FIGURE 1

Transduction efficacy of freeze-dried tendon grafts in vitro and in vivo. (a) 3-mm Freeze-dried mouse flexor digitorum longus (FDL) tendon allografts were loaded with 5 10⁹ transducing units of rAAV-lacZ, and incubated on a confluent monolayer of human embryonic kidney 293 cells for 48 hours (arrow). Representative micrographs of X-gal stained cultures show (b) large numbers of LacZ+ cells proximal to the graft, and (c) sparse staining in peripheral fields away from the graft. rAAV-lacZ loaded FDL allografts were also transplanted into FDL tendon defects of mice (n = 4). Representative micrographs of one end of the rAAV-lacZ loaded FDL allografts stained with antibodies against -galactosidase at (d) 7 days after transplantation and (e) 14 days after transplantation. It is important to note the lack of viable cells and absence of any staining in the freeze-dried allografts (asterisks) that are surrounded by hypercellular and intensely stained fibrotic tissue. (c) The specificity of the staining was verified by the absence of non-specific staining in negative controls (f, secondary antibody only). S indicates remnants of the repair suture. rAAV, recombinant adeno-associated virus.