Fig 6. Morphometric properties of GFAP-immunoreactive astrocytes reveal effects of and interactions between brain slice incubation time and overpressure exposure.

(A) Average branch order is reduced by 1 hr post-testing but not in control slices from a sample of GFAP+ astrocytes selected for isolation (non-overlapping) and full containment in confocal image stacks. A relative reduction in branch order defining a overpressure effect was evident in overpressure slice cells until 3 hours, after which cells in both groups exhibited few branches beyond primary.(B, C, D) Blast and incubation time have coordinated effects on numbers of branch points, branches, and branch tips. (E) Branches emerging from cell bodies are not affected by overpressure at any time point, or incubation before 4 hrs. (F) Individual branch length comprised of stems and tips was not affected by overpressure or incubation time. (G) Difference in inter-branch segments was not significant between the two treatment groups. (H) Reduction in total length of branches per cell was substantial and progressive with overpressure and time, with essentially total elimination in the 4 hr overpressure sample. (I) An accompanying increase in average compartment lengths suggests either straightening of branches or loss of tortuous processes [44]. A small but significant effect of overpressure is observed at early time points. (J) Average arbor height (distance from soma to most distal tip) was reduced early and progressively by shock, compared to relative stability in controls before 4 hrs. Asterisks reflect p < 0.05 in post-hoc comparisons between adjacent conditions; significant main effects and interactions are summarized in Table 2.