Fig. 6

Inhibition of TGFβ signaling alters perineurial glial bridging dynamics. (a) Representative image of a recently transected spinal motor nerve in a 6 dpf nkx2.2a:megfp larva with the proximal (green dot) and distal (magenta dot) stumps labeled. (b,c) Representative images from tracking of both the proximal (green dot) and distal (magenta dot) stumps from time-lapse movies of perineurial glia in injured 5 or 6 dpf larvae treated with either 1% DMSO (b) or 10 μM SB431542 (c). (d–i) Quantification of the average velocity of perineurial glial membrane proximal or distal stumps in μm/s plotted over time (d–f) or for the first 200 min post injury (mpi) (g–i). Velocities were calculated every 5 min using FIJI. Each dot represents the average velocity of all larvae within a group at that specific time point. (d,g) There is no significant difference in proximal only perineurial glial bridging velocity between DMSO and SB431542-treated larvae (mean: 0.116 ± 0.02 μm/s, 0.063 ± 0.015 μm/s, respectively; p = .1078) (n = 3 nerves in 3 larvae, n = 3 nerves in 3 larvae, respectively). (e,f,h,i) There is a significant difference in perineurial glial bridging velocity between DMSO and SB432542-treated larvae, with DMSO-treated larvae having a higher average velocity, (n = 4 nerves in 3 larvae, n = 3 nerves in 3 larvae, respectively) in both proximal (mean: 0.139 ± 0.03, 0.08 ± 0.02 μm/s, respectively; p < .0001) and proximal and distal (mean: 0.18 ± 0.03, 0.06 ± 0.02 μm/s; p < .0001) bridging in larvae that had bridging from both the proximal and distal perineurial glial ends. Scale bars, (a) 25 μm; (b,c) tracking images, 10 μm.