FIG. 4.

Lateral traumatic brain injury (TBI) caused time- and region-dependent changes in serine 3-phosphorylated cofilin (pSer3-cofilin) immunoreactivity. The ipsilateral and contralateral hemispheres of the hippocampus and neocortex were dissected from post-TBI rats and their age-matched controls, separately homogenized, and subjected to immunoblotting with antibodies recognizing pSer3-cofilin. The results indicated significant changes in pSer3-cofilin immunoreactivity following lateral TBI, relative to controls. In the ipsilateral hippocampus, for example, pSer3-cofilin decreased significantly at 24 h post-TBI, increased at 2 weeks post-TBI, but then decreased again at 4 weeks post-TBI, relative to controls (A). The contralateral hippocampus also underwent an acute decrease in pSer3-cofilin immunoreactivity at 1 h, 12 h, and 24 h post-TBI, compared to controls (B). The neocortex showed a different pattern of changes in pSer3-cofilin immunoreactivity, with an increase at 1 h post-TBI, followed by decreases at subsequent time points, in both the ipsilateral neocortex (C), and contralateral neocortex (D), relative to controls. Specifically, pSer3-cofilin immunoreactivity decreased below control levels at 12 h post-TBI and all later time points in the ipsilateral neocortex (C), and at 24 h and 4 weeks post-TBI in the contralateral neocortex (D). All comparisons were made by one-way analysis of variance with Dunnett's post-hoc test (*p<0.05, **p<0.01).