【摘要】 目的 探讨熊果酸(UA)调控血管内皮生长因子(VEGF)/环氧化酶-2(COX-2)/金属基质酶-2(MMP-2)通路减轻糖尿病小鼠视网膜病变损伤的作用机制。方法 建立小鼠糖尿病视网膜病变(DR)模型并分组，UA低、中、高剂量组分别予以10、20、40 mg/kg UA灌胃，对照组和DR组予以等量生理盐水灌胃。采用PAS染色测定小鼠视网膜内皮细胞、周细胞计数及其比值，采用免疫沉淀法测定视网膜组织氧化应激指标[超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)],采用Western blotting检测视网膜组织凋亡相关蛋白(Bcl2、Bax、caspase-3)及VEGF、COX-2、MMP-2蛋白表达情况。结果 与对照组相比，DR组小鼠视网膜组织中内皮细胞计数、内皮细胞/周细胞比值、MDA含量及Bax、Cleaved-caspase-3、VEGF、COX-2、MMP-2蛋白表达均显著升高，而周细胞计数、SOD与GSH-Px活性及Bcl-2蛋白表达均显著降低(P<0.05)。与DR组相比，UA各剂量组干预后，内皮细胞计数、内皮细胞/周细胞比值、MDA含量及Bax、Cleaved-caspase-3、VEGF、COX-2、MMP-2蛋白表达均显著降低，且高剂量组效果最优，而周细胞计数、SOD与GSH-Px活性及Bcl-2蛋白表达均显著升高，并呈现剂量依赖性增强(P<0.05)。结论 UA可通过下调DR小鼠视网膜组织VEGF、COX-2、MMP-2表达，呈剂量依赖性保护DR小鼠视网膜组织，为临床治疗DR提供新的科学根据。更多还原

【Abstract】 Aim To investigate the beneficial effects of ursolic acid(UA) to alleviate retinal injury in diabetic mice through the mechanism of regulating vascular endothelial growth factor(VEGF)/cyclooxygenase-2(COX-2)/matrix metalloproteinase-2(MMP-2) pathway. Methods A diabetic retinopathy(DR) mouse model was established and divided into four groups. The UA low-, medium-, and high-dose groups received 10, 20, and 40 mg/kg UA by gavage, respectively, while the control and DR groups received equal volumes of normal saline. Retinal endothelial cells and pericytes were counted and their ratio was calculated using PAS staining. Oxidative stress markers(superoxide dismutase(SOD), malondialdehyde(MDA), glutathione peroxidase(GSH-Px)) were measured by immunoprecipitation. Apoptosis-related proteins(Bcl-2, Bax, caspase-3) and VEGF, COX-2, and MMP-2 protein expression were detected by Western blotting. Results Compared with the control group, the DR group showed significantly increased retinal endothelial cell count, endothelial cell/pericyte ratio, MDA content, and protein expression of Bax, cleaved caspase-3, VEGF, COX-2, and MMP-2, while pericyte count, SOD and GSH-Px activities, and Bcl-2 protein expression were significantly decreased(P<0.05). Compared with the DR group, all groups treated with different doses of UA xhibited reduced endothelial cell count, endothelial cell/pericyte ratio, MDA content, and protein expression of Bax, cleaved caspase-3, VEGF, COX-2, and MMP-2, with the high-dose group showing the most pronounced effects. Meanwhile, pericyte count, SOD and GSH-Px activities, and Bcl-2 protein expression were significantly increased in a dose-dependent manner(P<0.05). Conclusion UA protects retinal tissue in DR mice in a dose-dependent manner by downregulating the expression of VEGF, COX-2, and MMP-2, providing a new scientific basis for clinical treatment of DR.更多还原