Lycium barbarum Polysaccharides Protect Rat Corneal Epithelial Cells against Ultraviolet B-Induced Apoptosis by Attenuating the Mitochondrial Pathway and Inhibiting JNK Phosphorylation

Construction of Dome-Shaped 3D Corneal Epithelial Tissue Models Based on Eyeball-Shaped Gel Microspheres

By overcoming interspecies differences and mimicking the in vivo microenvironment, three-dimensional (3D) in vitro corneal models have become a significant novel tool in contemporary ophthalmic disease research. However, existing 3D corneal models struggle to replicate the actual human corneal environment, especially the dome-shaped physiological structure with adjustable curvature. Addressing these challenges, this study introduces a straightforward method for fabricating collagen/chitosan-alginate eyeball-shaped gel microspheres with a Janus structure via a two-phase aqueous system, used subsequently to construct in vitro 3D corneal epithelial tissue models. By adjusting the diameter ratio of collagen/chitosan to alginate droplets, we can create eyeball-shaped gel microspheres with varying curvatures. Human corneal epithelial cells were seeded on the surfaces of these microspheres, leading to the formation of in vitro 3D corneal epithelial tissues characterized by dome-like multilayers and tight junctions. Additionally, the model demonstrated responsiveness to UVB exposure through the secretion of reactive oxygen species (ROS) and proinflammatory factors. Therefore, we believe that in vitro 3D corneal epithelial tissue models with dome-shaped structures hold significant potential for advancing ophthalmic research.

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.

Portulaca oleracea L. Polysaccharide Inhibits Porcine Rotavirus In Vitro

Diarrhea is one of the most common causes of death in young piglets. Porcine rotavirus (PoRV) belongs to the genus Rotavirus within the family Reoviridae, and is considered to be the primary pathogen causing diarrhea in piglets. Portulaca oleracea L. (POL) has been reported to alleviate diarrhea and viral infections. However, the antiviral effect of Portulaca oleracea L. polysaccharide (POL-P), an active component of POL, on PoRV infection remains unclear. This study demonstrated that the safe concentration range of POL-P in IPEC-J2 cells is 0-400 μg/mL. POL-P (400 μg/mL) effectively inhibits PoRV infection in IPEC-J2 cells, reducing the expression of rotavirus VP6 protein, mRNA and virus titer. Furthermore, on the basis of viral life cycle analysis, we showed that POL-P can decrease the expression of PoRV VP6 protein, mRNA, and virus titer during the internalization and replication stages of PoRV. POL-P exerts antiviral effects by increasing IFN-α expression and decreasing the expression levels of TNF-α, IL-6, and IL-10 inflammatory factors. Overall, our study found that POL-P is a promising candidate for anti-PoRV drugs.

Recent Advancements in Molecular Therapeutics for Corneal Scar Treatment

The process of corneal wound healing is complex and induces scar formation. Corneal scarring is a leading cause of blindness worldwide. The fibrotic healing of a major ocular wound disrupts the highly organized fibrillar collagen arrangement of the corneal stroma, rendering it opaque. The process of regaining this organized extracellular matrix (ECM) arrangement of the stromal layer to restore corneal transparency is complicated. The surface retention capacity of ocular drugs is poor, and there is a large gap between suitable corneal donors and clinical requirements. Therefore, a more efficient way of treating corneal scarring is needed. The eight major classes of interventions targeted as therapeutic tools for healing scarred corneas include those based on exosomes, targeted gene therapy, microRNAs, recombinant viral vectors, histone deacetylase inhibitors, bioactive molecules, growth factors, and nanotechnology. This review highlights the recent advancements in molecular therapeutics to restore a cornea without scarring. It also provides a scope to overcome the limitations of present studies and perform robust clinical research using these strategies.

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.

Cytoprotective Effects of Water Soluble Dihydropyrimidinthione Derivative Against UV-B Induced Human Corneal Epithelial Cell Photodamage

Excessive UV-B exposure is well known to be a risk factor for corneal phototoxicity including direct DNA damage and disturbances in the antioxidant balance. Here, we showed a successful synthesis of a water-soluble and biocompatible small molecule DHPM 1 with dihydropyrimidinthione skeleton, which could effectively protect human corneal epithelial (HCE-2) cells from UV-B damage. In separate experiments, DHPM 1 absorbed UV-B rays and exhibited scavenging activity against intracellular ROS induced by UV-B radiation, thereby reducing the levels of DNA fragmentation. Additionally, UV-B exposure increased the expression of cleaved caspase-3, as well as the ratio of Bax/Bcl-2 at protein levels, while pretreatment with DHPM 1 significantly reversed these changes. To the best of our knowledge, this is the first report of a study based on dihydropyrimidinthione derivatives to develop a promising eye drops, which may well find extensive applications in UV-B caused corneal damage.

Sirt1 attenuates diabetic keratopathy by regulating the endoplasmic reticulum stress pathway

AIMS

The objectives of this study were to explore physiological and pathological changes in the corneas of diabetic rats by intervening in the expression of silent information regulator 1 (Sirt1) and to investigate whether Sirt1 can regulate the activation of endoplasmic reticulum stress (ERS) while influencing corneal epithelial cell apoptosis under high glucose conditions.

