Luteolin ameliorates cornea stromal collagen degradation and inflammatory damage in rats with corneal alkali burn

Nano-alkaline ion-excited NETs ablative eye drops promote ocular surface recovery

Neutrophil extracellular traps (NETs) promote neovascularization during the acute phase after ocular chemical injury, while the local inflammatory acidic environment delays post-injury repair. Currently, the mechanism of NETs promoting neovascularization has not been fully elucidated, and there is a lack of therapeutic strategies to effectively improve the local microenvironment for corneal repair. In this study, we validated the NETs-M2-angiogenic pathway after injury. Using transcriptomics sequencing and liquid-phase microarray assays, the intrinsic immune cascade mechanism of NETs inducing macrophage M2 polarization and releasing VEGF via PI3K/AKT was identified. Based on this pathology and the physiological need to improve the local inflammatory acidic environment and promote corneal repair, we organically integrated the alkaline ion-rich bioglass with the highly transmissive and highly adhesive filipin protein, and constructed NETs ablative gel eye drops (DMS) that can release DNase I and alkaline ions in a sustained manner. The eye drops restricted the inflammatory interaction of NETs with macrophages from the source, adhered to the corneal surface and continuously released alkaline ions to improve the local acidic inflammatory environment, providing a favorable immune microenvironment for corneal recovery. We established a cell co-culture system and a corneal alkali burn model to further validate the role of DMS in modulating the intrinsic immune cascade of neovascularization for corneal repair and the related mechanisms. In conclusion, based on the biological mechanism of NETs-M2-VEGF after corneal chemical injury, the present study designed eye drops for dual regulation of intrinsic immunity and the inflammatory acid environment, which not only further supplemented and improved the pathophysiological mechanism of corneal neovascularization after chemical injury, but also provided a new way of thinking about corneal regeneration after injury.

Development of an injectable oxidized dextran/gelatin hydrogel capable of promoting the healing of alkali burn-associated corneal wounds

The cornea serves as an essential shield that protects the underlying eye from external conditions, yet it remains highly vulnerable to injuries that could lead to blindness and scarring if not promptly and effectively treated. Excessive inflammatory response constitute the primary cause of pathological corneal injury. This study aimed to develop effective approaches for enabling the functional repair of corneal injuries by combining nanoparticles loaded with anti-inflammatory agents and an injectable oxidized dextran/gelatin/borax hydrogel. The injectability and self-healing properties of developed hydrogels based on borate ester bonds and dynamic Schiff base bonds were excellent, improving the retention of administered drugs on the ocular surface. In vitro cellular assays and in vivo animal studies collectively substantiated the proficiency of probucol nanoparticle-loaded hydrogels to readily suppress proinflammatory marker expression and to induce the upregulation of anti-inflammatory mediators, thereby supporting rapid repair of rat corneal tissue following alkali burn-induced injury. As such, probucol nanoparticle-loaded hydrogels represent a prospective avenue to developing long-acting and efficacious therapies for ophthalmic diseases.

Luteolin: A promising multifunctional natural flavonoid for human diseases

Natural products are closely associated with human health. Luteolin (LUT), a flavonoid polyphenolic compound, is widely found in fruits, vegetables, flowers, and herbs. It is noteworthy that LUT exhibits a variety of beneficial pharmacological properties and holds significant potential for clinical applications, particularly in antitumor, anti-convulsion, diabetes control, anti-inflammatory, neuroprotection, anti-oxidation, anti-cardiovascular, and other aspects. The potential mechanism of action has been partially elucidated, including the mediation of NF-κB, toll-like receptor, MAPK, Wnt/β-catenin, PI3K/Akt, AMPK/mTOR, and Nrf-2, among others. The review that aimed to comprehensively consolidate essential information on natural sources, pharmacological effects, therapeutic and preventive potential, as well as potential mechanisms of LUT. The objective is to establish a theoretical basis for the continued development and application of LUT.

SIRT1/P53 in retinal pigment epithelial cells in diabetic retinopathy: a gene co-expression analysis and He-Ying-Qing-Re formula treatment

Objective

Diabetic retinopathy (DR) is a severe diabetic complication that leads to severe visual impairment or blindness. He-Ying-Qing-Re formula (HF), a traditional Chinese medicinal concoction, has been identified as an efficient therapy for DR with retinal vascular dysfunction for decades and has been experimentally reported to ameliorate retinal conditions in diabetic mice. This study endeavors to explore the therapeutic potential of HF with key ingredients in DR and its underlying novel mechanisms.

Methods

Co-expression gene modules and hub genes were calculated by weighted gene co-expression network analysis (WGCNA) based on transcriptome sequencing data from high-glucose-treated adult retinal pigment epithelial cell line-19 (ARPE-19). The chromatographic fingerprint of HF was established by ultra-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC-Q-TOF-MS). The molecular affinity of the herbal compound was measured by molecular docking. Reactive oxygen species (ROS) was measured by a DCFDA/H2DCFDA assay. Apoptosis was detected using the TUNEL Assay Kit, while ELISA, Western blot, and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used for detecting the cytokine, protein, and mRNA expressions, respectively.

Results

Key compounds in HF were identified as luteolin, paeoniflorin, and nobiletin. For WGCNA, ME-salmon ("protein deacetylation") was negatively correlated with ME-purple ("oxidative impairment") in high-glucose-treated ARPE-19. Luteolin has a high affinity for SIRT1 and P53, as indicated by molecular docking. Luteolin has a hypoglycemic effect on type I diabetic mice. Moreover, HF and luteolin suppress oxidative stress production (ROS and MDA), inflammatory factor expression (IL-6, TNF-α, IL1-β, and MCP-1), and apoptosis, as shown in the in vivo and in vitro experiments. Concurrently, treatment with HF and luteolin led to an upregulation of SIRT1 and a corresponding downregulation of P53.

Conclusion

Using HF and its active compound luteolin as therapeutic agents offers a promising approach to diabetic retinopathy treatment. It primarily suppressed protein acetylation and oxidative stress via the SIRT1/P53 pathway in retinal pigment epithelial cells.