| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
We developed rabbit recombinant IL-1beta and IL-1ra, as well as antibodies against these cytokines. Using these materials and anti-rabbit TNFalpha, we investigated the role of IL-1 and TNFalpha in the pathogenesis of LPS-arthritis in rabbits. In the LPS-induced arthritis leukocyte infiltration peaked at 9 hrs while destruction of caltilagepeaked at 24 hrs of the inflammation. When 10mug of IL-1ra was injected simulataneously with LPS,the resulting neutrophil infiltration was inhibited by 70% during a whole observation period until 48 hrs and destruction of caltilage was completely prevented. Anti-TNFalpha(100mug) antibody also inhibited neutrophil infiltration by 70% and completely prevented destruction of caltilage. A combination of these two inhibitory substances produced furher suppression of neutrophil-infiltration by more than 90% and complete abrogation of caltilage-destruction. In the LPS-arthritis, production of IL-1 peaked at 6hr and its amount was 196.7 pg/joint and the most of the produced IL-1 was beta in form. Production of TNFalpha peaked at 2hr and its amount was 12.5 ng/joints.To investigate the role of neutrophils in the destruction of caltilate, we made neutropenic rabbits using i.v. nitrogen mustard. LPS induced no caltilage destruction and no production of IL-1beta in the neutropenic rabbits, while production of TNF-alpha was unchanges incomparison with non-leukopenic rabbits. Injection of IL-1beta (187 pg) into the leukopenic rabbits did not result in destruciton of caltilage. Thus, both TNFalpha and IL-1beta is the key mediators for induction of LPS-stimulated arthritis. But, these cytokines are not directly responsible for tissue damage. Next, we investigated a production which may involved in the destruction of caltilage and we found that neutrophilderived superoxide anion and elastase is responsible for destruction of caltilage in this inflammation.
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