Fig. 2

TM enhances M2 polarization by activating the STAT6-PPARγ pathway and regulating downstream reactive oxygen species (ROS) levels. a The ROS level was tested by using a ROS kit. Representative confocal images demonstrated that the levels of ROS were high in M1 macrophages. In contrast, TM-treated M1 macrophages showed low levels of ROS, irrespective of the dose of TM administered. Scale bar, 50 μm. n = 3. b Quantification of ROS level. c Western blotting data revealed a marked increase in IL-4R and phosphorylated STAT6 and a concomitant increase in the production of PPARγ. n = 3. d Quantification of Western blotting data. e PPARγ response element (PPRE) activity was measured by using a luciferase reporter assay. Reporter assay data revealed a marked increase in the activity of PPRE in TM-treated M1 cells. However, supplementation with STAT6 inhibitor (AS1517499, AS) caused a lower level of PPRE activity. n = 3. Mean ± SD. *p < 0.05 compared with M1. #p < 0.05 compared with TM-treated M1