Regulation role of low dose interinkin-18 in murine collagen-induced arthritis / 中华风湿病学杂志

ABSTRACT

Objective To investigate the effect of exogenous murine interlukin-18 (mIL-18) on early and established murine coUagen-induced arthritis (CIA). Methods Mice were injected intraperitoneally with IL-18 (0.2 μg/mouse) daily for 5 days before or after the onset of CIA. The response was monitored visually by macroscopic scoring. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to determine the mRNA expression of cytokines in patella with adjacent synovium in CIA mouse. Histolpgy of knee synovium was used to assess the occurrence of cartilage destruction and bone erosions. Results IL-18 alone had no effect on macroscopic score, occurrence of arthritis, advancement of histology on early stage of CIA. Moreover, expression of Th 1 cytokines and Th2 cytokines in the synovial tissue and" articular cartilage remained unchanged compared with the control group, however, a pronounced progression of histology was found in mice treated with IL-18 in estabhshed CIA. Forty-three days after immunization, the macroscopic score in the treated group (0.33±0.11 ) was significantly improved than in the control group (0.25±0.09) (P<0.05). Moreover, the mRNA levels of IL-10 and IL-18BP both in the synovial tissue and in the articular cartilage in the treated groups decreased significantly than those in the control groups (P<0.05). Conclusion Low dose mIL-18 alone has no effect on early stage CIA. But pronounced exacerbation is found in mice treated with IL-18 on established arthritis, which supports that IL-18 initiates this effect by inhibiting IL-10 and IL-18 BP.