Fig. 2

Hyaluronic acid (HA) concentration, relative concentration of HA with a molecular weight of > 6.1 MDa (HMW HA), and viscosity of the synovial fluid of middle carpal joints (MCJ) and tarsocrural joints (TCJ) following IL-1β-induced synovitis or intra-articular lavage. HA decreased from baseline at 6, 24, and 72 h and at 1, 3, 4, and 5 weeks following synovitis induction in both synovitis MCJ and contralateral MCJ (a). HA decreased from baseline from 6 to 12 h, 72 h to 3 weeks, and at 5 weeks post-lavage in both lavage TCJ and contralateral TCJ (b). HMW HA decreased from baseline in synovitis MCJ for 1 week post-synovitis induction and was less than control MCJ from 6 to 48 h. HMW HA increased above baseline at 5 weeks (c). HMW HA increased from baseline at 48 h and from 3 to 5 weeks post-lavage with no statistical differences from contralateral TCJ (d). Viscosity decreased from baseline for the duration of the study period (4 weeks) following synovitis induction and was less than the contralateral MCJ for the same period (except at 1 weeks) (e). Following lavage, viscosity was unchanged from baseline except for a decrease at 168 h and was less than the contralateral TCJ at 72 h (f). Baseline viscosity between the MCJ and TCJ were statistically different. An asterisk indicates a difference from baseline, and a triangle indicates a difference from the contralateral limb at the same time point. Graphed values are marginal means +/− SEM