ABSTRACT
@#Objective To investigate the role of tumor necrosis factor alpha stimulated gene/inducible protein 6（TSG-6）on free silica（SiO2 ）-induced secretion of pro-inflammatory cytokine interleukin（IL）-1β by bone-marrow-derived macrophages （BMDMs）. Methods i）BMDMs isolated from bone marrow were divided into eight groups：the control group was untreated； lipopolysaccharide （LPS） group was stimulated by LPS with a concentration of 50 µg/L；The TSG-6 control group was stimulated by 100 µg/L of recombinant mouse TSG-6. SiO2 model group was pre-stimulated with LPS for four hours，and then stimulated with SiO2 suspension at a final concentration of 250 mg/L；Different dose of TSG-6 groups were firstly treated with above concentrations of LPS and SiO2 suspension，then 10，20，50 and 100 µg/L of recombinant mouse TSG-6 were added respectively；After 16 hours of culture，the cells were collected and the level of IL-1β in BMDMs supernatant was detected by enzyme-linked immunosorbent assay（ELISA）to screen optimal concentration of TSG-6. ii）The cells of the control group，LPS group，SiO2 model group，TSG-6 optimal concentration group and TSG-6 control group were collected. The expression of IL-1β and components of its related pathways in BMDMs was detected by Western blot，including IL-1β，pro-IL-1β，caspase-1，pro dcaspase-1，asc type amino acid transport and NOD-like receptor protein 3（NLRP3）. Results i）Compared with the control group，the expression of IL-1β in SiO2 model group was increased significantly（P<0.01）. Compared with SiO2 model group，the expression of IL-1β in 20，50，100 µg/L dose of TSG-6 groups were decreased significantly（all P<0.01），and the optimal concentration of TSG-6 was found to be 100 µg/L. ii）Compared with the control group and LPS group，the relative expression levels of IL-1β，caspase-1 and NLRP3 in SiO2 model group were increased significantly （all P<0.05）. Compared with SiO2 model group，the expression levels of IL-1β、caspase-1 and NLRP3 were decreased in 100 µg/L TSG-6 group（all P<0.05）. Conclusion TSG-6 could inhibit BMDMs to secret pro-inflammatory cytokine IL-1β by down-regulating the expression of NLRP3 and caspase-1.