Joosten L A, Helsen M M, van Den Berg W B
Department of Rheumatology, University Hospital Nijmegen, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
Ann Rheum Dis. 2000 Mar;59(3):196-205. doi: 10.1136/ard.59.3.196.
The goal of this study was to investigate the role of endogenous interleukin 12 (IL12) in acute murine streptococcal cell wall (SCW) arthritis.
C57black/6 mice were injected intraperitoneally with rat anti-murine IL12 (C17.8), shortly before induction of arthritis by intra-articular injection of 25 microg SCW fragments into the right knee joint. Joint swelling and chondrocyte synthetic function was analysed several days after induction of SCW arthritis. Local cytokine profile was determined, protein by using ELISA and mRNA by RT-PCR technology. To confirm the findings at later time points, tissue chamber model of inflammation was used. Histology was performed to examine cell influx and cartilage damage.
Suppression of joint swelling was noted at days 2 and 4, whereas no suppressive effect of anti-IL12 was found at day 1. Severe inhibition of chondrocyte proteoglycan synthesis was seen at day 1 in both arthritic control and anti-IL12 treated mice. However, chondrocyte function was restored at day 4 of arthritis in the anti-IL12 injected animals, but not in the arthritic controls. Moreover, cell influx in synovial tissue and joint cavity was reduced by anti-IL12 treatment. Neutralisation of IL12 reduced the local levels of IL1beta, IL12 and interferon gamma, when examined shortly after induction of SCW arthritis, whereas tumour necrosis factor alpha levels were not affected. In contrast, IL10 and IL1Ra protein and mRNA levels were strongly up regulated in synovial tissues after IL12 blockade. Enhancement of IL10 and IL1Ra by anti-IL12 was confirmed in a tissue chamber model with SCW induced inflammation.
This study indicates that IL12 is a pro-inflammatory cytokine during onset of acute SCW arthritis. Balances of proinflammatory and anti-inflammatory cytokines were strongly improved by anti-IL12 treatment.
本研究旨在探讨内源性白细胞介素12（IL12）在急性小鼠链球菌细胞壁（SCW）关节炎中的作用。
在通过向右侧膝关节内注射25微克SCW片段诱导关节炎之前不久，给C57黑/6小鼠腹腔注射大鼠抗小鼠IL12（C17.8）。在诱导SCW关节炎几天后分析关节肿胀和软骨细胞合成功能。通过酶联免疫吸附测定法（ELISA）测定蛋白质，利用逆转录-聚合酶链反应（RT-PCR）技术测定局部细胞因子谱中的mRNA。为了在后续时间点证实研究结果，采用了炎症组织腔室模型。进行组织学检查以检测细胞浸润和软骨损伤情况。
在第2天和第4天观察到关节肿胀受到抑制，而在第1天未发现抗IL12有抑制作用。在关节炎对照组和抗IL12处理的小鼠中，在第1天均观察到软骨细胞蛋白聚糖合成受到严重抑制。然而，在注射抗IL12的动物中，关节炎第4天时软骨细胞功能得以恢复，而关节炎对照组则未恢复。此外，抗IL12处理减少了滑膜组织和关节腔中的细胞浸润。在诱导SCW关节炎后不久进行检测时，IL12的中和降低了局部IL1β、IL12和干扰素γ的水平，而肿瘤坏死因子α水平未受影响。相反，在阻断IL12后，滑膜组织中IL10和IL1Ra的蛋白质和mRNA水平强烈上调。在SCW诱导炎症的组织腔室模型中证实了抗IL12对IL10和IL1Ra的增强作用。
本研究表明，在急性SCW关节炎发病期间，IL12是一种促炎细胞因子。抗IL12治疗显著改善了促炎和抗炎细胞因子之间的平衡。
