Experimental eye research最新文献

One of the main causes of corneal blindness is corneal alkali burn, which can also result in serious side effects such as limbal stem cell deficit, corneal perforation, and permanent epithelial abnormalities. This study set out to investigate the therapeutic potential of ADMSCs and BMMSCs for the reconstruction of the corneal surface after chemical alkali burn. Twelve adult rabbits were divided equally into four groups. Each rabbit in the other groups had a chemical alkali burn applied to their right eye using 6 mm-wide NaoH soaked filter paper, while the negative control group had no intervention. All groups except negative control group received topical and subconjunctival injections. Group I (Negative control) received no therapy, whereas Group II received an injection of phosphate-buffered saline as the positive control. Group III received 1 mL of ADMSCs, while Group IV received 1 mL of BMMSCs. After 4 weeks, the corneal tissue underwent morphological, histological, immunohistochemical examination and gene expression. The ocular tissue underwent histopathological examination revealed re-epithelialization and nearly normal architecture in the BMMSC-treated group. The injured cornea treated with ADMSCs showed partial repair of the anterior epithelium, in addition to inflammatory cells infiltration. An immunohistochemical analysis revealed that, compared to ADMSCs and positive control groups, the majority of the stromal cells in the cornea treated by BMMSCs exhibited robust positive expression of vimentin and Ki67. BMMSCs exhibited considerably higher levels of gene expression for corneal indicators, such as keratin 12 and connexin 43, in comparison to other groups. In treating a corneal chemical burn, this study shows that MSCs produced from bone marrow and adipose tissue effectively reduce tissue inflammation, enhance corneal tissue repair, and stimulate cell renewal, with BMMSCs showing better outcomes.

Tear inflammatory cytokines are a novel biomarker studied in a range of ocular surface diseases, periorbital and orbital conditions. This single-centre prospective study between 2022 and 2024 aims to characterise tear cytokine profiles (Interleukin-1β [IL-1β], IL-2, IL-6, Interferon-γ [IFN-γ] and Tumour Necrosis Factor-α [TNF- α]) in orbital inflammatory disease (OID). OID patients had pre-treatment tear collection via micropipette, and cytokine analysis via multiplex bead array analysis. Thirteen healthy controls with no prior ophthalmic history were enrolled for comparison. Eighteen tear specimens from seventeen OID patients (6 males; mean age: 52.1 ± 17.1-years-old), with one repeat tear sample taken for recurrent contralateral orbital inflammation. Diagnoses included non-specific orbital inflammation (47.1%), IgG4-related orbital disease (17.6%), orbital granulomatosis with polyangiitis (5.9%), giant cell arteritis (5.9%), herpes zoster ophthalmicus with orbital apex inflammation (5.9%), viral dacryoadenitis (5.9%), bacterial dacryoadenitis (5.9%) and orbital inflammation of uncertain cause (5.9%). Overall, OID patients, and specifically those with dacryoadenitis, had greater IL-6 levels compared to controls (P = 0.038 and 0.002, respectively). OID with dacryoadenitis had higher IL-1β levels compared to those without (P = 0.029). Higher IL-6 levels were observed in idiopathic dacryoadenitis compared to healthy controls (P = 0.008, respectively). There is significant variability in tear inflammatory cytokines profiles observed in OID. IL-1β and IL-6 levels may be non-specific markers of dacryoadenitis and may be particularly elevated in idiopathic dacryoadenitis. Tear cytokines may be affected by severity, localisation and pattern of inflammation. The utility of tear cytokines in the monitoring and prognostication of OID remains to be elucidated.

Dry eye disease (DED) is a prevalent ophthalmic disease that affects millions of people worldwide. Iron overload and macrophage inflammation have been implicated in the development of murine DED, though the specific role of macrophages under iron overload conditions remains unclear. This study aimed to establish a novel iron overload-induced mouse model of DED and investigate macrophage involvement. The model was induced via intraperitoneal injection of D-glucoside iron. Results showed that macrophage depletion via clodronate liposomes (CL) significantly mitigated iron deposit, decreased ocular surface inflammation, improved tear production and restored the structure of ocular surface tissues. Furthermore, CL specifically targeted pro-inflammatory M1 macrophages and reduced levels of the inflammatory cytokines IL-1β, IL-6, and TNF-α, effectively alleviating symptoms of DED. In conclusion, this study characterized a novel iron overload-induced DED mouse model and demenstrated that macrophage depletion mitigated the pathological changes in ocular surface and lacrimal gland tissues caused by iron overload, suggesting potential therapeutic strategies for further investigation in the treatment of DED.

