Temporary alleviation of MAPK by arbutin alleviates oxidative damage in the retina and ARPE-19 cells.

Dry age-related macular degeneration (AMD) is one of the main diseases that causes blindness in humans, and the number of cases is increasing yearly. However, effective treatments are unavailable, and arbutin (ARB) has been reported to have antioxidant, anti-inflammatory, and anti-aging effects in other age-related diseases. However, whether ARB can be used to treat dry AMD remains unknown. To explore the therapeutic potential and molecular mechanism of arbutin in the treatment of dry AMD. MTT assays, reactive oxygen species (ROS) production assays, flow cytometry assays, qPCR and western blotting were used to assess the impact of ARB on human RPECs induced by H2O2. A transcriptome sequencing assay was used to further explore how ARB acts on human RPECs treated with H2O2. Hematoxylin and eosin (H&E) staining and total antioxidant capacity (T-AOC) assays were used to observe the impact of ARB on mouse retina induced by sodium iodate. ARB counteracted the H2O2-induced reduction in human RPECs viability, ARB reversed H2O2-induced cellular ROS production by increasing the expression of antioxidant-related genes and proteins, ARB also reversed H2O2-induced cell apoptosis by altering the expression of apoptosis-related genes and proteins. Transcriptome sequencing and western blotting showed that ARB reduced ERK1/2 and P-38 phosphorylation to prevent H2O2-induced oxidation damage. The in vivo experiments demonstrated that ARB protected against retinal morphology injury in mice, increased serum T-AOC levels and increased antioxidant oxidase gene expression levels in the mouse retina induced by sodium iodate. We concluded that ARB reversed the H2O2-induced decrease in human RPECs viability through the inhibition of ROS production and apoptosis. The ERK1/2 and P38 MAPK signaling pathways may mediate this process. ARB maintained retinal morphology, increased serum T-AOC level and improved the expression of antioxidant oxidase genes in mice.

Type I Collagen-Adhesive and ROS-Scavenging Nanoreactors Enhanced Retinal Ganglion Cell Survival in an Experimental Optic Nerve Crush Model.

Traumatic optic neuropathy (TON) is a severe condition characterized by retinal ganglion cell (RGC) death, often leading to irreversible vision loss, and the death of RGCs is closely associated with oxidative stress. Unfortunately, effective treatment options for TON are lacking. To address this, catalase (CAT) is encapsulated in a tannic acid (TA)/poly(ethylenimine)-crosslinked hollow nanoreactor (CAT@PTP), which exhibited enhanced anchoring in the retina due to TA-collagen adhesion. The antioxidative activity of both CAT and TA synergistically eliminated reactive oxygen species (ROS) to save RGCs in the retina, thereby treating TON. In vitro experiments demonstrated that the nanoreactors preserve the enzymatic activity of CAT and exhibit high adhesion to type I collagen. The combination of CAT and TA-based nanoreactors enhanced ROS elimination while maintaining high biocompatibility. In an optic nerve crush rat model, CAT@PTP is effectively anchored to the retina via TA-collagen adhesion after a single vitreous injection, and RGCs are significantly preserved without adverse events. CAT@PTP exhibited a protective effect on retinal function. Given the abundance of collagen that exists in ocular tissues, these findings may contribute to the further application of this multifunctional nanoreactor in ocular diseases to improve therapeutic efficacy and reduce adverse effects.

Long-acting acid-sensitive ketal-linked dexamethasone microcrystals for treating experimental autoimmune uveitis.

