailability 5.76-fold, 7.80-fold and 2.13-fold higher than ISL-Sups in tears, cornea and aqueous humor after a single dose of ISL-NE, respectively. Furthermore, the efficacy of ISL-NE treatment (0.2% ISL) was comparable to that of dexamethasone treatment (0.025%) in the inhibition of CNV in mice model. Enzyme-linked immunosorbent assay (ELISA) showed that the expressions of corneal vascular endothelial growth factor (VEGF-A) and matrix metalloproteinase (MMP-2) were decreased. In conclusion, the ISL-NE demonstrated excellent physicochemical properties, good tolerance, and enhanced ocular bioavailability. It could be a promising, safe, and effective treatment for CNV.

Lycium barbarum polysaccharide promotes corneal Re-epithelialization after alkaline injury

Chemical injury of the cornea results in epithelial defect and subsequent stromal scarring and infection. Our study aims to evaluate the effectiveness of pre-treatment of Lycium barbarum polysaccharide (LBP) in promoting corneal re-epithelialization after alkaline burn. The corneas of C57BL/6J mice were pre-treated with topical phosphate-buffered saline or LBP (0.2/2/20 mg/mL) for 7 days, following by 0.1M sodium hydroxide injury for 30 s and washing with distilled water for another 30 s. Area of epithelial defect and thickness of cornea were evaluated. Inflammatory cytokines and water channel expression levels were assessed using immunohistochemistry and Western blot. Compared to the injury group, mice with 2 mg/mL LBP pre-treatment revealed a significant decrease in fluorescein stained area after injury (p = 0.025), with increased epithelial layer thickness (p = 0.004). The corneal opacity was significantly reduced in the group with 2 mg/mL LBP pre-treatment followed by injury (p = 0.02). The expression of matrix metalloproteinase 12 (p = 0.033), platelet derived growth factor-BB (p = 0.031), and aquaporin 5 (p = 0.022) resulted in a decrease in expression level in group with 2 mg/mL LBP pre-treatment. Our results showed that 2 mg/mL LBP, with no apoptotic effect on corneal cells, promoted corneal epithelial growth and minimized disruption of the collagen architecture after injury in vivo. We suggest that LBP, as a natural Traditional Chinese Medicine, may potentially be a novel topical pre-treatment option for patients highly susceptible to ocular injury.

Roles and Mechanisms of Regulated Necrosis in Corneal Diseases: Progress and Perspectives

Regulated necrosis is defined as cell death characterized by loss of the cell membrane integrity and release of the cytoplasmic content. It contributes to the development and progression of some diseases, including ischemic stroke injury, liver diseases, hypertension, and cancer. Various forms of regulated necrosis, particularly pyroptosis, necroptosis, and ferroptosis, have been implicated in the pathogenesis of corneal disease. Regulated necrosis of corneal cells enhances inflammatory reactions in the adjacent corneal tissues, leading to recurrence and aggravation of corneal disease. In this review, we summarize the molecular mechanisms of pyroptosis, necroptosis, and ferroptosis in corneal diseases and discuss the roles of regulated necrosis in inflammation regulation, tissue repair, and corneal disease outcomes.

Role of anterior segment optical coherence tomography angiography in the assessment of acute chemical ocular injury: a pilot animal model study

To examine the use of anterior segment-optical coherence tomography angiography (AS-OCTA) in the assessment of limbal ischemia in an animal model chemical ocular injury. We conducted a prospective study using an established chemical ocular injury model in 6 rabbits (12 eyes), dividing the cornea limbus into 4 quadrants. Chemical injury grade was induced based on extent of limbal injury (0 to 360 degrees) and all eyes underwent serial slit-lamp with AS-OCTA imaging up to one month. Main outcome measure was changes in AS-OCTA vessel density (VD) comparing injured and control cornea limbal quadrants within 24 h and at one month. AS-OCTA was able to detect differences in limbal VD reduction comparing injured (3.3 ± 2.4%) and control quadrants (7.6 ± 2.3%; p < 0.001) within 24 h of ocular chemical injury. We also observed that AS-OCTA VD reduction was highly correlated with the number of quadrants injured (r = − 0.89; p < 0.001; 95% CI − 5.65 to − 1.87). Corneal vascularization was detected by AS-OCTA in injured compared to control quadrants (10.1 ± 4.3% vs 7.0 ± 1.2%; p = 0.025) at 1 month. Our animal pilot study suggests that AS-OCTA was able to detect limbal vessel disruption from various severities of acute chemical insult, and in the future, could potentially serve as an adjunct in providing objective grading of acute ocular chemical injury once validated in a clinical trial.