Corneal Alkali Burn Research Articles

ALKBH5 Regulates Corneal Neovascularization by Mediating FOXM1 M6A Demethylation.

This study aims to explore the regulatory role and potential mechanisms of ALKBH5-mediated N6-methyladenosine (m6A) demethylation modification in corneal neovascularization (CNV). A mouse CNV model was established through corneal alkali burns. Total m6A levels were measured using an m6A RNA methylation quantification kit. The mRNA expression of candidate m6A-related enzymes was quantified by quantitative RT-PCR. Small interfering RNA targeting ALKBH5 was injected subconjunctivally into alkali-burned mice. The CNV area, corneal epithelial thickness, and pathological changes were evaluated. Protein expression was detected by western blot and immunofluorescence. Human umbilical vein endothelial cells (HUVECs) were treated with IL-6. Plasmid transfection knocked down ALKBH5 or overexpressed FOXM1 in IL-6-induced HUVECs. The assays of CCK8, wound healing, and tube formation evaluated the cell proliferation, migration, and tube formation abilities, respectively. The dual-luciferase assay examined the binding between ALKBH5 and FOXM1. Methylated RNA immunoprecipitation-qPCR detected the m6A levels of FOXM1. Significant CNV was observed on the seventh day. Total m6A levels were reduced, and ALKBH5 expression was increased in CNV corneas and IL-6-induced HUVECs. ALKBH5 knockdown alleviated corneal neovascularization and inflammation and countered IL-6-induced promotion of cell proliferation, migration, and tube formation in HUVECs. ALKBH5 depletion increased m6A levels and decreased VEGFA and CD31 expression both in vivo and in vitro. This knockdown in HUVECs elevated m6A levels on FOXM1 mRNA while reducing its mRNA and protein expression. Notably, FOXM1 overexpression can reverse ALKBH5 depletion effects. ALKBH5 modulates FOXM1 m6A demethylation, influencing CNV progression and highlighting its potential as a therapeutic target.

Bufalin Regulates STAT3 Signaling Pathway to Inhibit Corneal Neovascularization and Fibrosis After Alkali Burn in Rats

Purpose Bufalin (BU) is a bioactive ingredient extracted from the skin and parotid venom glands of Bufo raddei, which can effectively inhibit angiogenesis. The aim of this study was to investigate whether BU could affect corneal neovascularization (CoNV). Methods A rat CoNV model (right eye) was constructed by administration of NaOH, and the left eye served as a control. Corneal damage scores of rats were detected. Hematoxylin & eosin, TUNEL, and Masson staining examined pathological changes, apoptosis, and fibrosis of corneal tissues. Immunohistochemistry and western blotting assessed the expression of proteins. Results BU intervention resulted in a significant reduction in corneal inflammatory cells, repair of corneal epithelial hyperplasia, significant reduction in stromal edema, and reduction in vascular proliferation. BU can inhibit corneal neovascularization. Conclusion This study demonstrated that BU inhibits CoNV, fibrosis, and inflammation by modulating the STAT3 signaling pathway, elucidating the intrinsic mechanism of its protective effect. BU has great potential in the treatment of CoNV caused by corneal alkali burns.

Mesenchymal stem cells derived extracellular vesicles modified PLGA electrospinning nanofibrous scaffolds for corneal and retinal repair

Tissue self-renewal is crucial for ocular diseases such as corneal damage and retinal holes. In this study, a novel Poly (lactic-co-glycolic acid) (PLGA) electrospinning nanofibrous scaffold (PLGAENS), loaded with mesenchymal stem cells-derived extracellular vesicles (MSC-EVs), was developed to accelerate the healing of the cornea and retina. In-vitro experiments confirmed the supportive properties of PLGAENS, demonstrating its ability to promote cellular proliferation, migration, and extension. In the rat corneal alkali burn model and rabbit retinal hole model, MSC-EVs modified PLGAENS (PLGAMSC-EVs) accelerated the restoration of the corneal epithelium and stroma, as well as the closure of retinal holes. Additionally, miR-21-5p was identified as being enriched in MSC-EVs. Mechanistically, miR-21-5p suppressed scar formation by targeting the programmed cell death protein 4 (PDCD4) gene, reducing fibrosis and the expression of collagen-related genes, which helped maintain corneal transparency and retinal integrity. Overall, these findings underscored the potential of PLGAMSC-EVs in promoting ocular wound healing and suggested a promising new therapeutic strategy for the clinical treatment of corneal damage and retinal holes.

