Time course of IT gene expression. (A.) Gene expression was detectable in the CE one week after IT delivery of sc-rAAV2/l (3 × l09 particles/animal). Expression levels increased further after one week and reached a plateau with stable expression at four and twelve weeks, the longest time point tested. Shown is the mean and SEM of expression levels determined by quantitative Western blotting with group sizes of seven to nine animals as indicated (□). No expression was seen in PBS injected control rats (▽). (B.) The one- and four-week time points were repeated in a second group of animals to confirm the rise in EGFP levels during this time frame (○). PBS controls showed again no detectable expression (△).