Regulation of hyaluronan production in human synovial cells by Interleukin-1b

Objectives:To investigate the regulatory roles of interleukin 1 (IL-1) b on hyaluronan (HA) synthesis and hyaluronan synthase (HAS) expression by human synovial lining cells. Methods: Concentrations of HA in culture supernatants of synovial cells with or without stimulation by IL-1b (0.1-10ng/ml) were measured by radioimmunochemical assay. HAS2 and HAS3 mRNA Levels of the cells with or without stimulation were detected by semi-quantitative reverse transcribed polymerase chain reaction. Results: HA synthesis was significantly augmented by 1ng/ml IL-1b. Expression of HAS mRNA was assessed in cultured cells treated with IL-1b. The mRNA for HAS2 was enhanced about 2.7 fold, and 3.2 fold for HAS3 with 1ng/ml IL-1b after 24-hour stimulation. Conclusions:These results indicate that IL-1b regulate HAS expression, and consequently promote the secretion of HA, in particular in low molecular-weight HA. This may be the reason why increased HA can be detected in inflamed temporomandibular joint (TMJ) but the symptoms of patients can't be relieved.