Inhibitory effects of interleukin-1 receptor antagonist transfection by sonoporation on synovial cell inflammatory reactions

Administration of an exogenous IL-1 receptor antagonist (IL-1ra) is effective for reducing inflammatory reactions mediated by IL-1. In the present study, I transfected a plasmid containing IL-1ra into synovial cells using sonoporation and investigated the anti-inflammatory effects on inflammatory reactions induced by lipopolysaccharide (LPS) in vitro. IL-1ra-transfected synovial cells produced extracellular IL-1ra, with a remarkable increase seen when the cells were cultured with LPS for 48 hr. Interestingly, though treatment with LPS enhanced the release of IL-1β in the culture supernatant of IL-1ra-transfected cells, a significant decrease of PGE2 release was observed when the cells were cultured with LPS for 60 hr. These results indicate that IL-1ra has a valuable role in regulating inflammatory reactions by synovial cells and suggest that administration of IL-1ra by sonoporation is useful for controlling inflammation due to arthritis.