PLGA nanoparticles containing Lingzhi extracts rescue corneal epithelial cells from oxidative damage.

Oxidative stress-related ocular surface epithelial damage can be initiated by ambient oxygen, UV radiation, and chemical burns. The oxidative damage to cornea can lead to inflammation and even vision loss. Lingzhi (Ganoderma lucidum) is a Chinese herbal drug and has been shown to prevent chronic diseases in clinical practices and has been proven to possess anti-oxidative and anti-inflammatory properties. In the study, we prepared poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) as a sustained drug release system of Lingzhi (LZH) to improve bioavailability. The particle size of developed NPs containing LZH (LZH-NPs) was ~184 nm with narrow size distribution. The results of cellular uptake revealed that using NPs as a drug delivery system could significantly increases the intracellular retention time. The results of the cell viability and chemiluminescence assay revealed that 5 µg/ml of LZH-NPs might be the threshold concentration for cultivation of corneal epithelial cells. After treating LZH-NPs in oxidative damaged cells, the results showed that the inflammation-related gene expression and DNA fragmentation level were both significantly decreased. Post-treatment of LZH-NPs in damaged corneal epithelial cells could increase the cell survival rate. In the rabbit corneal alkali burn model, topical instillation of LZH-NPs could promote corneal wound healing and decrease the inflammation. These results suggest that LZH-NPs may have the potential to treat ocular surface diseases caused by oxidative stress.

Cucurbita argyrosperma Seed Extracts Attenuate Angiogenesis in a Corneal Chemical Burn Model.

Severe corneal inflammation produces opacity or even perforation, scarring, and angiogenesis, resulting in blindness. In this study, we used the cornea to examine the effect of new anti-angiogenic chemopreventive agents. We researched the anti-angiogenic effect of two extracts, methanol (Met) and hexane (Hex), from the seed of Cucurbita argyrosperma, on inflamed corneas. The corneas of Wistar rats were alkali-injured and treated intragastrically for seven successive days. We evaluated: opacity score, corneal neovascularization (CNV) area, re-epithelialization percentage, and histological changes. Also, we assessed the inflammatory (cyclooxigenase-2, nuclear factor-kappaB, and interleukin-1ß) and angiogenic (vascular endothelial growth factor A, VEGF-A; -receptor 1, VEGFR1; and -receptor 2, VEGFR2) markers. Levels of Cox-2, Il-1ß, and Vegf-a mRNA were also determined. After treatment, we observed a reduction in corneal edema, with lower opacity scores and cell infiltration compared to untreated rats. Treatment also accelerated wound healing and decreased the CNV area. The staining of inflammatory and angiogenic factors was significantly decreased and related to a down-expression of Cox-2, Il-1ß, and Vegf. These results suggest that intake of C. argyrosperma seed has the potential to attenuate the angiogenesis secondary to inflammation in corneal chemical damage.

Comparative proteomic analysis of amnion membrane transplantation and cross-linking treatments in an experimental alkali injury model.

PURPOSE: In this study, by using a two-dimensional (2D) electrophoresis-based experimental approach, we aimed at understanding the nature of alkali injuries and the underlying mechanisms. A secondary aim was to compare the effects of cross-linking (CXL) and amnion membrane transplantation (AMT) on corneal protein compositions at the end of the early repair phase after injured with alkali. METHOD: The right corneas of 24 rabbits were injured with a 1 N solution of NaOH. Groups were formed based on the adjuvant therapies as (1) healthy group, (2) control group, (3) CXL group, (4) AMT group. In addition to the therapies, a conventional medical treatment was applied to all groups. Left eyes were used as within-subject healthy corneas (1). The corneas were excised at day 21, and a comparative proteomic analysis was performed using 2D gel electrophoresis coupled with MALDI-TOF/TOF. RESULT: 2D gel electrophoresis revealed the presence seven protein spots whose abundance changed among the groups. Those proteins were SH3 domain-binding protein, plant homeodomain finger protein 23, S100 calcium binding protein A-11(S100 A11), keratin type 2 cytoskeletal 1 and 2, transketolase and glyceraldehyde 3-phosphate dehydrogenase. Ingenuity pathway analysis predicted that the observed changes may be linked to a central metabolic pathway, transforming growth factor beta 1. Canonical pathway analysis focused our attention to two different pathways, namely nicotinamide adenine dinucleotide repair pathway and non-oxidative branch of pentose phosphate pathway. CONCLUSION: Our results shed some light onto the molecular mechanisms affected by alkali injury and adjuvant treatments. Further research is needed to propose medically significant target molecules that may be used for novel drug developments for alkali injury.

