Abstract: OBJECTIVE: To investigate whether butein protects against LPS-induced inflammation in primary bone marrow macrophages,and to analyze the role of JAK2-STAT3 in this process. METHODS: In order to obtain bone marrow-derived macrophages (BMDM),bone marrows samples from C57BL/6 mice were treated with 40 ng/mL GM-CSF for 7 d. BMDM cells were stimulated with 500 ng/mL LPS for 12 h in the presence or absence of 5,10,20 μmol/L butein. Levels of TNF-α,IL-6 and NO in the culture medium were assessed by ELISA specific kits. To detect intracellular levels of reactive oxygen species (ROS),BMDM were stained with DCFH-DA and analyzed by flow-cytometry. Moreover,Western blot assay was used to detect protein expression of iNOS,p-JAK2,JAK2,p-STAT3 and STAT3. Ratios of p-JAK2/JAK2 and p-STAT3/STAT3 were determined. RESULTS: Exposure to LPS significantly increased the levels of TNF-α,IL-6 and NO in the culture medium of BMDM cells. However,administration of 5,10 and 20 μmol/L butein inhibited the production of these proinflammatory factors in a dose-dependent manner. Flow cytometry assays indicate that butein attenuated ROS generation in LPS-activated BMDM macrophages. In addition,Western blot results suggest that LPS promoted iNOS,p-JAK2 and p-STAT3 protein expression,and butein blunted this process. CONCLUSION: Butein inhibited LPS-induced inflammation in BMDM cells by regulating expressions in the JAK2-STAT3 pathway. Therefore,butein may be useful as a drug for control of inflammatory diseases.

Key words: butein, JAK2, STAT3, macrophages, inflammatory response