绿茶多酚对高糖作用下内皮细胞内NO的影响

Effect of Green Tea Polyphenols on NO production in endothelial cells induced by high-glucose

目的通过观察绿茶多酚对高浓度葡萄糖培养的血管内皮细胞NO产生的影响,探讨其对心血管系统的保护机制。方法采用0.4μg/ml和4.0μg/ml的绿茶多酚干预高糖(33mmol/L)刺激的血管内皮细胞,荧光探针DAF-2DA测定各组NO释放水平同时采用一氧化氮合成酶(NOS)试剂盒测定各组内皮型一氧化氮合成酶(eNOS),诱导性一氧化氮合成酶(iNOS)活性水平,免疫印记法测定各组eNOS的蛋白表达。结果绿茶多酚预处理24 h组显著降低内皮细胞内由高糖诱导的NO的大量生成及细胞内iNOS的活性水平(P<0.05),免疫印记显示绿茶多酚可以缓解甚至逆转由高糖刺激导致的内皮细胞eNOS的表达减低(P<0.05)。结论绿茶多酚主要是通过降低高糖环境下内皮细胞iNOS的活性与上调eNOS的表达来平衡内皮细胞内的NO水平。

Objective To observe the effect of green tea polyphenols（GTP） on in endothelial cells when culturing in high glucose,and explore its role in vascular system protection.Methods In cultured monolayer bovine aortic endothelial cells（BAECs）,NO released in either group and the activity of NOS were measured by fluorescence probe DAF-2Da and commercial kit,respectively.The expression of protein eNOS was determined by Western-blot after BAECs were pre-incubated with high glucose（33 mmol/L） and GTPs（0.4μg/ml or 4.0μg/ml） for 24 h.Results Pre-treatment with GTPs for 24 h significantly decreased the NO content and the activity of iNOS in high glucose-stimulated BAECs（P0.05,respectively）.GTPs can also inverse the decreased expression of eNOS induced by high glucose（P0.05）.Conclusion GTPs ameliorates high glucose-induced oxidative damage mainly by decreasing NO which produced by iNOS and may be beneficial in protecting endothelial cells from further oxidative damage.