Anti-inflammatory and Restorative effects of milk exosomes and Dexamethasone-Loaded exosomes in a corneal alkali burn model

Corneal alkali burn is a common and challenging ocular trauma, necessitating the use of dexamethasone (DXMS) as a therapeutic agent. However, prolonged and frequent administration of this drug can lead to undesirable side effects, limiting its clinical application. This study aimed to investigate the role and mechanism of action of exosomes as drug carriers in corneal alkali burn repair. We employed centrifugation to isolate milk exosomes (EXO) as nanocarriers. We observed that EXO enhanced the activity and migration of corneal epithelial cells, expediting the repair process following corneal injury. Additionally, a nano-drug delivery model (DXMS@EXO) was designed using ultrasound to load DXMS into exosomes, thus enabling targeted delivery to inflammatory cells and enhancing drug efficacy. DXMS@EXO inhibited the inflammatory processes in the corneal alkali burn model by modulating the classical Wnt signaling pathway, thereby promoting corneal re-epithelialization and wound healing and accelerating the repair process of corneal alkali burn. Neither EXO nor DXMS@EXO exhibited significant side effects during the course of treatment. This study highlighted the substantial potential of EXO and DXMS@EXO in improving drug efficacy and facilitating the repair of corneal alkali burn.

Aloin alleviates corneal injury in alkali burn via inhibiting neutrophil extracellular traps and promoting Nrf2.

Ocular chemical burns are a leading cause of blindness. The cornea is injured by alkali-induced oxidative disturbances and an inflammatory response. The aim of this study was to evaluate the protective effects of aloin, an antioxidant, and anti-inflammatory compound, on corneal alkali burn. Mice eyes were injured by NaOH and subsequently treated with aloin eye drop and intraperitoneal injection. Pathological characteristics of the eyes were examined, and corneal samples were collected for further analysis. Aloin diminished neutrophil infiltration and the production of proinflammatory cytokines. Aloin also attenuated apoptosis in human corneal epithelial cells (HCEs) by reducing oxidative stress through the activation of the Nrf2 pathway. Additionally, aloin suppressed the formation of neutrophil extracellular traps (NETs) and inhibited their deposition on the cornea. Moreover, aloin mitigated alkali-induced apoptosis in HCEs caused by NETs. These findings suggest that aloin has potential as an antioxidant and anti-inflammatory compound for treating corneal alkali burn by inhibiting NETs formation and promoting Nrf2.

Phytic acid-loaded polyvinyl alcohol hydrogel promotes wound healing of injured corneal epithelium through inhibiting ferroptosis

As the important barrier of intraocular tissue, cornea is easy to suffer various kinds of injuries. Among them, acute alkali burn is a thorny ophthalmic emergency event, which can lead to corneal persistent epithelial defects, ulcers, and even perforation. Ferroptosis, a mode of regulatory cell death, has been found to play a key role in the process of corneal alkali burn, of which lipid peroxidation and intracellular iron levels are considered to be the possible therapeutic targets. To seek new effective treatments, the study herein focused on the occurrence of oxidative stress and ferroptosis in corneal alkali burn, exploring the role of phytic acid (PA), a natural small molecule with both antioxidant and iron chelating capacity, in the repair of corneal epithelial injury. The in vivo therapeutic results showed that PA eyedrops treatment promoted the recovery of corneal morphology and function, and in vitro experiments proved that PA prompted the repair of oxidative stress induced-corneal epithelial injury through ferroptosis inhibition. In addition, better drug treatment effect could be achieved through hydrogel delivery and sustained release, and our in vivo experiments showed the superior therapeutic effects of PA delivered by PVA hydrogels with larger molecular weights on corneal injury. In summary, this study demonstrated the excellent effect of natural small molecule PA with antioxidant and high efficiency chelating ferrous ions on ferroptosis inhibition, and showed the outstanding application prospect of PVA/PA hydrogels in the treatment of corneal epithelial injury.

