Inhibition of IL-1 release from human monocytes and suppression of streptococcal cell wall and adjuvant-induced arthritis in rats by an extract of Tripterygium wilfordii Hook

Protective effect of Asarum extract in rats with adjuvant arthritis

The aim of the present study was to investigate the protective effect of Asarum extract on rats with adjuvant arthritis (AA) and to determine the underlying mechanism. An AA model was established by injecting Freund’s complete adjuvant into the rats. The degree of toe swelling, arthritis index, spleen index, and the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 were measured. In addition, the underlying molecular mechanism was investigated using murine macrophage-derived RAW 264.7 cells. Asarum extract was found to significantly reduce the severity of arthritis by decreasing hind paw swelling, the arthritis index, the spleen index, and TNF-α, IL-1β and IL-6 expression levels in plasma. In vitro, Asarum extract inhibited the nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling pathways. These results indicate that Asarum extract may be a therapeutic agent for AA and may exert an anti-inflammatory effect by mediating the NF-κB and MAPK signaling pathways.

A Chinese herb Tripterygium wilfordii Hook F in the treatment of rheumatoid arthritis: mechanism, efficacy, and safety

Tripterygium wilfordii Hook F (TwHF) is a Chinese herb with immunosuppressive effects and an established history of use in the treatment of rheumatoid arthritis (RA). Numerous preclinical studies have demonstrated that the extracts from the root of TwHF inhibit the expression of proinflammatory cytokines, proinflammatory mediators, adhesion molecules, and matrix metalloproteinases by macrophages, lymphocytes, synovial fibroblasts, and chondrocytes. TwHF also induces apoptosis in lymphocytes and synovial fibroblasts and inhibits their proliferation. Except numerous uncontrolled clinical trials, there are some prospective, double-blind, randomized, and placebo/sulfasalazine-controlled trials, also demonstrating greater improvement in RA disease activity by TwHF extract than placebo/sulfasalazine. Radiographic progression in RA may also be retarded by TwHF. Therefore, the immunosuppressive, cartilage protective, and anti-inflammatory effects of TwHF extracts are well demonstrated, and TwHF extract is an alternative disease modifying anti-rheumatic drug (DMARD) for the patients with RA refractory to conventional therapy.

Triptolide, a novel immunosuppressive and anti-inflammatory agent purified from a Chinese herb Tripterygium wilfordii Hook F

Triptolide is a diterpenoid triepoxide purified from a Chinese herb Tripterygium Wilfordii Hook F (TWHF). TWHF has been used in traditional Chinese medicine for more than two thousand years. However, its potential value was recognized by the western medicine only after investigators observed the effectiveness of TWHF in the treatment of leprosy and rheumatoid arthritis. Triptolide has been identified as the major component responsible for the immunosuppressive and anti-inflammatory effects of TWHF. Triptolide inhibits both Ca(2+)-dependent and Ca(2+)-independent pathways and affects T cell activation through inhibition of interleukin-2 transcription at a site different from the target of cyclosporin A. Triptolide also has inhibitory effects on a variety of proinflammatory cytokines and mediators and on the expression of adhesion molecules by endothelial cells. Triptolide is effective for the treatment of a variety of autoimmune diseases and in prevention of allograft rejection and graft-versus-host disease in both animals and humans. Moreover, triptolide possesses antitumor and male anti-fertility effect. However, the toxicities of triptolide may be associated with renal, cardiac, hematopoietic and reproductive systems. Currently available data suggest that triptolide is a promising immunosuppressive and anti-inflammatory agent and should be explored further in autoimmune diseases and transplantation.

Prevention of graft-versus-host disease by a novel immunosuppressant, PG490-88, through inhibition of alloreactive T cell expansion

BACKGROUND

PG490-88 is a water soluble, semisynthetic derivative of a novel compound PG490 (triptolide) purified from the Chinese herb Tripterygium Wilfordii Hook F.

METHODS

PG490-88 was administrated into recipient mice in a model (B10.D2-->BALB/c) of lethal graft-versus-host disease (GVHD) to study the effects of PG490-88 on GVHD and on the various steps involved in the pathological course of GVHD.

RESULTS

Injection of PG490-88 i.p. at a dose of 0.535 mg/kg/day for the first 3 weeks after transplantation protected all the recipients from developing GVHD up to 100 days after transplantation. PG490-88 inhibited in vivo both CD4+Vbeta3+ and CD8+Vbeta3+ T cell (alloreactive T cells in this model) expansion in the spleen by 64.09 and 34.02%, respectively, at the time when Vbeta3+ cell expansion was in the logarithmic phase (day 3 after transplantation). Intracellular cytokine staining without further in vitro activation demonstrated 47.42% inhibition of IL-2 production among CD4+ spleen cells in PG490-88-treated mice as compared to GVHD control on day 3 after transplantation. In contrast, CD25 (alpha chain of interleukin-2 receptor) expression did not differ.

CONCLUSIONS

PG490-88 is highly effective in prevention of murine GVHD. The immunosuppressive effect of PG490-88 is mediated by inhibition of alloreactive T cell expansion through interleukin-2 production.