Faculty of Pharmacy, University of Manitoba, Winnipeg, Manitoba, Canada R3E 0T5; Department of TCM Basic Clinical Research, Beijing University of Chinese Medicine, 11 North No. 3 Road East, Chaoyang District, Beijing 100029, China.
Phytomedicine. 2013 Nov 15;20(14):1330-5. doi: 10.1016/j.phymed.2013.07.010. Epub 2013 Aug 19.
Saikosaponin a (SSa) is a compound extracted from a Chinese herb which has been widely used in treating liver diseases such as liver fibrosis. However, the mechanism of SSa in treatment of liver fibrosis still remain unclear. Our previous study demonstrated that BMP4 stimulated the expression of smooth muscle alpha actin (α-SMA) in the liver. Therefore, the current study investigates the effect of SSa on BMP4 expression during hepatic stellate cell activation in a human hepatic stellate cell line.
LX-2 cells were cultured in DMEM/F12 with fetal bovine serum and treated with SSa in different times and concentrations. The expression of BMP4 was examined by both RT-PCR and western blot analysis. WST-1 proliferation reagent was used to evaluate cell proliferation. α-SMA and Bax protein expression was determined by western blot analysis.
Both mRNA and protein levels of BMP-4 were significantly inhibited in LX-2 cells after 5 μM SSa treatment. SSa significantly inhibited LX-2 proliferation at the concentration of 5μM while BMP-4 had no effect on LX-2 proliferation. BMP-4 increased α-SMA expression in LX-2 while SSa reduced α-SMA expression. In addition SSa could neutralize the effect of BMP-4 on α-SMA expression. SSd also inhibited BMP4 expression but not NG. Bax protein expression was induced in these cells by 5 μM SSa.
SSa could down-regulate BMP-4 expression and inhibit hepatic stellate cell activation. Therefore, SSa could be used for treatment of liver disease with elevated BMP-4 expression.
柴胡皂苷 a（SSa）是一种从中国草药中提取的化合物，已广泛用于治疗肝纤维化等肝脏疾病。然而，SSa 治疗肝纤维化的机制仍不清楚。我们之前的研究表明，BMP4 刺激肝脏中平滑肌α肌动蛋白（α-SMA）的表达。因此，本研究在人肝星状细胞系中研究了 SSa 在肝星状细胞活化过程中对 BMP4 表达的影响。
在含有胎牛血清的 DMEM/F12 中培养 LX-2 细胞，并以不同时间和浓度用 SSa 处理。通过 RT-PCR 和 Western blot 分析检测 BMP4 的表达。使用 WST-1 增殖试剂评估细胞增殖。通过 Western blot 分析测定α-SMA 和 Bax 蛋白表达。
5μM SSa 处理后，LX-2 细胞中 BMP-4 的 mRNA 和蛋白水平均显著抑制。SSa 在 5μM 浓度下显著抑制 LX-2 增殖，而 BMP-4 对 LX-2 增殖没有影响。BMP-4 增加了 LX-2 中的α-SMA 表达，而 SSa 降低了α-SMA 表达。此外，SSa 可以中和 BMP-4 对α-SMA 表达的作用。SSd 也抑制 BMP4 表达，但不抑制 NG。5μM SSa 诱导这些细胞中 Bax 蛋白表达。
SSa 可下调 BMP-4 表达并抑制肝星状细胞活化。因此，SSa 可用于治疗 BMP-4 表达升高的肝脏疾病。
