Effect of diacerein on spontaneous polyarthritis in male New Zealand black/KN mice

Diacerein decreases visceral pain through inhibition of glutamatergic neurotransmission and cytokine signaling in mice

The present study evaluated the antinociceptive effect of the pro-inflammatory cytokines inhibitor diacerein in mice and its possible mechanism of action. The antinociception produced by diacerein was tested at different sites of action, moreover selective antagonists or agonists were used to identify the mechanism that may be involved in its antinociceptive action against acetic acid-induced visceral pain. Diacerein administered systemically (intraperitoneal [i.p.] or intra-gastric [i.g.] routes), supra-spinally (i.c.v.), spinally (i.t.) or peripherally (in association with the irritant agent) inhibited the visceral nociception induced by acetic acid in mice. Interestingly, diacerein treatment (25 mg/kg, i.p. or 50 mg/kg, i.g.) produced long-lasting (for up to 4 h) inhibition of acetic acid-induced nociception. Intraperitoneal treatment of mice with diacerein (25.0 mg/kg) inhibited somatic nociception induced by i.t. injection of glutamate, NMDA, kainate, and trans-ACPD but not that caused by AMPA. Diacerein (5.0-25.0 mg/kg) also produced dose related inhibition of interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α) induced nociception. These results indicate that diacerein produces antinociception by inhibiting glutamatergic transmission through both ionotropic and metabotropic receptors as well as activity of pro-inflammatory cytokines.

Chondroprotective drugs in degenerative joint diseases

Catabolic cytokine and anabolic growth factor pathways control destruction and repair in osteoarthritis (OA). A unidirectional TNF-alpha/IL-1-driven cytokine cascade disturbs the homeostasis of the extracellular matrix of articular cartilage in OA. Although chondrocytes in OA cartilage overexpress anabolic insulin-like growth factor (IGF) and its specific receptor (IGFRI) autocrine TNF-alpha released by apoptotic articular cartilage cells sets off an auto/paracrine IL-1-driven cascade that overrules the growth factor activities that sustain repair in degenerative joint disease. Chondroprotection with reappearance of a joint space that had disappeared has been documented unmistakably in peripheral joints of patients suffering from spondyloarthropathy when treated with TNF-alpha-blocking agents that repressed the unidirectional TNF-alpha/IL-1-driven cytokine cascade. A series of connective tissue structure-modifying agents (CTSMAs) that directly affect IL-1 synthesis and release in vitro and down-modulate downstream IL-1 features, e.g. collagenase, proteoglycanase and matrix metalloproteinase activities, the expression of inducible nitric oxide synthase, the increased release of nitric oxide, and the secretion of prostaglandin E(2), IL-6 and IL-8, have been shown to possess disease-modifying OA drug (DMOAD) activities in experimental models of OA and in human subjects with finger joint and knee OA. Examples are corticosteroids, some sulphated polysaccharides, chemically modified tetracyclines, diacetylrhein/rhein, glucosamine and avocado/soybean unsaponifiables.

Attenuation of inflammatory polyarthritis in TNF transgenic mice by diacerein: comparative analysis with dexamethasone, methotrexate and anti-TNF protocols

The impact of diacerein, an effective cartilage targeted therapy that is used in patients with osteoarthritis, on the development and progression of chronic inflammatory arthritis was evaluated in a tumor necrosis factor (TNF) transgenic mouse model (Tg197). The response to diacerein at 2, 20, or 60 mg/kg daily, as well as the comparative effects of other antiarthritis drugs including dexamethasone (0.5 mg/kg daily), methotrexate (1 mg/kg three times weekly) and an anti-TNF agent (5 mg/kg weekly), were assessed in the Tg197 mice. Treatment was initiated before the onset of arthritis and was continued for 5 weeks. A significant improvement in clinical symptoms was found in all three diacerein treated groups in comparison with untreated groups. Confirming these data, semiquantitative histopathologic analysis of the hind paws revealed a significant reduction not only in cartilage destruction but also in the extent of synovitis and bone erosion in diacerein treated groups in comparison with untreated groups. At the most effective dose tested (2 mg/kg daily), diacerein inhibited the onset of arthritis in 28% and attenuated the progression of arthritis in 35% of the Tg197 mice. Comparative analyses showed diacerein to be more potent than methotrexate but not as effective as dexamethasone or anti-TNF agents in suppressing the progression of the TNF mediated arthritis in this model. These results indicate that diacerein has a disease modifying effect on the onset and progression of TNF driven chronic inflammatory arthritis, suggesting that the prophylactic or therapeutic potential of diacerein in patients with RA should be further examined.