Corticosteroids have for some time been used as first-line drugs for the topical treatment of noninfectious uveitis, but poor ocular bioavailability and the rapid clearance of eye drops necessitate frequent dosing, reducing patient compliance. In this study, we used an acid-sensitive stearoxyl-ketal-dexamethasone pro-drug microcrystals (SKD MCs), which is consistently safe and effective in the control of uveitis inflammation in rats. We used a rat model of experimental autoimmune uveitis (EAU) to evaluate the effects of SKD MCs in terms of clinical manifestations, molecular biology, pathological histology, and visual electrophysiology compared to dexamethasone sodium phosphate injection or phosphate-buffered saline. SKD MCs significantly reduced inflammation in EAU, improved the ability to suppress inflammatory cytokines and to protect retinal function, and significantly reduced retinal microglia activation, with no increase in intraocular pressure throughout the treatment. Our results indicate that the SKD MCs formulation holds promise as a new strategy for the treatment of noninfectious uveitis and potentially other ocular inflammatory diseases.

O3 oxidation combined with semi-dry method for simultaneous desulfurization and denitrification of sintering/pelletizing flue gas.

With the vigorous development of China's iron and steel industry and the introduction of ultra-low emission policies, the emission of pollutants such as SO2 and NOx has received unprecedented attention. Considering the increase of the proportion of semi-dry desulfurization technology in the desulfurization process, several semi-dry desulphurization technologies such as flue gas circulating fluidized bed (CFB), dense flow absorber (DFA) and spray drying absorption (SDA) are briefly summarized. Moreover, a method for simultaneous treatment of SO2 and NOx in sintering/pelletizing flue gas by O3 oxidation combined with semi-dry method is introduced. Meantime, the effects of key parameters such as O3/NO molar ratio, CaSO3, SO2, reaction temperature, Ca/(S+2N) molar ratio, droplet size and approach to adiabatic saturation temperature (AAST) on denitrification and desulfurization are analyzed. Furthermore, the reaction mechanism of denitrification and desulfurization is further elucidated. Finally, the advantages and development prospects of the new technology are proposed.

Simultaneous removal of SO2 and NO using a spray dryer absorption (SDA) method combined with O3 oxidation for sintering/pelleting flue gas.

Based on the demand of sintering/pelleting flue gas ultra-low emission, a semi-dry method using a spray dryer absorber (SDA) combined with O3 oxidation was proposed for simultaneous removal of SO2 and NO. Effects of O3 injection site, O3/NO molar ratio, and spray tower temperature on the removal efficiencies were investigated. It was revealed that both desulfurization and denitrification efficiencies could reach to 85% under the conditions of setting O3 injection site inside of tower, O3/NO molar ratio 1.8, spray tower temperature 85°C, Ca/(S + 2 N) molar ratio 2.5 and slurry flow rate 300 mL/hr. CaSO3/Ca(OH)2 mixture slurry was used as absorbent to simulate operating conditions in iron and steel industry. The result shows that the addition of CaSO3 weakens both removal efficiencies. In addition, the reaction mechanism of simultaneous removal of SO2 and NO using SDA combined with O3 oxidation was proposed.

Simultaneous Removal of NO x and SO2 by MgO Combined with O3 Oxidation: The Influencing Factors and O3 Consumption Distributions.

Simultaneous removal of NO x and SO2 by MgO combined with O3 oxidation was studied. The effects of the O3/NO molar ratio, oxidation temperature, and oxidation residence time on N2O5 decomposition and O3 consumption distributions were systematically illustrated, which is of great significance for improving NO x removal efficiency and reducing O3 consumption in practical application. When the O3/NO molar ratio was greater than 1.0, the highest N2O5 yield was achieved at 90 °C. The NO x removal efficiency reached 96.5% at an O3/NO molar ratio of 1.8. The oxidation temperature increased from 90 to 130 °C, resulting in the decrease of N2O5 yield, the improvement of O3-ICC (O3 invalid cycle consumption) caused by N2O5 decomposition, and the decrease of NO x removal efficiency from 96.5 to 76%. Besides, the effects of pH, SO2 concentration, and MgSO3 addition on NO x removal efficiency were also investigated. The results showed that the removal efficiency of NO x decreased with the increase of SO2 concentration, while MgSO3 addition into MgO slurry could promote the absorption of NO2 due to the reaction between NO2 and SO3 2-.