Mailuoning and Luteolin Prevents High Glucose-induced Human Retinal Microvascular Endothelial Cell Apoptosis in Diabetic Retinopathy

The present study is aimed to determine the mechanism of the protective effect of mailuoning and its main component luteolin on diabetic retinopathy. Human retinal microvascular endothelial cells were obtained and cultured in high glucose medium. Different concentrations of mailuoning and luteolin were added to the cells. MTT, flow cytometry and TUNEL staining assays were performed to investigate the effects of mailuoning on high glucose-induced proliferation and apoptosis in human retinal microvascular endothelial cells. Enzyme-linked immunosorbent assay was used to detect changes in inflammatory factors, and qPCR was used to detect the expression of apoptosis-related protein Bax and antiapoptotic protein Bcl-2. Western blot was used to detect changes of VEGFR2 and its phosphorylated p-VEGFR2. After adding mailuoning, cell viability of human retinal microvascular endothelial cells was significantly decreased in a concentration-dependent manner while 200 μg/ml mailuoning was the highest concentration without cytotoxic effects. Under high glucose conditions, apoptosis of human retinal microvascular endothelial cells was remarkably increased in a concentration-dependent manner and 100 μg/ml mailuoning was the optimum concentration on human retinal microvascular endothelial cells. Further studies indicated that mailuoning and luteolin inhibited the expression of apoptotic protein Bax and upregulated the expression of antiapoptotic protein Bcl-2. At the same time, inhibited the expression of inflammatory factors IL-6, TNFα and IL-1β. Mechanism studies have shown that mailuoning and luteolin could inhibit p-VEGFR2. Mailuoning and luteolin could prevent high glucose-induced human retinal microvascular endothelial cell apoptosis in diabetic retinopathy, suggesting that mailuoning and luteolin could be useful in the clinical treatment of diabetic retinopathy.