0.05% cyclosporine A eye drops is a kind of new medication for dry eye after corneal refractive surgeries. However, it is still unclear how this eye drops affect the healing process of corneal epithelial defects caused by operative procedures. In this vivo study, the effect of 0.05% cyclosporine A eye drops on the healing process of the corneal epithelium was assessed in a rat model featuring mechanically induced central corneal epithelial defects. These Sprague-Dawley rats were randomly divided into three groups, the 0.05% cyclosporine A eye drops group (CsA group), the 0.1% sodium hyaluronate eye drops group (HA group), and the model control group (MC group). The epithelial healing, tear secretion, epithelial microvilli, expression of apoptosis markers (TUNEL, p53, and bcl-2 proteins), inflammatory factors (IL-1β, TNF-α, and IL-6), and epidermal growth factor (EGF) were detected in the current study using corneal fluorescein sodium staining, phenol red thread test, transmission electron microscopy (TEM), immunofluorescence, and enzyme-linked immunosorbent assay (ELISA), respectively. Compared to the other two groups, lower expression of apoptosis markers and inflammatory factors were exhibited in the CsA group, along with its faster and better epithelial healing and higher tear secretion (P < 0.05). In conclusion, 0.05% cyclosporine A eye drops effectively promote the healing process for corneal epithelial defects in rats, potentially offering advantages for rapid corneal recovery after refractive surgical procedures.

Restricted oxygen supply in the aging eye may lead to hypoxic conditions in the outer retina and contribute not only to physiological aging but also to nonhereditary degenerative retinal diseases. To understand the hypoxic response of specific retinal cell types, we performed single-cell RNA sequencing of retinas isolated from mice exposed to hypoxia. Significantly upregulated expression of marker genes in hypoxic clusters confirmed a general transcriptional response to hypoxia. By focusing on the hypoxic response in photoreceptors, we identified and confirmed a kinesin motor protein (Kif4) that was specifically and strongly induced in hypoxic cones. In contrast, RNA-binding proteins Rbm3 and Cirbp were differentially expressed across clusters but demonstrated isoform switching in hypoxia. The resulting short variants of these gene transcripts are connected to epitranscriptomic regulation, a notion supported by the differential expression of writers, readers and erasers of m⁶A RNA methylations in the hypoxic retina. Our data indicate that retinal cells adapt to hypoxic conditions by adjusting their transcriptome at various levels including gene expression, alternative splicing and the epitranscriptome. Adaptational processes may be cell-type specific as exemplified by the cone-specific upregulation of Kif4 or general like alternative splicing of RNA binding proteins.

The corneal extracellular matrix is mainly composed of collagen fibers, proteoglycans (PGs), and glycosaminoglycans (GAGs). The present work was done to investigate the effect of GAGs on linear viscoelastic shear properties of human and porcine cornea. A clear understanding of structural functions of GAGs could result in the development of new intervention methods for diseased conditions that involve changes to the expression of GAGs/PGs. Here, we used keratanase II enzyme to deplete sulfated GAGs from porcine and human donor corneal disks. After quantifying the GAG content, collagen fiber diameter, and interfibrillar spacings of control and GAG-depleted specimens using the Blyscan assay and transmission electron microscopy, we performed torsional rheometry to determine their shear properties at different levels of axial strain. We found that the GAG content of control human (52.35 ± 3.40 μg/mg dry tissue) and porcine cornea (48.59 ± 7.79 μg/mg dry tissue) significantly reduced following keratanase II enzyme treatment. Moreover, we observed that the diameter of collagen fibers (28.78 ± 2.33 nm) and interfibrillar spacing (45.93 ± 2.33 nm) of human specimens were significantly smaller than the collagen fiber diameter (34.77 ± 21.90 nm) and interfibrillar spacing (54.28 ± 3.99 nm) of porcine corneal samples. Although GAG depletion did not have any significant effect on the collagen fiber diameter, it significantly increased the interfibrillar spacing in both porcine and human samples. Within the range of linear viscoelastic behavior, the shear stiffness of human and porcine corneal samples did not depend on the shear strain but significantly increased with increasing the applied axial strain. The average complex shear modulus was found to be between 1.0 KPa and 6.5 KPa and between 8.5 KPa and 31 KPa for control porcine and human corneal discs, respectively. The GAG removal caused significant reduction of shear stiffness in both human and porcine corneal samples. Based on these findings, we conclude that sulfated GAGs are important in defining shear properties of porcine and human corneas and significant GAG content variation adversely affects corneal shear modulus.