The effect of platelet-rich plasma and sodium alginate hydrogel on corneal wound healing after corneal alkali burns in rats with computer-assisted anterior segment optical coherence tomography image analysis

Our objective was to determine the effect of a semi-synthetic sodium alginate hydrogel and its combination with platelet-rich plasma (PRP) on histopathological, biochemical, clinical, and anterior segment optical coherence tomography (AS-OCT) data. Alkali chemical burn of the cornea was induced. Injured rats were randomly divided into five equal groups and topically treated with phosphate-buffered saline (sham), platelet-rich plasma (PRP), 0.5% sodium citrate, a semi-synthetic sodium alginate hydrogel, or a combination of PRP and hydrogel (combined group) three times daily. The degree of corneal opacity (CO), corneal epithelial staining (CES), percentage of corneal epithelial defects (CEDP), degree of ciliary hyperemia (CH), neovascularization size (NVS), and extent of neovascularization (NVE) were evaluated. AS-OCT was performed at nine days, and then rats were sacrificed. Histological examination and enzyme-linked immunosorbent assays were performed to detect the concentrations of IL-1β and MMP-9 in the cornea. There were no significant differences between the groups regarding CEDP, CO, CES, CH, NVS, or NVE on the first day after corneal alkali burn injury (p > 0,05). At the last examination, CO was significantly lower in the PRP group than in the sham group (p = 0,044), while the CO concentrations were similar in terms of NVS (p > 0,05). Similarly, in terms of tissue MMP-9 levels, there were no significant differences between groups (p > 0,05). However, there was a significant difference in tissue IL-1β levels between the groups (p < 0,001). In the PRP and combined groups, the level of IL-1β was significantly lower than that in the sham group (p = 0,043 and p = 0,036, respectively). There was a significant difference in epithelial necrosis between the PRP, and it was the lowest in the combined group (p = 0,003). Epithelial thickness was highest in the combined group (p = 0,002). CEDP was significantly different at the last visit between the groups (p = 0.042). The fastest epithelial closing rate was observed for the combined group (p = 0,026). There was a significant negative correlation between tissue MMP-9 levels and corneal solidity and between tissue MMP-9 levels and the corneal area according to the AS-OCT measurements (p = 0,012 and p = 0,027, respectively). When used alone, topical hydrogel application did not significantly enhance the healing of corneal wounds. However, when combined with PRP, it leads to an increased rate of epithelial closure and neovascularization. This combination did not exacerbate inflammation or corneal opacity compared to PRP alone. The anticoagulant citrate solution in the PRP tube did not prove effective. The synergistic use of PRP and hydrogel could enhance epithelial thickness and reduce epithelial necrosis. The use of new parameters for corneal wound healing assessment was facilitated through AS-OCT image processing.

Engineered Mesenchymal Stromal Cell Exosomes-Loaded Microneedles Improve Corneal Healing after Chemical Injury.

