Figure 6.

Potential role of IL-1β in mediating contractile dysfunction. Graphs showing plasma levels of IL-1β from control and arthritic animals (A) and vasoconstriction concentration–response curves to 5-HT in aortic tissues taken from naïve non-immunized animals and incubated for 24 h in the absence (Control) and presence of either 70 or 700 pg·mL⁻¹ IL-1β alone (B) or IL-1β (700 pg·mL⁻¹) in the presence of L-NAME (C), 1400W (D) or indomethacin (Indo) (E). Also shown are elisa-derived levels of MMP-9 in aortic tissues taken from naïve non-immunized animals and incubated for 24 h in the absence (control) and presence of 700 pg·mL⁻¹ IL-1β (F). Plasma levels of IL-1β were elevated in mCIA animals and ex vivo incubation with IL-1β impaired contractile responses to 5-HT. However, the latter was prevented by inhibitors of NO/H₂O₂ and (to a lesser extent) vasodilatory prostanoids. Moreover, the observed ex vivo contractile dysfunction was not associated with a change in MMP-9 protein. *P < 0.05, **P < 0.01 significantly different from the appropriate control, n≥ 4 for all groups.