Institute of Integrated Traditional Chinese and Western Medicine, Huashan Hospital, Fudan University, Shanghai, China.
Pharm Biol. 2013 Apr;51(4):433-40. doi: 10.3109/13880209.2012.738332. Epub 2013 Jan 22.
Homocysteine-induced endothelial cellular senescence may contribute to some cardiovascular disorders. Icariin (ICA), a flavonoid derived from Epimedium sagittatum Maxim. (Berberidaceae), has been reported to increase production of nitric oxide (NO) and reduce reactive oxygen species (ROS) levels in human umbilical vein endothelial cells (HUVECs).
To observe the effects of ICA on homocysteine-induced senescence and the underlying mechanisms in HUVECs.
ICA at concentrations of 0.1, 1, and 5 μM was added into homocysteine pretreated HUVECs. Cellular senescence was assayed by senescence-associated β-galactosidase (SA-β-gal) staining and cumulative population doublings (CPDs). ICA (5 μM) was given orally to homocysteine-treated rats, luminal surface of aortic artery of rats was subjected to SA-β-gal staining. Protein expression was measured by western blot.
Homocysteine significantly increased cellular senescence both in vitro and in vivo. After treatment by ICA, the percentage of SA-β-gal-positive cells, and the ROS level significantly decreased. The CPDs were partially restored. ICA also significantly reduced the mean density of SA-β-gal staining in vivo. We found that NO production and phosphorylation of AKT, ERK, and endothelial NO synthase (eNOS) were elevated by ICA in HUVECs. Furthermore, the increased level of NO production was fully abolished by the phosphatidylinositol-3-kinase (PI3K) inhibitor wortmannin. The mitogen-activated protein kinase (MEK) inhibitor PD98059, which can inhibit phosphorylation of ERK, did not show this ability.
Our results indicate that ICA delays homocyteine-induced endothelial senescence in vitro and in vivo. Activation of PI3K/Akt-eNOS-dependent signaling pathway may be responsible for this efficacy of ICA.
同型半胱氨酸诱导的内皮细胞衰老可能导致一些心血管疾病。淫羊藿苷（ICA）是从淫羊藿（Berberidaceae）中提取的一种黄酮类化合物，已被报道可增加人脐静脉内皮细胞（HUVEC）中一氧化氮（NO）的产生并降低活性氧（ROS）水平。
观察 ICA 对同型半胱氨酸诱导的 HUVEC 衰老的影响及其潜在机制。
将浓度为 0.1、1 和 5 μM 的 ICA 加入同型半胱氨酸预处理的 HUVEC 中。通过衰老相关β-半乳糖苷酶（SA-β-半乳糖苷）染色和累积倍增数（CPD）测定细胞衰老。将 ICA（5 μM）口服给予同型半胱氨酸处理的大鼠，对大鼠主动脉管腔表面进行 SA-β-半乳糖苷染色。通过 Western blot 测定蛋白质表达。
同型半胱氨酸显著增加了体外和体内的细胞衰老。ICA 处理后，SA-β-半乳糖苷阳性细胞的百分比和 ROS 水平显著降低，CPD 部分恢复。ICA 还显著降低了体内 SA-β-半乳糖苷染色的平均密度。我们发现 ICA 可提高 HUVEC 中 NO 的产生和 AKT、ERK 和内皮型一氧化氮合酶（eNOS）的磷酸化。此外，PI3K 抑制剂wortmannin 完全消除了 NO 产生水平的增加。丝裂原活化蛋白激酶（MEK）抑制剂 PD98059 可抑制 ERK 的磷酸化，但不具有此作用。
我们的结果表明，ICA 可延缓体外和体内同型半胱氨酸诱导的内皮细胞衰老。激活 PI3K/Akt-eNOS 依赖性信号通路可能是 ICA 发挥这种作用的原因。
