Fig. 4: Photomicrograph from 5 μm sections of synovial membrane (lateral, medial, central) stained with H&E from horses treated with different doses of viral vectors with the corresponding sham control joints (bottom panel).

The synovial membrane from the horse administered the highest viral dose (5 x 1012vp scAAVIL-1ra) showed perivascular lymphocytic infiltration (black arrows; inset) and subintimal fibrosis (black arrowheads). Sections of synovial membrane from lower dosed joints lack any adverse tissue reactions. Plates are at 10X and insets are at 40X magnification.