Therapeutic effects of zerumbone in an alkali-burned corneal wound healing model.

Cornea is an avascular transparent tissue. Ocular trauma caused by a corneal alkali burn induces corneal neovascularization (CNV), inflammation, and fibrosis, leading to vision loss. The purpose of this study was to examine the effects of Zerumbone (ZER) on corneal wound healing caused by alkali burns in mice. CNV was induced by alkali-burn injury in BALB/C female mice. Topical ZER (three times per day, 3µl each time, at concentrations of 5, 15, and 30µM) was applied to treat alkali-burned mouse corneas for 14 consecutive days. Histopathologically, ZER treatment suppressed alkali burn-induced CNV and decreased corneal epithelial defects induced by alkali burns. Corneal tissue treated with ZER showed reduced mRNA levels of pro-angiogenic genes, including vascular endothelial growth factor, matrix metalloproteinase-2 and 9, and pro-fibrotic factors such as alpha smooth muscle actin and transforming growth factor-1 and 2. Immunohistochemical analysis demonstrated that the infiltration of F4/80 and/or CCR2 positive cells was significantly decreased in ZER-treated corneas. ZER markedly inhibited the mRNA and protein levels of monocyte chemoattractant protein-1 (MCP-1) in human corneal fibroblasts and murine peritoneal macrophages. Immunoblot analysis revealed that ZER decreased the activation of signal transducer and activator of transcription 3 (STAT3), with consequent reduction of MCP-1 production by these cells. In conclusion, topical administration of ZER accelerated corneal wound healing by inhibition of STAT3 and MCP-1 production.

Mechanisms of Retinal Damage after Ocular Alkali Burns.

Alkali burns to the eye constitute a leading cause of worldwide blindness. In recent case series, corneal transplantation revealed unexpected damage to the retina and optic nerve in chemically burned eyes. We investigated the physical, biochemical, and immunological components of retinal injury after alkali burn and explored a novel neuroprotective regimen suitable for prompt administration in emergency departments. Thus, in vivo pH, oxygen, and oxidation reduction measurements were performed in the anterior and posterior segment of mouse and rabbit eyes using implantable microsensors. Tissue inflammation was assessed by immunohistochemistry and flow cytometry. The experiments confirmed that the retinal damage is not mediated by direct effect of the alkali, which is effectively buffered by the anterior segment. Rather, pH, oxygen, and oxidation reduction changes were restricted to the cornea and the anterior chamber, where they caused profound uveal inflammation and release of proinflammatory cytokines. The latter rapidly diffuse to the posterior segment, triggering retinal damage. Tumor necrosis factor-α was identified as a key proinflammatory mediator of retinal ganglion cell death. Blockade, by either monoclonal antibody or tumor necrosis factor receptor gene knockout, reduced inflammation and retinal ganglion cell loss. Intraocular pressure elevation was not observed in experimental alkali burns. These findings illuminate the mechanism by which alkali burns cause retinal damage and may have importance in designing therapies for retinal protection.

Triptolide Suppresses Alkali Burn-Induced Corneal Angiogenesis Along with a Downregulation of VEGFA and VEGFC Expression.

Triptolide (TPL) is an active compound extracted from a Chinese herbal medicine tripterygium wilfordii Hook. f. (Celastraceae), which has been used as an anti-inflammatory drug for years. It also inhibits the growth and proliferation of different types of cancer cells. The inhibitory effect of TPL on angiogenesis after chemical-induced corneal inflammation was studied in vivo. The effects of TPL on the proliferation, apoptosis, migration, and tube formation of rat aortic endothelial cells (RAECs) were studied in vitro. Cell proliferation and apoptosis were measured by MTT assay and flow cytometry, respectively. Migration was analyzed using the scratch wound healing assay and transwell assay. Tube formation assay was used to examine angiogenesis. Real-time PCR and Western blot were used to determine the expression of vascular endothelial growth factor A (VEGFA) and VEGFC. To study the in vivo effects of TPL, the mouse model of alkali burn-induced corneal angiogenesis was used. The angiogenesis was analyzed by determining the density of the newly generated blood vessels in corneas. We found that TPL induced apoptosis and inhibited the proliferation of RAECs in a dose-dependent manner. TPL inhibited migration and tube formation of RAECs and decreased the expression of VEGFA and VEGFC in vitro. Furthermore, TPL suppressed alkali burn-induced corneal angiogenesis and inhibited the expression of VEGFA and VEGFC in corneas in vivo. In conclusion, topical TPL as a pharmacological agent has the ability to reduce angiogenesis in cornea and may have clinical indications for the treatment of corneal angiogenesis diseases which have to be further explored. Anat Rec, 300:1348-1355, 2017. © 2017 Wiley Periodicals, Inc.

