BACKGROUND The deposition of extracellular matrix (ECM) during hepatic fibrosis is an intermediate process in the progression of multiple chronic liver diseases to cirrhosis. Because activated hepatic stellate cells (HSCs) are the main source of ECM, HSCs activation is the central link in the formation of liver fibrosis. It was reported that the analogs of lipoxin A4 (LXA4) had anti-fibrotic effects, but the mechanisms are still not clear. This study was conducted to explore the possible mechanisms involved in the process of LXA4-mediated inhibition of HSCs activation. METHODS Rat HSC-T6 cells were activated by LPS and treated with LXA4 and/or BOC-2. The levels of ECM were assessed by hydroxyproline (Hyp) kit. The protein levels of α-SMA, Collagen I and III, MMP-2, MMP-9, TGF-β1, PDGF A and B, NF-κB P65, phosphorylated NF-κB P65 (P-P65) and NF-κB inhibitor α (I-κBα) were measured via western blot. The mRNA levels of MMP-2 and MMP-9 were observed by real-time PCR. The contents of TGF-β1 and PDGF were assessed by ELISA kits. Nuclear transfer assay kit was used to assess the activation and translation of NF-κB P65. RESULTS (1) LPS activated HSC-T6 cells and up-regulated α-SMA, but LXA4 decreased LPS-induced α-SMA in HSC-T6 cells. (2) LXA4 inhibited LPS-induced Hyp production, meanwhile down-regulated LPS-induced Collagen I, Collagen III, MMP-2, and MMP-9 in HSC-T6 cells. (3) LXA4 decreased LPS-induced TGF-β1 and PDGF in HSC-T6 cells. (4) LXA4 repressed LPS-activated NF-κB signaling pathway, causing a reduction of I-κBα degradation, NF-κB phosphorylation, and NF-κB p65 transposition in HSC-T6 cells. (4) BOC-2, the blocker of LXA4 receptor, inhibited all the effects of LXA4. CONCLUSION LXA4 inhibited HSCs activation through down-regulation TGF-β1/PDGF, and repression NF-κB signal pathway.

中文翻译：

---

Lipoxin A4通过调节纤维化细胞因子和NF-κB信号通路来抑制肝星状细胞-T6细胞的活化。

背景技术在肝纤维化过程中细胞外基质（ECM）的沉积是多种慢性肝病向肝硬化发展的中间过程。由于活化的肝星状细胞（HSC）是ECM的主要来源，因此HSC的活化是肝纤维化形成的关键环节。据报道，脂蛋白A4（LXA4）的类似物具有抗纤维化作用，但机理尚不清楚。进行这项研究以探讨LXA4介导的HSCs激活抑制过程中可能涉及的机制。方法通过LPS激活大鼠HSC-T6细胞，并用LXA4和/或BOC-2处理。通过羟脯氨酸（Hyp）试剂盒评估ECM的水平。α-SMA，I型和III型胶原蛋白，MMP-2，MMP-9，TGF-β1，PDGF A和B，NF-κBP65，通过蛋白质印迹法检测磷酸化的NF-κBP65（P-P65）和NF-κB抑制剂α（I-κBα）。通过实时PCR观察MMP-2和MMP-9的mRNA水平。用ELISA试剂盒评估TGF-β1和PDGF的含量。核转移分析试剂盒用于评估NF-κBP65的激活和翻译。结果（1）LPS激活了HSC-T6细胞并上调了α-SMA，但是LXA4降低了LPS诱导的HSC-T6细胞中的α-SMA。（2）LXA4抑制LPS诱导的HSC-T6细胞中LPS诱导的Hyp产生，同时下调LPS诱导的I型胶原，III型胶原，MMP-2和MMP-9。（3）LXA4降低了LPS诱导的HSC-T6细胞中的TGF-β1和PDGF。（4）LXA4抑制LSC激活的NF-κB信号通路，导致HSC-T6细胞中I-κBα降解，NF-κB磷酸化和NF-κBp65转座减少。（4）BOC-2，LXA4受体的阻滞剂，抑制了LXA4的所有作用。结论LXA4通过下调TGF-β1/ PDGF和抑制NF-κB信号通路抑制HSCs的活化。