Corneal alkali burns represent a prevalent ophthalmic emergency with the potential to induce blindness. The main contributing mechanisms include excessive inflammation and delayed wound healing. Existing clinical therapies have limitations, promoting the exploration of alternative methods that offer improved efficacy and reduced side effects. Adipose-derived stem cell-exosome (ADSC-Exo) has the potential to sustain immune homeostasis and facilitate tissue regeneration. Nevertheless, natural ADSC-Exo lacks disease specificity and exhibits limited bioavailability on the ocular surface. In this study, we conjugated antitumor necrosis factor-α antibodies (aT) to the surface of ADSC-Exo using matrix metalloproteinase-cleavable peptide chains to create engineered aT-Exo with synergistic effects. In both in vivo and in vitro assessments, aT-Exo demonstrated superior efficacy in mitigating corneal injuries compared to aT alone, unmodified exosomes, or aT simply mixed with exosomes. The cleavable conjugation of aT-Exo notably enhanced wound healing and alleviated inflammation more effectively. Simultaneously, we developed poly(vinyl alcohol) microneedles (MNs) for precise and sustained exosome delivery. The in vivo results showcased the superior therapeutic efficiency of MNs compared with conventional topical administration and subconjunctival injection. Therefore, the bioactive nanodrugs-loaded MNs treatment presents a promising strategy for addressing ocular surface diseases.

Preparation and in vivo and ex vivo studies of sirolimus nano-in-situ gel ophthalmic formulation

Sirolimus (SR) is a macrolide with antifungal and antitumor immunosuppressant properties, classified as a selective inhibitor of mammalian target of rapamycin (mTOR). In this study, an ionic in situ gel of SR (SR-SUS-ISG) was formulated using gellan gum, exhibiting stability regardless of temperature and pH variations, causing minimal irritation. Harnessing the physiological conditions of the eye, SR-SUS-ISG underwent gelation upon contact with ions, increasing drug viscosity and prolonging retention on the ocular surface. Concurrently, SR-SUS-ISG displayed favorable shear dilution properties, reducing viscosity at ambient temperature, enhancing fluidity, and facilitating convenient packaging and transport. Biocompatibility assessments on both human corneal epithelial cells and rabbit eyes demonstrated that SR-SUS-ISG could well be tolerated. Pharmacokinetic investigations in rabbit ocular aqueous humor revealed sustained release, improved corneal penetration, and enhanced bioavailability. Additionally, in a rat corneal alkali burn model, SR-SUS-ISG exhibited inhibitory effects on corneal neovascularization, associated with decreased levels of the inflammatory factors VEGF and MMPs. These findings suggested that SR-SUS-ISG held promise as an effective ocular drug delivery system.Graphical

Effect of Mesenchymal Stem Cells-Derived Exosomes on Healing of a Rabbit Model of Corneal Alkali Burn. Histological and Immunohistochemical Study

Abstract Introduction Corneal alkali burn is one of the most severe ophthalmic emergencies that requires prompt treatment. Recently, the attention of researchers has been attracted to the use of exosomes as a novel non-cell therapy for treatment of corneal alkali burn. Aim to evaluate the possible role of mesenchymal stem cells (MSCs)-derived exosomes on healing of experimentally induced corneal alkali burn in rabbits by histological and immunohistochemical techniques. Materials and Methods Forty-five adult male New Zealand white rabbits were divided into three groups: group I (control group); group II in which corneal alkali burn was left for spontaneous healing, and group III (exosomes treated group): in which rabbits received a sub-conjunctival injection of 100 μg MSCs-exosomes after one hour from corneal alkali burn induction. Injection of exosomes was repeated every other day. All groups were further subdivided into two subgroups; subgroup A and B, where corneal specimens were collected after 7 days and 14 days, respectively. Characterization of exosomes was done using transmission electron microscope. Gross examination of the cornea was done at days 0, 1, 4,7,10 and 14. At the end of experiment, corneal specimens were collected and subjected to hematoxylin and eosin, Masson`s trichrome, periodic acid Schiff, transforming growth factor-beta and vascular endothelial growth factor immunohistochemical techniques. Histo-morphometric study and statistical analysis were also done. Results Administration of MSCs-derived exosomes in group III improved healing of corneal alkali burn by inhibiting angiogenesis and inflammation, enhancing corneal reepithelization, and providing better organization of newly formed stromal collagen fibers. Conclusion Sub-conjunctival injection of MSCs-derived exosomes could be effective in the healing of corneal alkali burn in adult rabbits.

