acteoside and Diabetic-Retinopathy

Diabetes retinopathy (DR) is one of the most common microvascular complications of diabetes. Retinal pigment epithelial (RPE) cells exposed to a high glucose environment experience a series of functional damages, which is an important factor in promoting the progression of DR. Acteoside (ACT) has strong antioxidant and anti-apoptotic properties, but the mechanism of ACT in DR is not completely clear. Therefore, the purpose of the present study was to explore whether ACT inhibits the damage to RPE cells in a high glucose environment through antioxidative effects to alleviate the DR process. The DR in vitro cell model was constructed by treating RPE cells with high glucose, and the DR in vivo animal model was constructed by injecting streptozotocin (STZ) into the peritoneal cavity of mice to induce diabetes. The proliferation and apoptosis of RPE cells were detected by CCK-8 and flow cytometry assays, respectively. The expression changes in Nrf2, Keap1, NQO1 and HO-1 were evaluated by qRT‒PCR, Western blot and immunohistochemistry analyses. The MDA, SOD, GSH-Px and T-AOC contents were detected by kits. The changes in ROS and nuclear translocation of Nrf2 were observed by immunofluorescence assays. HE staining was used to measure the thickness of the outer nuclear layer (ONL) of the retina, and TUNEL staining was used to detect the number of apoptotic cells in the retinas of mice. In the present study, ACT effectively ameliorated outer retina damage in diabetic mice. In high glucose (HG)-induced RPE cells, ACT treatment had the following effects: improved proliferation, decreased apoptosis, inhibited Keap1 expression, promoted the nuclear translocation and expression of Nrf2, upregulated NQO1 and HO-1 (the target genes of Nrf2) expression, decreased ROS concentration, and increased the levels of the SOD, GSH-Px and T-AOC antioxidant indicators. However, knockdown of Nrf2 reversed the above phenomena, which indicated that the protective function of ACT in HG-induced RPE cells are closely related to Nrf2. In summary, the present study demonstrated that HG-induced oxidative stress injury is inhibited by ACT in RPE cells and the outer retina through the Keap1/Nrf2/ARE pathway.

Topics: Animals; Antioxidants; Diabetes Mellitus, Experimental; Diabetic Retinopathy; Glucose; Glucosides; Kelch-Like ECH-Associated Protein 1; Mice; NF-E2-Related Factor 2; Oxidative Stress; Polyphenols; Reactive Oxygen Species; Retina; Superoxide Dismutase

Reactive oxygen species (ROS) accumulation plays a pivotal role in the onset of cell damage induced by hyperglycemia and represents one of the major factors in the pathogenesis of diabetic retinopathy. In this study, we tested the antioxidants cyanidin-3-O-glucoside (C3G) and verbascoside (Verb) in the protection of retinal endothelium against glucose toxicity ". Increasing amounts (5-50 μM) of C3G, Verb or the combination of both compounds were tested in Human Retinal Endothelial Cells (HREC) grown with normal glucose (5 mM, NG) or high glucose (25 mM, HG).. Reduced cell viability and enhanced ROS levels (evaluated by MTT and H2DCFDA assays, respectively) in HG-stimulated HREC were restored by C3G and Verb in a dose-dependent manner, achieving the maximum protection in the presence of both compounds. Moreover, co-treatment with C3G and Verb worked better than each single molecule alone in the prevention of the disruption of blood-retinal-barrier-like properties by HG in a confluent HREC monolayer, as assessed by trans endothelial electrical resistance (TEER) and Na-Fluorescein permeability assays. Accordingly, C3G and Verb together also better counteracted the HG-induced down-regulation of the tight junction membrane proteins Zonula Occludens-1 and VE-Cadherin evaluated by immunocytochemical and Western blot analyses.. In conclusion, our data indicate that C3G and Verb could efficiently protect the retinal endothelium against high glucose damage.

Topics: Antioxidants; Diabetes Mellitus; Diabetic Retinopathy; Endothelial Cells; Glucose; Glucosides; Humans; Reactive Oxygen Species