Figure 1.
Glial scar formation visualized by GFAP-immunofluorescence in MMP-9 null and wild-type mice. A moderate reactive astroglial border is formed between the GFAP-quiescent area in the lesion epicenter (asterisks) and the intact tissue 14 d post-injury (A, B; horizontal sections). The pattern of glial scarring appears similar between the MMP-9 null and wild-type mice. At 42 d postinjury, however, the wild-type mouse exhibits a more severe glial scar formation in the lesion, evidenced by intricate tangling of astrocytic processes and intense GFAP immunoreactivity, than the MMP-9 null mouse (C, D; transverse sections). At higher magnification (E, F; taken from boxed area in C and D, respectively), entangled astrocytic processes are densely bundled to form a robust trabecular meshwork in the wild-type mouse, whereas the glial scarring is relatively modest in MMP-9 null mouse. The sampling strategy used in our semiquantitative analysis of the glial scar is illustrated in the diagram (G). Scale bars: A, B, E, F, 100 μm; C, D, 250 μm.