研究证实PD-L1/PD-1信号通路上调抑制NK细胞功能是肝纤维化发展的重要病理机制，丹参有良好的抗纤维化作用及抑制PD-1表达并上调NK细胞数量的前期工作基础。为此提出“增强NK细胞功能是丹参促进活化的HSC凋亡而发挥抗肝纤维化作用的重要药理机制，调节PD-L1/PD-1信号通路尤其是抑制PD-1分子的表达是丹参促进NK细胞功能的分子药理机制”之科学假说，拟开展：①体内实验设NK抑制剂(ASGM-1)、抗-PD-L1抗体对照，观察丹参抑制PD-L1/PD-1信号通路、促进NK细胞功能与抗肝纤维化的作用；②体外实验分离NK细胞，ASGM-1模拟NK细胞“衰竭”，设抗-PD-L1抗体对照；构建人NK细胞株过表达PD-1，予丹参孵育后再与HSC共培养，验证丹参下调PD-L1/PD-1信号通路促进NK细胞功能而诱导HSC凋亡的抗肝纤维化机制。该研究将进一步揭示丹参防治肝纤维化的免疫作用机制。

The functions of natural killer cells are inhibited by the up-regulation of PD-L1/PD-1 singal pathway, which is the key pathomechanism during the development of liver fibrosis. In our previous studies, Salvia miltiorrhiza (SM) was found to reverse liver fibrosis, down-regulate the expression of PD-1 on the surface of NK cells and up-regulate the numbers of NK cells. Hence we put forward the hypothesis that the pharmacological mechanism of SM against liver fibrosis is involved with promoting the functions of NK cells to accelerate the apoptosis of activated HSC and regulating the PD-L1/PD-1 signal pathway, especially inhibiting the expression of PD-1, to strengthen the functions of NK cells. This project will be developed as follows: Firstly, with the positive control of ASGM-1 (NK inhibitor) and anti-PD-L1 antibody (PD-L1/PD-1 blocker) applied, anti-fibrotic effects of SM on inhibiting the PD-L1/PD-1 signal pathway to promote the functions of NK cells are investigated in vivo. Secondly, primary NK cells are isolated and then are exhausted by ASGM-1. With the positive control of anti-PD-L1 antibody and construction of over-expressed PD-1 gene, NK cell lines are pre-incubated with SM before co-culturing with hepatic stellate cell (HSC), which intend to prove the anti-fibrotic mechanism of SM on promoting the functions of NK cells to accelerate the apoptosis of activated HSC by blocking PD-L1/PD-1 signal pathway. This project will reveal the immunologic mechanism of SM against the liver fibrosis.