(Fig.4D–F).4D–F). Furthermore, the proportion of GFAP and Pax6 double-positive expressing cells increased significantly after Fgf2 treatment (Fig. (Fig.4G–H).4G–H). Some of these cells possessed bipolar (Fig. (Fig.4G,4G, lower
panel) rather than the multipolar morphology of reactive astrocytes in PBS-control (Fig. (Fig.4G,4G, upper panel). Furthermore, many of the Pax6-positive cells do not colabel with CSPGs after Fgf2 treatment, suggesting that these cells lose the characteristics #selleck chemicals Carfilzomib keyword# of reactive astrocytes (Fig. (Fig.44I–K). Fgf2 mediates glial bipolar morphology at the further information lesion site to support neurite elongation and axonal regeneration In control animals at 7 weeks post-SCI (with two first week of Fgf2/PBS treatment), reactive GFAP-positive astrocytes formed a glial scar, characterized by dense networks of processes around and at the lesion
7 weeks Inhibitors,research,lifescience,medical post-SCI. Although β-tubulin–labeled neurites are present within the lesion, they do not extend through the dense network of glial processes Inhibitors,research,lifescience,medical (Fig. (Fig.5A5A and A′). Fgf2 treatment for the first 2 weeks after injury induced a bipolar morphology within GFAP-positive cells, enabling neurites from neighboring neurons to grow along elongated glial processes, and consequently long β-tubulin–labeled can be seen extending through the lesion site (Fig. (Fig.5B5B and B′). Although gliosis and overall GFAP expression is lower in the Fgf2-treated mice, more of the GFAP-positive processes contribute to these parallel bridges (Fig. (Fig.5A5A and B). We saw the same result 4 months
after SCI (Fig. (Fig.5C5C and D). These results are similar to what previously has been seen in zebrafish Inhibitors,research,lifescience,medical Inhibitors,research,lifescience,medical (Goldshmit et al. 2012) and suggests that Fgf2 drives changes in glial morphology to bridge the gap of the lesioned area and support neurite regeneration through the lesion. To test this we next investigated the effect of Fgf2 treatment on regeneration of descending neuronal tracts. To undertake this analysis, we injected the anterograde tracer TMRD at 6 weeks or 4 months postinjury, at the cervical level, upstream of the lesion Cilengitide of the 2-week treatment group. Treatment with Fgf2 resulted in a significant increase in the number of axons upstream to the lesion site 7 weeks after injury (Fig. (Fig.6A–C;6A–C; 100 μm upstream to the lesion). Additionally, a small proportion of axons entered and started to cross the injury site in Fgf2-treated mice only (Fig. (Fig.6B6B and B′). Triple labeling showed that astrocyte processes (GFAP positive) of proliferative cells (BrdU positive) were often aligned parallel to and along regenerating axons (tracer labeled) in Fgf2-treated animals in contrast to processes in PBS-control mice, which were oriented more randomly (Fig. (Fig.6D6D and E arrowheads).