Anterior segment optical coherence tomography for superficial keratectomy

PurposeTo report the use of anterior segment optical coherence tomography (AS-OCT) for superficial keratectomy (SK) in anterior corneal opacity. MethodsThe characteristics of 43 eyes (39 patients) with various lesions responsible for anterior corneal opacity were included in this retrospective non-comparative study. AS-OCT was performed on all eyes before surgery. The thickness of corneal opacity and the underlying healthy stroma were measured. SK was performed on each individual. ResultsFour types of anterior corneal opacity were evaluated, including corneal degeneration (26/43), Reis-Bücklers corneal dystrophy (8/43), alkali burn (1/43) and corneal tumors (8/43). Based on AS-OCT images, all eyes showed abnormal hyper-reflective signals in the superficial cornea to less than one-third of the normal corneal thickness in the deepest corneal opacity. All 43 eyes underwent an SK procedure. In addition, 1 eye with alkali burns and 7 eyes with corneal tumors were combined with amniotic membrane transplantation. All eyes restored transparency without significant complications. ConclusionAS-OCT is a valuable method for objective preoperative and noninvasive assessments of anterior corneal opacities and is useful for guiding SK.

Retraction: Inhibited corneal neovascularization in rabbits following corneal alkali burn by double-target interference for VEGF and HIF-1α.

Retraction: Inhibited corneal neovascularization in rabbits following corneal alkali burn by double-target interference for VEGF and HIF-1α.

Tamarind seed polysaccharide-metformin insert: Higher ocular retention, slow-release, and efficacy against corneal burn

Metformin (MET) can be an alternative therapeutic strategy for managing ocular burn primarily because of its pleiotropic mechanism. Longer retention on the ocular surface and sustained release are necessary to ensure the efficacy of MET for ocular application. Although the high aqueous solubility of MET is good for formulation and biocompatibility, it makes MET prone to high nasolacrimal drainage. This limits ocular residence and may be a challenge in its application. To address this, polymers approved for ophthalmic application with natural origin were analyzed through in silico methods to determine their ability to bind to mucin and interact with MET. An ocular insert of MET (3 mg/6 mm) was developed using a scalable solvent casting method without using preservatives. The relative composition of the insert was 58 ± 2.06 %w/w MET with approximately 14 %w/w tamarind seed polysaccharide (TSP), and 28 %w/w propylene glycol (PG). Its stability was demonstrated as per the ICH Q1A (R2) guidelines. Compatibility, ocular retention, drug release, and other functional parameters were evaluated. In rabbits, efficacy was demonstrated in the 'corneal alkali burn preclinical model'. TSP showed potential for mucoadhesion and interaction with MET. With adequate stability and sterility, the insert contributed to adequate retention of MET (10–12 h) in vivo and slow release (30 h) in vitro. This resulted in significant efficacy in vivo.

Emodin suppresses alkali burn-induced corneal inflammation and neovascularization by the vascular endothelial growth factor receptor 2 signaling pathway.

