Decellularized squid mantle scaffolds as tissue-engineered corneal stroma for promoting corneal regeneration.

Corneal blindness is a worldwide major cause of vision loss, and corneal transplantation remains to be the most effective way to restore the vision. However, often there is a shortage of the donor corneas for transplantation. Therefore, it is urgent to develop a novel tissue-engineered corneal substitute. The present study envisaged the development of a novel and efficient method to prepare the corneal stromal equivalent from the marine biomaterials-squid. A chemical method was employed to decellularize the squid mantle scaffold to create a cell-free tissue substitute using 0.5% sodium dodecyl sulfate (SDS) solution. Subsequently, a novel clearing method, namely clear, unobstructed brain imaging cocktails (CUBIC) method was used to transparent it. Decellularized squid mantle scaffold (DSMS) has high decellularization efficiency, is rich in essential amino acids, and maintains the regular fiber alignment. In vitro experiments showed that the soaking solution of DSMS was non-toxic to human corneal epithelium cells. DSMS exhibited a good biocompatibility in the rat muscle by undergoing a complete degradation, and promoted the growth of the muscle. In addition, the DSMS showed a good compatibility with the corneal stroma in the rabbit inter-corneal implantation model, and promoted the regeneration of the corneal stroma without any evident rejection. Our results indicate that the squid mantle can be a potential new type of tissue-engineered corneal stroma material with a promising clinical application.

Phenotypic and Transcriptomics Analyses Reveal Underlying Mechanisms in a Mouse Model of Corneal Bee Sting.

Corneal bee sting (CBS) is one of the most common ocular traumas and can lead to blindness. The ophthalmic manifestations are caused by direct mechanical effects of bee stings, toxic effects, and host immune responses to bee venom (BV); however, the underlying pathogenesis remains unclear. Clinically, topical steroids and antibiotics are routinely used to treat CBS patients but the specific drug targets are unknown; therefore, it is imperative to study the pathological characteristics, injury mechanisms, and therapeutic targets involved in CBS. In the present study, a CBS injury model was successfully established by injecting BV into the corneal stroma of healthy C57BL/6 mice. F-actin staining revealed corneal endothelial cell damage, decreased density, skeletal disorder, and thickened corneal stromal. The terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) assay showed apoptosis of both epithelial and endothelial cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that cytokine-cytokine interactions were the most relevant pathway for pathogenesis. Protein-protein interaction (PPI) network analysis showed that IL-1, TNF, and IL-6 were the most relevant nodes. RNA-seq after the application of Tobradex® (0.3% tobramycin and 0.1% dexamethasone) eye ointment showed that Tobradex® not only downregulated relevant inflammatory factors but also reduced corneal pain as well as promoted nerve regeneration by repairing axons. Here, a stable and reliable model of CBS injury was successfully established for the first time, and the pathogenesis of CBS and the therapeutic targets of Tobradex® are discussed. These hub genes are expected to be biomarkers and therapeutic targets for the diagnosis and treatment of CBS.

Phenotypic and transcriptomic changes in the corneal epithelium following exposure to cigarette smoke.

Cigarette smoke extract (CSE), a complex mixture of compounds, contributes to a range of eye diseases; however, the underlying pathophysiological responses to tobacco smoke remain ambiguous. The purpose of the present study was to evaluate the cigarette smoke-induced phenotypic and transcriptomic changes in the corneal epithelium with a view to elucidating the likely underlying mechanism. Accordingly, for the first time, we characterized the genome-wide effects of CSE on the corneal epithelium. The ocular surface of the mice in the experimental groups was exposed to CSE for 1 h per day for a period of one week, while mice in the control group were exposed to preservative-free artificial tears. Corneal fluorescein staining, in vivo confocal microscopy and scanning electron microscopy were performed to examine the corneal ultrastructure. Transcriptome sequencing and bioinformatics analysis were performed followed by RT-qPCR to validate gene expression changes. The results indicate that CSE exposure disrupted the structural integrity of the superficial epithelium, decreased the density of microvilli, and compromised the corneal epithelial barrier intactness. RNA-seq revealed 667 differentially expressed genes, and functional analysis highlighted the enhancement of several biological processes such as antioxidant activity and the response to oxidative stress. Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that glutathione metabolism and drug metabolism cytochrome P450 were the most relevant pathways contributing to the effects of CSE on the corneal epithelium. Protein-protein interaction (PPI) network analysis illustrated that GCLC, NQO1, and HMOX1 were the most relevant nodes. In conclusion, the present study indicates that CSE exposure induces changes in the phenotype and genotype of the corneal epithelium. The antioxidant response element is essential for counteracting the effects of cigarette smoke on this tissue layer. These results shed novel insights into how cigarette smoke damages this ocular surface.

Measuring abnormal intrinsic brain activities in patients with retinal detachment using amplitude of low-frequency fluctuation: a resting-state fMRI study.

OBJECTIVE: The targets of this study were to access the alternations of spontaneous brain activity in RD patients by amplitude of low-frequency fluctuation (ALFF) method and to explore their relationships with clinical behavioral performance. METHODS: A total of 20 patients with RD (6 males and 14 females), and 20 healthy controls (HCs) (6 males and 14 females) were recruited, and were matched in sex and age. All participants finished the functional magnetic resonance imaging (fMRI) scanning. We applied the ALFF method to detect the spontaneous brain activity. Receiver operating characteristic (ROC) curve was applied to distinguish RD Patients from HCs. RESULTS: RD patients showed decreased ALFF values in the right occipital lobe and right medial frontal gyrus and increased ALFF values in the right frontal superior orbital and left inferior temporal gyrus when compared with HCs. In RD patients, we did not find any relationship between the mean ALFF values and the clinical behavioral performances. CONCLUSION: The RD patients exhibited abnormal spontaneous brain activity in vision and vision related brain regions, which might explore potential pathological mechanism of acute vision loss in RD patients.