Figure 6. Reversal of effect on hyaluronan on opposition to outflow.

A, the joint was first infused with 3.6 g l⁻¹ rooster comb hyaluronan solution (bottom curve), then washed out (5 flexion-extension cycles per wash, 20 washes), and reinfused with Ringer solution (upper curve). Hyaluronan has not irreversibly raised outflow resistance. B, comparison of trans-synovial flows during ascending pressure steps followed by descending pressure steps, in the presence of rooster comb hyaluronan (mean ±s.e.m., 3 joints). Arrows indicate sequence. Flows at a given pressure in the pressure reduction phase are no smaller than in the pressure increment phase (paired t test). The increased opposition to fluid outflow following pressure increments is thus reversed by lowering pressure.