To investigate the effects of emodin on alkali burn-induced corneal inflammation and neovascularization. The ability of emodin to target vascular endothelial growth factor receptor 2 (VEGFR2) was predicted by molecular docking. The effects of emodin on the invasion, migration, and proliferation of human umbilical vein endothelial cells (HUVEC) were determined by cell counting kit-8, Transwell, and tube formation assays. Analysis of apoptosis was performed by flow cytometry. CD31 levels were examined by immunofluorescence. The abundance and phosphorylation state of VEGFR2, protein kinase B (Akt), signal transducer and activator of transcription 3 (STAT3), and P38 were examined by immunoblot analysis. Corneal alkali burn was performed on 40 mice. Animals were divided randomly into two groups, and the alkali-burned eyes were then treated with drops of either 10 μM emodin or phosphate buffered saline (PBS) four times a day. Slit-lamp microscopy was used to evaluate inflammation and corneal neovascularization (CNV) in all eyes on Days 0, 7, 10, and 14. The mice were killed humanely 14 d after the alkali burn, and their corneas were removed and preserved at －80 ℃ until histological study or protein extraction. Molecular docking confirmed that emodin was able to target VEGFR2. The findings revealed that emodin decreased the invasion, migration, angiogenesis, and proliferation of HUVEC in a dose-dependent manner. In mice, emodin suppressed corneal inflammatory cell infiltration and inhibited the development of corneal neovascularization induced by alkali burn. Compared to those of the PBS-treated group, lower VEGFR2 expression and CD31 levels were found in the emodin-treated group. Emodin dramatically decreased the expression of VEGFR2, p-VEGFR2, p-Akt, p-STAT3, and p-P38 in VEGF-treated HUVEC. This study provides a new avenue for evaluating the molecular mechanisms underlying corneal inflammation and neovascularization. Emodin might be a promising new therapeutic option for corneal alkali burns.

Evaluation of the Treatment Effects of Conditioned Medium from Human Orbital Adipose-Derived Stem Cells in a Corneal Alkali Burn Rabbit Model.

Purpose: This study aimed to evaluate the effects of a new treatment-conditioned medium from human orbital adipose-derived stem cells (OASC-CM)-on corneal recovery after alkali burns in a rabbit model. Methods: The corneal alkali burn rabbit model was established and treated with OASC-CM, conditioned medium from human abdominal subcutaneous adipose-derived stem cells (ABASC-CM), and fresh control culture medium (con-CM) three times a day for 7 days, respectively. Subsequently, the treatment effects were evaluated and compared through clinical, histological, immunohistochemical, and cytokine evaluations. Results: Clinically, OASC-CM alleviated corneal opacity and edema and promoted recovery of corneal epithelium defect. Histologically and immunohistochemically, OASC-CM inhibited neovascularization, conjunctivalization, and immuno-inflammatory reaction, while promoting corneal regeneration and rearrangement. Increased secretion of interleukin-10 and inhibited protein levels of cluster of differentiation 45, interferon-γ, and tumor necrosis factor-α were observed in the alkali-burned cornea after OASC-CM treatment, which might be the relevant molecular mechanism. Conclusions: OASC-CM showed significant effects on the recovery of rabbit corneal alkali burns and eliminated immunological and ethical limitations, representing a new option for corneal wound treatment.

Imatinib@glycymicelles entrapped in hydrogel: preparation, characterization, and therapeutic effect on corneal alkali burn in mice.

Imatinib (IMB) is a type of tyrosine kinase inhibitor with great application potential for inhibiting corneal neovascularization (CNV), but its poor water solubility limits its application in eye disease treatment. In this study, novel IMB@glycymicelles entrapped in hydrogel (called IMB@glycymicelle-hydrogel) were prepared, characterized, and evaluated for their therapeutic effects on corneal alkali burn in mice. Imatinib could be successfully loaded in glycymicelles using glycyrrhizin as a nanocarrier with an optimized weight ratio of IMB:nanocarrier. The apparent solubility of IMB was significantly improved from 61.69 ± 5.55μg/mL to bare IMB to 359,967.62 ± 20,059.42μg/mL to IMB@glycymicelles. Then, the IMB@glycymicelles were entrapped in hydrogel fabricated with hydroxypropyl methylcellulose and sodium hyaluronate (HA) to prolong retention time on the ocular surface. Rabbit eye tolerance tests showed that IMB@glycymicelle-hydrogel possessed good ocular safety profiles. In a mouse model of corneal alkali burns, the topical administration of IMB@glycymicelle-hydrogel showed strong efficacy by prompting corneal wound healing, recovering corneal sensitivity, relieving corneal opacities, and inhibiting CNV, and these efficacy evaluation parameters were better than those of the positive drug HA. Overall, these results demonstrated that IMB@glycymicelle-hydrogel may be a promising candidate for the effective treatment of alkali ocular damage.

