中文摘要：

目的探讨激活素A（ActivinA）对巨噬细胞系RAW264.7细胞活性的调节作用及其可能的机制。方法取对数生长期的小鼠巨噬细胞系RAW264.7细胞,加入1μg/ml脂多糖（LPS）,继续培养8h,采用ELISA法检测细胞分泌ActivinA水平;分别加入ActivinA、LPS和ActivinA＋LPS,中性红染料法检测细胞吞饮活性;流式细胞术分析细胞表面分子MHCⅠ、MHCⅡ及Toll样受体4（TLR4）的表达水平。结果LPS呈时间依赖性刺激RAW264.7细胞分泌ActivinA;ActivinA可明显促进静息RAW264.7细胞的吞饮活性,而对MHCⅠ、MHCⅡ及TLR4的表达水平无明显影响;ActivinA和LPS共同作用,ActivinA明显抑制了LPS活化的RAW264.7细胞的吞饮活性,并下调TLR4的表达。结论ActivinA可能以自分泌/旁分泌形式参与巨噬细胞活性调节,其抑制LPS作用与TLR4表达有关。

英文摘要：

Objective To investigate the regulatory effect of activin A on activity of murine macrophage RAW264.7 and its possible mechanism. Methods The RAW264,7 cells at logarithmic growth phase were added with 1 μg/ml LPS and further cultured for 8 h, then determined for activin A level by ELISA. Meanwhile, the RAW264.7 cells at logarithmic growth phase were added with activin A, LPS and activin A ＋ LPS respectively and determined for pinocytic activity by neutral red staining. The expression levels of MHC Ⅰ, MHC Ⅱ and Toll-like receptor 4 （TLR4） on surface of RAW264.7 cells were determined by flow cytometry. Results LP5 showed a time-dependent stimulating effect on the secretion of activin A by RAW264.7 cells. Activin A increased the pinocytic activity of stationary RAW264.7 cells significantly, while showed no significant effect on the expression levels of MHC Ⅰ , MHC Ⅱ and TLR4. When RAW264.7 cells were treated with activin A ＋ LPS, activin A inhibited the pinocytic activity of LPS-activated RAW264.7 cells significantly and down regulated the TLR4 expression. Conclusion Activin A might participate in the regulation of activity of macrophages by autoerine or paracrine, and its inhibitory effect on LPS might be related to TLR4 expression.