MATERIALS AND METHODS

Using 8-week old Sprague-Dawley rats, we established a model of type 1 diabetes, with or without Sirt1 intervention. Clinical evaluation was performed once per week. Primary rat corneal epithelial cells (RCECs) were cultured by combining Sirt1 intervention under high glucose conditions. Generation of reactive oxygen species (ROS), apoptosis, and the expression of Sirt1 and ERS-related proteins were evaluated in rat corneal tissues and RCECs.

KEY FINDINGS

During the intervention, clinical evaluation of the ocular surface, ROS generation, apoptosis, and protein expression of ERS-related proteins in corneal tissue and cultured RCECs were altered with Sirt1expression levels.

SIGNIFICANCE

Sirt1 expression influences the pathological progression of diabetic keratopathy, plays an important role in regulating the ERS pathway, and decreases corneal epithelial cell apoptosis.

Lycium barbarum Polysaccharide Suppresses Expression of Fibrotic Proteins in Primary Human Corneal Fibroblasts

(1) Objective: To study the anti-fibrotic effects of Lycium barbarum polysaccharides (LBP) on corneal stromal fibroblasts and assess LBP’s effect on cell viability. (2) Methods: Primary human corneal keratocytes of passage 3 to 6 were used for all experiments. Cells are pretreated with LBP solution for 24 h and then transforming growth factor beta 1 (TGFβ1) for 48 h and collected for experiments. Fibrotic protein analysis was performed using immunofluorescence and Western blot. The effect of LBP on cell viability was assessed using the MTS assay. (3) Results: LBP significantly reduced the expression of fibrotic proteins, including α-SMA and extracellular matrix proteins (collagen type I and III). LBP significantly decreased the viability of myofibroblasts but not the fibroblasts. Conclusions: In this study, LBP was effective in the prevention of fibrosis gene expression. Further studies to assess the underlying mechanism and pharmacological properties will facilitate the formation of a topical LBP solution for in vivo studies.

Systematic Review on Therapeutic Strategies to Minimize Corneal Stromal Scarring After Injury

OBJECTIVES

To evaluate recent studies on available and experimental therapies in preventing or minimizing corneal stromal scarring after injury.

METHODS

We performed an Entrez PubMed literature search using keywords "cornea," "scarring," "haze," "opacity," "ulcer," "treatments," "therapies," "treatment complications," and "pathophysiology" resulting in 390 articles of which 12 were analyzed after filtering, based on English language and publication within 8 years, and curation for relevance by the authors.

RESULTS

The 12 articles selected included four randomized control trials (RCTs) (two were double-blinded placebo-controlled RCTs, one was a prospective partially masked RCT, and one was an open-label RCT), two retrospective observational studies, and six laboratory-based studies including two studies having in vivo and in vitro experiments, one was in vivo study, one was ex vivo study, and the last two were in vitro studies. The current mainstay for preventing or minimizing corneal scarring involves the use of topical corticosteroids and local application of mitomycin C. However, supportive evidence for their use in clinical practice from well-designed RCTs is lacking. Laboratory studies on topical rosiglitazone therapy, vitamin C prophylaxis, gene therapy, and stem cell therapy have shown promising results but have yet to be translated to clinical research.

CONCLUSION

There is a need for more robust randomized controlled trials to support treatments using topical corticosteroids and mitomycin C. Furthermore, their clinical efficacy and safety profile should be compared with new treatments that have shown promising results in the laboratory setting. Ultimately, the goal should be to personalize cornea scarring treatment according to the most effective treatment for the specific underlying pathology.

Protective effects of lycium barbarum polysaccharides on blood-retinal barrier via ROCK1 pathway in diabetic rats

Lycium barbarum polysaccharides (LBP) is commonly known as a traditional Chinese medicine, which has protective effects against diabetic complications in clinic, such as diabetic retinopathy (DR). Previous studies have revealed that Rho/ROCK pathway play an important role in DR development. However, the mechanism between LBP and DR remains unknown. This study aims to explore the clear mechanism of the protective effect of LBP in diabetic retinopathy. In this study, streptozocin (STZ, 45 mg/kg) was administered for diabetic rats modeling. Weight, blood glucose levels and blood lipid were measured to assess the metabolic changes by LBP on diabetic rats. Evans blue (EB) extravasation was determined to assess blood-retinal barrier (BRB) disruption. Hematoxylin and Eosin (HE) staining and immunohistochemistry assay were applied for retina morphology exploration. The membranous disks of retina were examined by transmission electron microscope. Further, high glucose condition was induced in choroidal-retinal endothelial cells (RF/6A). Western blotting was performed for P-Occludin, ROCK1 and P-MLC protein expression. The results indicated that the blood glucose levels, blood lipid and EB infiltration capacity were decreased while the weight was increased in LBP-treated diabetic rats compared with model rats. Moreover, LBP could thicken the overall retina, prevent the disturbance of photoreceptor cell membranous disks and inhibit pathological angiogenesis in diabetes. In addition, the decreased expression of P-Occludin and increased expression of RhoA-associated protein kinase (ROCK) or phosphorylated myosin light chain (P-MLC) were observed in retinal tissue of diabetic rats and high glucose induced by RF/6A cells, which could be rescued by LBP and/or Fasudil. LBP has the protective effects on blood-retinal barrier by regulating the Rho/ROCK signaling pathway in diabetic rats. LBP may be served as a Rho/ROCK inhibitor for the treatment of DR.

