Effects and mechanisms of Cryptotanshinone on rats with adjuvant arthritis.

Background: Cryptotanshinone (CT) is the major active constituent of Salvia miltiorrhiza Bunge. The present study was carried out to investigate the effects of CT on rats with adjuvant arthritis (AA).

Methods: AA was induced by the metatarsal footpad injection with complete Freund's adjuvant in male Sprague-Dawley rats. The secondary inflammatory reaction was evaluated by hind paw swelling and the polyarthritis index. Activity of interleukin-1 (IL-1) was detected by the concanavalin A-induced thymocytes proliferation assay. The lymphocytes proliferation and IL-2 production were assayed by 3-(4,5-2dimethylthiazal-2yl)2,5-diphenyltetrazoliumbromide (MTT) and activated mouse splenocytes proliferation, respectively.

Results: Intragastric administration of CT (50 and 100 mg/kg) significantly decreased secondary inflammatory reactions and increased the spleen and thymus index. There was a marked immunologic and inflammatory response in the AA model, which was accompanied by the decrease of thymocyte proliferation and IL-2 production as well as the increase of IL-1 production. CT apparently enhanced thymocyte proliferation and decreased IL-1 production in AA rats.

Conclusion: These results indicate that CT may exert its anti-inflammatory and immunoregulatory effects through inhibiting lymphocyte proliferation and production of pro-inflammatory mediators.