Inhibition of collagen II arthritis by simultaneous administration of concanavalin A and other substances with antigen emulsion

Suppression of adjuvant arthritis by kappa-opioid receptor agonist: effect of route of administration and strain differences

It is well established that kappa-opioid receptor agonists exert antiinflammatory and antihyperalgesic effects during nonspecific inflammation as well as suppressive effects on the development of humoral and cell-mediated immune responses to foreign antigens. The aim of this study was to investigate the ability of the kappa-opioid receptor agonist MR 2034 to modulate adjuvant arthritis in the rat. In the first series of experiments, treatments of Wistar rats were performed using several routes of drug administration: intraperitoneal (ip), intracaudal (ic), intracerebroventricular (icv) and intraplantar (ipl). MR 2034 significantly suppressed joint swelling after ip and ic treatment, slightly reduced inflammation after ipl treatment, and did not produce any effect after icv treatment. In the second series of experiments, the suppressive effect of ip injected MR 2034 was investigated using Wistar, Dark August (DA) and Lewis rats. In Wistar rats, MR 2034 significantly decreased the incidence of adjuvant arthritis, and suppressed mean joint score and aggregate joint score. Similarly, in DA rats treated with MR 2034, mean arthritic score was significantly suppressed, but other clinical parameters were not affected. In Lewis rats, however, ip treatment with MR 2034 failed to produce any suppressive effect on joint disease and even potentiated the initial development of arthritis. These data suggest that immunosuppressive and antiinflammatory action of MR 2034 markedly depend on the route of drug administration and strain susceptibility to opioids.

Lack of adjuvanticity of human recombinant interleukin-1 beta in collagen induced arthritis in rats

We investigated the influence of human recombinant interleukin-1 beta (hrIL-1 beta) on the time-course of collagen induced arthritis (CIA) when injected concomitantly with the arthritogenic emulsion. Three sensitizing procedures were compared. The control group received type II collagen only. The other groups differed by the adjunction of demonstrated (MDP) or potential (IL-1 beta) adjuvant. No adjuvant effect of IL-1 was observed as judged on clinical or radiological scores. On the contrary, MDP significantly worsened the lesions of the injected right hindpaw, and increased the incidence of CIA. Surprisingly, humoral response to type II collagen was decreased in the group receiving IL-1 beta. This might be explained by a non specific increase of antigen clearance.