Figure 4.
Repeat injection of scAAV.IL-1Ra does not result in rescue of transgene expression. Similar to the procedure described in Figure 3, five rabbits were injected in both knees with HIG-82-IL-1β-neo cells to establish an inflammatory state. Three days later, the inflamed rabbits and five normal rabbits were then injected with scAAV.IL-1Ra in both knees. At weekly intervals, the knees of the rabbits were lavaged with saline, and IL-1Ra levels measured using ELISA. At 49 days after the initial scAAV.IL-1Ra injection and 14 days after IL-1Ra expression had diminished in all joints, a second intra-articular injection of scAAV.IL-1Ra was administered to all rabbit knees (indicated by an arrow). The knees of all rabbits were lavaged at 3 and 7 days after the second vector injection. Values shown are the mean ± SD IL-1Ra levels at specific time points. A two-sample t-test was conducted for IL-1Ra levels between groups for each day post-injection; using p < 0.05, the only significant difference detected was at day 14 post-injection.