Use of natural antioxidants for the correction of changes in general and local parameters of lipid peroxidation and antioxidant defense system during experimental eye burn.

The effect of natural antioxidants in grade III chemical eye burn was studied in experiments on rabbits at various stages of burn disease. The use of histochrome, Gingko Biloba, and diquertin in combination with complex drug therapy decelerated the decrease in the antioxidant potential of tear fluid and blood plasma. This treatment was also followed by a decrease in the concentration of end products of free radical oxidation.

Effect of natural antioxidants on antioxidant activity and lipid peroxidation in eye tissue of rabbits with chemical burns.

Chemical eye burns were accompanied by free radical oxidation of lipids and dysfunction of the antioxidant protection system. The decrease in antioxidant activity of blood plasma reflected a generalized type of these processes. The concentration of thiobarbituric acid-reactive substances increased in blood plasma from rabbits with eye burns. The severity of disturbances was maximum at the stage of trophic disorders. Combination therapy with antioxidants and standard pharmaceuticals effectively inhibited lipid peroxidation in eye tissue of experimental animals.

Effect of gefarnate on the ocular surface in squirrel monkeys.

PURPOSE: To investigate the ability of gefarnate (geranyl farnesylacetate) to stimulate goblet cell function in the primate eye after a mild alkali injury of the tarsal conjunctiva. METHODS: A bilateral injury was created on the conjunctival surface of the lower eye lid of squirrel monkeys by means of a 30-second application of a 4-mm diameter piece of filter paper wetted with 0.5% NaOH. Gefarnate drops (1%) were administered to one eye of each monkey and vehicle alone in the contralateral eye six times a day, 5 days a week for 4 weeks. Slit-lamp biomicroscopy, impression cytology staining of the ocular surface, fluorescein and rose bengal staining, and Western blot for mucin were performed before injury and weekly thereafter. Light microscopy was used to evaluate the lower conjunctiva. RESULTS: Topical application of gefarnate was not associated with any adverse ocular surface effects. Goblet cell repopulation after injury was significantly greater in the gefarnate-treated eyes compared with the vehicle-treated eyes. In the gefarnate-treated eyes, tear mucin content was significantly greater at 1 week after injury. Fluorescein staining was significantly reduced at 3 weeks after injury, and rose bengal staining was significantly reduced in the area of the wound at 2 weeks in the gefarnate-treated eyes compared with the vehicle-treated eyes; at other times, conjunctival staining in the two groups of eyes was not significantly different. CONCLUSIONS: Gefarnate promotes goblet cell repopulation and increases mucin production after a conjunctival injury. No adverse affects of the treatment were found. Thus, this agent may be useful in conditions that diminish goblet cell function.

[Experimental validation of the use of RNA hydrolysate (ENKAD) in chemical burns of the cornea]. / Eksperimental'noe obosnovanie primeneniia gidrolizata RNK (ENKAD) pri khimicheskikh ozhogakh rogovitsy.

The influence of ENKAD on the course of a severe alkaline burn of the cornea was studied in 158 rabbits (316 eyes). Cytochemically, regularity in correlations of separate amino acids: cystin, cysteine, arginine and glutaminic acid in cellular proteins of the intact cornea was established and their disorder in dynamics of the burn process is shown. Comparative assessment of therapeutic effectiveness of ultrasound, applications, subconjunctival injections and phonophoresis of ENKAD has shown that a combined usage of ultrasound and ENKAD has the most expressed positive action on the course of the burn process of the corneal burn, such as acceleration of corneal epithelialization that accomplished, on the average, by the 9.3 +/- 0.3 day (in the control--by the 20.8 +/- 1.8 day), rapid disappearance of its perifocal edema--11.05 +/- 0.7 (in the control - 29.7 +/- 1.1) day, better outcomes after the burn (in 37.5% of cases superficial limited opacifications were formed, in the control--in 7.1%). One of the factors of therapeutic action of ENKAD phonophoresis is its normalizing influence on disturbed correlation of amino acids in proteins. The results obtained allow to recommend to include ENKAD phonophoresis into a complex treatment of patients with eye burns.