川芎嗪抑制血管紧张素II诱导的平滑肌细胞NF-κB激活和骨形成蛋白-2表达降低(英文)

Tetramethylpyrazine inhibits agiontensin II-induced nuclear factor-κB activation and bone morphogenetic protein-2 downregulation in rat vascular smooth muscle cells

本文旨在观察血管紧张素II (angiotensin II, Ang II)对血管平滑肌细胞核转录因子-κB (nuclear factor-κB, NF-κB)的活性及骨形成蛋白-2 (bone morphogenetic protein-2, BMP-2)表达的影响,以探讨Ang II参与动脉粥样硬化的机制,并探讨川芎嗪是否能抑制Ang II的促动脉粥样硬化作用。采用Western blot、免疫组化和原位杂交等方法分别检测Ang II刺激和川芎嗪干预后NF-κB活性、BMP-2 蛋白和 mRNA 表达的变化。结果显示:(1) Ang II 刺激激活 NF-κB。Ang II 刺激 15 min 即有 NF-κB p65核转移,30 min 达高峰(P<0.01),1 h 后减退。川芎嗪抑制 Ang II诱导的NF-κB激活,与Ang II组比较,川芎嗪 + Ang II组NF-κB活性显著降低 (P<0.01)。 (2) Ang II 刺激 6 h 时 BMP-2 表达增强(P<0.05),12 h 时减弱(P<0.01),24 h 时更弱(P<0.01)。川芎嗪 + Ang II组中,川芎嗪干预6 h 时BMP-2 表达亦增强,12 与24 h 时保持正常水平。 (3) 川芎嗪对正常细胞的NF-κB活性和BMP-2 表达无影响。以上结果表明,Ang II刺激后激活NF-κB并最终使生长抑制因子BMP-2 表达下降,这可能是其参与动脉粥样硬化发生的机制之一。BMP-2 一过性增高可能不依赖NF-κB通路的激活。川芎嗪可抑制Ang II诱导的NF-κB激活与 BMP-2 表达降低,提示它在抗动脉粥样硬化形成中起重要作用。

Tetramethylpyrazine （TMP）, an effective component of traditional Chinese medicine Chuanxiong, is commonly used to resolve embolism. Its possible therapeutic effect against atherosclerosis has received considerable attention recently. Angiotensin Ⅱ （Ang Ⅱ） is highly implicated in the proliferation of vascular smooth muscle cells （VSMCs）, resulting in atherosclerosis. The mecha- nisms of TMP in the proliferation of VSMCs induced by Ang H remain to be defined. The present study was aimed to study the effect of TMP on Ang Ⅱ-induced VSMC proliferation through detection of nuclear factor-κB （NF-κB） activity and bone morphogenetic protein-2 （BMP-2） expression. Primary cultured rat aortic smooth muscle cells were divided into the control group, Ang Ⅱ group, Ang Ⅱ ＋ TMP group and TMP group. Cells in each group were harvested at different time points （15, 30 and 60 min for detection of NF-κB activity; 6, 12 and 24 h for measurement of BMP-2 expression）. NF-κB activation was identified as nuclear staining by irnmtmohistochemistry. BMP-2 expression was observed through Western blot, immunohistochemistry and in situ hybridization. The results showed that： （1） Ang Ⅱ stimulated the activation of NF-κB. Translocation of NF-κB p65 subunit from cytoplasm to nucleus appeared as early as 15 min, peaked at 30 min （P〈0.01） and declined after 1 h. （2） TMP inhibited Ang H-induced NF-κB activation （P〈 0.01）. （3） Ang H increased BMP-2 expression at 6 h but declined it significantly at 12 and 24 h （P〈0.01）. （4） BMP-2 expression was also kept at high level at 6 h in Ang Ⅱ ＋ TMP group but maintained at the normal level at 12 and 24 h. （5） There was no significant difference in NF-κB activation and BMP-2 expression between the control group and TMP group. These results indicate that TMP inhibits Ang Ⅱ-induced VSMC proliferation through repression of NF-κB activation and BMP-2 reduction, and BMP-2 expression is independent of the NF-κB pathway. In conclusion, TMP has therapeutic potential for the treatment of atherosclerosis.