FIG. 3.

Live imaging of GFP axons highlights differences in regeneration. (A) Fluorescent images of Thy1-GFP axons at the end of the 8-week recovery period for the control and experimental conditions are shown. By the end of the recovery period, regeneration of GFP⁺ axons past the graft area can be observed clearly in the isograft control group. The GDNF-DS group also indicates distal growth of GFP⁺ axons, but regeneration appears greatly reduced in the ANA group and slightly reduced in the control vector-SC group. When doxycycline was removed too early at 4 weeks or continued for the entire 8 weeks (with or without the GDNF-DS), GFP⁺ axons become entrapped within the graft. Only 6 weeks of doxycycline show GFP⁺ axons past the distal suture line. White arrowheads denote start and end of graft region. Scale bar = 3 mm. *denotes statistical significance from all other groups. (B) Average length of GFP⁺ axons over the 8-week recovery period is shown. Isografts had significantly greater length of GFP fluorescence over time. Only at 8 weeks does is stand out that DS ANA and GDNF-SCs DS Dox6 promoted greater GFP⁺ axon extension into the grafts. Data are represented by the mean ± SEM. ^ denotes significance from GDNF-SCs DS Dox6 (p < 0.05). (C) Length of GFP⁺ axons was normalized to the length of the grafts as the grafts can shrink over time. The dotted line at 1 marks the growth of GFP⁺ axons at graft length and clearly identifies groups in which axons become entrapped within the graft. Color images available online at www.liebertpub.com/tea