Bee venom (BV) has been used to relieve pain and reduce inflammation in traditional Oriental medicine, especially in chronic inflammatory diseases such as rheumatoid arthritis (RA). We previously reported that the BV injection into a traditional acupuncture point (Zusanli) reduced arthritis-associated edema and nociceptive responses in Freund's adjuvant-induced arthritis in rats (Kwon et al., 2001). This study was designed to evaluate the anti-inflammatory and anti-cytokine effect of BV on a murine type-II collagen-induced arthritis (CIA) model. Male mice were immunized by spontaneous injection of 100 μg of an emulsion of bovine type-II collagen and complete Freund's adjuvant (CFA), with a booster injection after 2 weeks. In the experimental group, 0.1 ml BV was injected at acupuncture point (Zusanli) near both knees twice a week for a total of 5 times. In the control group, normal saline was injected at the same frequencies. These injections began 5 weeks after the first collagen injection. Starting the 3rd week after the first collagen injection, we examined limb swelling and severity of arthritis twice a week. At 8 weeks, mice were sacrificed and synovial tissue was examined with the light microscope and serum cytokines (IL-1β and TNF-α) were measured by ELISA. The incidence of arthritis, the mean arthritis index and the number of arthritic limbs were significantly lower in the treatment compared to the control group (63% versus 75%, 3.4% versus 8.5%, 23% versus 75%, respectively). Among the serum proinflammatory cytokines, the production of TNF-α in the BV group was suppressed compared to the control group (59+/-4.5 versus 99.5+/-6.5, p <0.05), but IL-1β was not suppressed. The examination of the histopathology of the joints of murine CIA showed decreased inflammation signs and less lymphocyte infiltration after BV acupuncture therapy. Acupuncture therapy with BV suppressed the development of arthritis and caused inhibition of the immune responses in type-II collagen-induced arthritis.
Crocin exerts anti-inflammatory and anti-arthritic effects on type II collagen-induced arthritis in rats