Effects of HGF and KGF gene silencing on vascular endothelial growth factor and its receptors in rat ultraviolet radiation‑induced corneal neovascularization

Hepatocyte growth factor (HGF) and keratinocyte growth factor (KGF), two paracrine growth factors, modulate corneal epithelial cell metabolism, apoptosis and survival. Vascular endothelial growth factor (VEGF) serves as a proangiogenic factor in corneal neovascularization (CNV), which is a major cause of vision impairment and corneal blindness. The aim of the present study was to evaluate the ability of HGF and KGF to influence VEGF and its receptor, kinase insert domain receptor (Flk‑1) in corneal injury and CNV in rats induced by ultraviolet radiation (UVR). An UVR‑induced corneal injury rat model was successfully established to characterize the expression patterns of KGF, HGF, VEGF and Flk‑1 in corneal tissues. Corneal epithelial cells were extracted and treated with small interfering RNAs (siRNAs) targeting KGF, HGF or both (si‑KGF, si‑HGF or si‑HGF/KGF). The effects of HGF and KGF were examined through detection of the expression of KGF, HGF, VEGF and Flk‑1, and the evaluation of cell proliferation, cell cycle and cell apoptosis. The expression levels of KGF, HGF, VEGF and Flk‑1 in corneal tissues were increased in the rat model. In the cell experiments, the transfection of si‑HGF/KGF resulted in reductions in VEGF, Flk‑1, KGF and HGF. In addition, decreased cell proliferation and elevated cell apoptosis were found in the corneal epithelial cells from the rat model following KGF and HGF gene silencing. Taken together, these findings suggest that HGF and KGF gene silencing inhibits UVR‑induced corneal epithelial proliferation and CNV and may function as novel targets for corneal wound healing.

A Systematic Review of Potential Therapeutic Use of Lycium Barbarum Polysaccharides in Disease

Objective

To evaluate the effect of Lycium barbarum polysaccharides in the treatment and/or prevention of diseases of different etiologies and systems.

Methods

We performed an Entrez PubMed literature search using keywords “lycium”, “barbarum”, “polysaccharides”, “anti-fibrotic”, “anti-apoptotic”, “anti-oxidizing”, “anti-aging”, “neuroprotection”, “metabolism”, “diabetes”, “hyperlipidemia”, “neuroprotection”, and “immunomodulation” on the 14^th of August 2018, resulting in 207 papers, of which 20 were chosen after filtering for ‘English language' and ‘published within 10 years' as well as curation for relevance by the authors.

Results

The 20 selected papers included 2 randomized control trials (1 double-blinded RCT and 1 double-blinded placebo-controlled RCT), 11 in vivo studies, 5 in vitro studies, 1 study with both in vivo and in vitro results, and 1 chemical study. There is good evidence from existing studies on the antifibrotic, antioxidizing, neuroprotective, anticancer, and anti-inflammatory effects of Lycium barbarum polysaccharides. However, there is a need for further studies in the form of large-scale clinical trials to support its use in humans. There is also significant potential for LBP as a safe and effective topical treatment in ocular surface diseases, owing to promising in vitro results and a lack of demonstrated toxic effects to corneal epithelial cells.

Conclusion

Results from existing studies suggest that LBP is a promising therapeutic agent, particularly in the management of liver disease, hyperlipidemia, and diabetes. One major limitation of current research is a lack of standardization and quality control for the LBP used. The availability of research-grade LBP will inevitably promote future research in this field worldwide.

Purification, characterization and anti-tumor activities of polysaccharides extracted from wild Russula griseocarnosa

The anti-tumor activity of a novel polysaccharide, PRG1-1, obtained from Russula griseocarnosa sporocarp was investigated in this paper. PRG1-1 has a molecular weight of 630kDa and was extracted and purified using DEAE-cellulose and gel filtration chromatography from crude polysaccharide extract of R. griseocarnosa sporocarp. PRG1-1 was composed of glucose, galactose, mannose, xylose and fructose, in a molar ratio of 66.5:29.2:3.17: 0.663:0.447, respectively. Purified PRG1-1 significantly reduced cell viability, increased the production of lactate dehydrogenase (LDH) and reactive oxygen species (ROS), and enhanced the apoptotic rate in HeLa and SiHa cells. Furthermore, after 24h of PRG1-1 exposure the expression levels of cleaved PARP and caspase-3 were increased and mitochondrial cytochrome c was induced to release to the cytosol. Collectively, our results suggested that the cytotoxicity effects of PRG1-1 on human cervical carcinoma are associated with the apoptotic pathway. These data indicate the promising potential of bioactive PRG1-1 as natural agent to inhibit tumor cell proliferation in the treatment of cervical carcinoma.