The application of a 4D-printed chitosan-based stem cell carrier for the repair of corneal alkali burns

BackgroundCorneal alkali burns can lead to ulceration, perforation, and even corneal blindness due to epithelial defects and extensive cell necrosis, resulting in poor healing outcomes. Previous studies have found that chitosan-based in situ hydrogel loaded with limbal epithelium stem cells (LESCs) has a certain reparative effect on corneal alkali burns. However, the inconsistent pore sizes of the carriers and low cell loading rates have resulted in suboptimal repair outcomes. In this study, 4D bioprinting technology was used to prepare a chitosan-based thermosensitive gel carrier (4D-CTH) with uniform pore size and adjustable shape to improve the transfer capacity of LESCs.MethodsPrepare solutions of chitosan acetate, carboxymethyl chitosan, and β-glycerophosphate sodium at specific concentrations, and mix them in certain proportions to create a pore-size uniform scaffold using 4D bioprinting technology. Extract and culture rat LESCs (rLESCs) in vitro, perform immunofluorescence experiments to observe the positivity rate of deltaNp63 cells for cell identification. Conduct a series of experiments to validate the cell compatibility of 4D-CTH, including CCK-8 assay to assess cell toxicity, scratch assay to evaluate the effect of 4D-CTH on rLESCs migration, and Calcein-AM/PI cell staining experiment to examine the impact of 4D-CTH on rLESCs proliferation and morphology. Establish a severe alkali burn model in rat corneas, transplant rLESCs onto the injured cornea using 4D-CTH, periodically observe corneal opacity and neovascularization using a slit lamp, and evaluate epithelial healing by fluorescein sodium staining. Assess the therapeutic effect 4D-CTH-loaded rLESCs on corneal alkali burn through histological evaluation of corneal tissue paraffin sections stained with hematoxylin and eosin, as well as immunofluorescence staining of frozen sections.ResultsUsing the 4D-CTH, rLESCs were transferred to the alkali burn wounds of rats. Compared with the traditional treatment group (chitosan in situ hydrogel encapsulating rLESCs), the 4D-CTH-rLESC group had significantly higher repair efficiency of corneal injury, such as lower corneal opacity score (1.2 ± 0.4472 vs 0.4 ± 0.5477, p < 0.05) and neovascularization score (5.5 ± 1.118 vs 2.6 ± 0.9618, p < 0.01), and significantly higher corneal epithelial wound healing rate (72.09 ± 3.568% vs 86.60 ± 5.004%, p < 0.01).ConclusionIn summary, the corneas of the 4D-CTH-rLESC treatment group were similar to the normal corneas and had a complete corneal structure. These findings suggested that LESCs encapsulated by 4D-CTH significantly accelerated corneal wound healing after alkali burn and can be considered as a rapid and effective method for treating epithelial defects.Graphical abstract

Macromolecular carrier with long retention and body-temperature triggered nitric oxide release for corneal alkali burn therapy via leptin-related signaling

Corneal injuries, such as alkali burn, are a common ocular trauma worldwide and usually cause corneal opacification and even loss of sight, if without timely treatments. Eye drops have long been regarded as the best media for treating ocular surface diseases. However, their effectiveness was seriously dampened by natural self-cleaning mechanism of the eye. Herein, we designed and prepared polyamino acid-based poly-S-nitrosothiols (PGlu-TEPA-SNAP) as long-acting eye drops to treat corneal alkali burns. The cationic polymeric NO donor demonstrated good retention on the negatively charged surface of cornea without causing obvious biotoxicity. Meanwhile, the polymer can release NO in a temperature-dependent manner, by remaining relatively stable at 4 ℃ and 25 ℃, while rapidly releasing NO at around 35 ℃. In vivo study proved that the eye-drop with proper concentration effectively mitigated alkali-induced corneal damage in mice, via leptin related STAT3/MAPK/AKT signaling pathway. It selectively promoted epithelium regeneration without inducing neovascularization by utilization of the difference in cell sensitivity towards NO. Overall, the combined strategy of temperature-dependent drug release and strong retention of carriers can indeed fasten the healing of damaged cornea. It may serve as an inspiration for future NO or leptin-based work for ocular surface therapy.

