橙皮素对血管内皮细胞NO分泌功能的影响

Effect of Hesperetin on Release of Nitric Oxide From Endothelial Cells

考察了橙皮素对人脐静脉内皮细胞（HUVECs）NO分泌功能的影响，探讨其作用机制。为此采用DAN法测定HUVECs分泌NO的水平，用人乳腺癌MCF-7细胞（雌激素受体阳性）促增殖实验和报告基因模型实验评价橙皮素的雌激素样活性。结果显示在内源雌激素水平较低的条件下，橙皮素在12.5-100μmoVL浓度范围内，能够促进HUVECs分泌NO，并呈剂量依赖性。此作用能够被雌激素受体拮抗剂ICI182，780和放线菌素D阻断。橙皮素与E2同时作用时，HUVECs分泌NO水平较两者单独作用时显著下降。而在内源雌激素水平较高的条件下，橙皮素抑制HUVECs分泌NO。橙皮素能够促进MCF-7细胞增殖，并且能够被ICI182，780完全阻断，同时，橙皮素能够部分拮抗E2对MCF-7细胞的促增殖作用。另外，橙皮素能够诱导ERa控制的报告基因表达。从而可认为橙皮素属于雌激素受体部分激动剂，对血管内皮细胞NO分泌功能具有调节作用，其机理涉及雌激素受体信号途径和基因转录调节。

Objective to investigate the effect of hesperetin on release of nitric oxide from cuhured human umbilical vein endothelial cells （HUVECs） and possible mechanism. Methods Fluorometric assay with 2, 3-diaminonaphthalene （DAN） was employed to determinate the concentration of nitrite in medium, indicating NO production from HUVECs. The modified MCF -7 cell proliferation assay and the reporter-gene assay were used to evaluate the estrogenic activity of hesperetin. Results at relative low level of endogenous estrogen, hesperetin （12.5 -100 μmol/L） promoted the release of NO from HUVECs in a dose-dependent manner, which could be inhibited by ICI182,780 and actinomycin D. When HUVECs were treated with combination of hesperetin and E2, the level of NO released from HUVECs was lower than that of single treatment. Under high level of endogenous estrogen, hesperetin inhibited the release of NO from HUVECs. Hesperetin significantly promoted the proliferation of MCF -7 cells, which could be completely blocked by ICI182,780. Meanwhile, hesperetin appeared to compromise efficiency of E2. Also hesperetin activated estrogen receptor and induced the expression of Luciferase （reporter gene）. Conclusion hesperetin can be classified as a partial agonist of estrogen-re- ceptor and possess regulation activity on NO production from HUVECs. The possible mechanism involves in estrogenic activity and regulation of gene expression.