Corneal cross-linking (CXL) is an effective method to prevent the progression of keratoconus. CXL combined with hypotonic riboflavin solution is a modified treatment for thin corneas, which are deemed to be below the safe thickness threshold. In this study, rabbit corneas were subjected to different hydration levels using different osmolarity of riboflavin dextran solutions before CXL. Inflation testing was performed to evaluate the corneal biomechanical stiffening effect of hypotonic riboflavin solutions crosslinking. One-month post-CXL, the stromal demarcation line depth (DLD) and the biomechanical property parameter - tangent modulus (Et) - were measured. All CXL groups showed higher Et than the corresponding Ctrl groups (all P < 0.001), however, the Et values showed no statistical differences between the CXL-ed groups with different hydration levels (all P > 0.05). The relative depth ratio of DLD to total corneal thickness (TCT) did not show significant differences (P > 0.05), while the DLD was statistically different in three CXL groups (P < 0.001). The research suggested that riboflavin solutions with different osmolarities are suitable for preoperative swelling of corneas with different thickness ranges. Furthermore, crosslinking with hypotonic riboflavin solutions has no significant effect on corneal biomechanical improvement under a certain degree of hydration.

Diabetic retinopathy is a leading cause of vision loss in working adults, with disproportionate impact on women with lowered estrogen. Sex hormones and their receptors are significant to neuroprotection of the inner blood-retinal barrier (iBRB), a tissue that regulates transport across the neuroretina and vasculature. Moreover, high glucose levels in diabetes lead to the formation of advanced glycation end products (AGEs), which promote inflammation and iBRB breakdown to result in vision loss. This study examined the effects of supplemental estradiol on cell reactivity and cell barrier resistance within an in vitro model of hyperglycemia. Changes in morphology and expression of reactive oxygen species were examined when cells were exposed to a hyperglycemic medium containing AGEs, with and without supplemental estradiol. Cell morphology was assessed via changes in cell area and cell shape index, while intracellular ROS levels were measured using a ROS-sensitive dye. In addition, trans endothelial resistance (TEER) assays were used to measure changes in cell barrier function in response to hyperglycemic conditions, with and without supplemental estradiol. Results show that ROS levels in Müller glia in hyperglycemic conditions significantly decreased in response to supplemental estradiol. The estradiol further increased the resistivity of Müller glia and endothelial cell barriers cultured in high glucose and AGEs. This project illustrates the restorative effects of estradiol in collective responses of cell barriers formed by endothelial cells and Müller glia.

Age-related macular degeneration is a retinal disease that severely impacts vision in the older population. Its gene-related heterogeneity has not been fully studied, increasing the burden of precise treatment, prevention and prognosis. Genetic variation and related information were collected, annotated and expanded from multiple related websites, and all the data were integrated into the online platform AMDGKB. Users can visit this database via the following link: http://amdgd.bioinf.org.cn/for their personalized applications knowledge-guided modeling and applications. This study also explored the heterogeneity of ethnicity and AMD subtypes via genetic variation, functional enrichment analysis and protein‒protein interactions. These results suggest that VEGFA, MT2A, CCL2 and SERPINF1 play different roles in the development of AMD in different ethnic groups. The enrichment analysis also revealed differences in the pathogenesis pathways of different ethnic groups and AMD subtypes. This study highlights that genetic heterogeneity needs to be considered in the process of diagnosis and treatment. AMDGKB provides information for investigating the transformation of genetic variation during AMD progression, as well as for future personalized applications in the diagnosis and prognosis of AMD.