Endogenous TSG-6 modulates corneal inflammation following chemical injury

PurposeTumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) is upregulated in various pathophysiological contexts, where it has a diverse repertoire of immunoregulatory functions. Herein, we investigated the expression and function of TSG-6 during corneal homeostasis and after injury. MethodsHuman corneas, eyeballs from BALB/c (TSG-6+/+), TSG-6+/− and TSG-6−/− mice, human immortalized corneal epithelial cells and murine corneal epithelial progenitor cells were prepared for immunostaining and real time PCR analysis of endogenous expression of TSG-6. Mice were subjected to unilateral corneal debridement or alkali burn (AB) injuries and wound healing assessed over time using fluorescein stain, in vivo confocal microscopy and histology. ResultsTSG-6 is endogenously expressed in the human and mouse cornea and established corneal epithelial cell lines and is upregulated after injury. A loss of TSG-6 has no structural and functional effect in the cornea during homeostasis. No differences were noted in the rate of corneal epithelial wound closure between BALB/c, TSG-6+/− and TSG-6−/− mice. TSG-6−/− mice presented decreased inflammatory response within the first 24 h of injury and accelerated corneal wound healing following AB when compared to control mice. ConclusionTSG-6 is endogenously expressed in the cornea and upregulated after injury where it propagates the inflammatory response following chemical injury.

Exploring the Role of Lycium barbarum Polysaccharide in Corneal Injury Repair and Investigating the Relevant Mechanisms through In Vivo and In Vitro Experiments.

Lycium barbarum polysaccharide (LBP) is the main active component of Fructus Lycii, exhibiting various biological activities. This study aims to explore the protective effects of LBP on human corneal epithelial cells (HCEC) and a rat corneal injury model. Potential target points for LBP improving corneal injury repair were screened from public databases, and functional and pathway enrichment analyses of core targets were conducted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Rat corneal alkali burns and HCEC oxidative stress injury models were established, and the results were validated through slit lamp examination, HE staining, TUNEL assay, immunofluorescence, CCK-8 assay, flow cytometry, scratch assay, and qRT-PCR methods. In the context of database retrieval, identification of 10 LBP monosaccharide components and 50 corneal injury repair-related targets was achieved. KEGG pathway analysis suggested that LBP might regulate the IL-17 and TNF signaling pathways through targets such as JUN, CASP3, and MMP9, thereby improving corneal damage. In vivo and in vitro experimental results indicated that LBP could reduce the increase of inflammation index scores (p < 0.05), inflammatory cell density (p < 0.01), TUNEL-positive cells (p < 0.01), corneal opacity scores (p < 0.01), and expression of corneal stromal fibrosis-related proteins α-SMA, FN, and COL (p < 0.01) caused by chemical damage to rat corneas. LBP inhibited oxidative stress-induced decreases in cell viability (p < 0.001) and migration healing ability (p < 0.01) in HCECs, reducing apoptosis rates (p < 0.001), ROS levels (p < 0.001), and the expression of inflammatory factors TNF-α and IL-6 (p < 0.01). qRT-PCR results demonstrated that LBP intervention decreased the mRNA levels of JUN, CASP3, and MMP9 in H2O2-induced alkaline-burned corneas and HCECs (p < 0.01).The integrated results from network pharmacology and validation experiments suggest that the inhibitory effects of LBP on apoptosis, inflammation, and fibrosis after corneal injury may be achieved through the suppression of the TNF and IL-17 signaling pathways mediated by JUN, CASP3, and MMP9.