Delayed upregulation of cell cycle proteins and GFAP is suppressed by cell cycle inhibition. (A) Coronal section in intact spinal cord showed that cyclin D1 was mostly expressed in the gray matter (a). Cyclin D1 immunoreactivity at 4 months after injury was increased in the spared white matter surrounding the central lesion at 1 mm caudal to the epicenter (b), whereas this was attenuated by treatment with CR8 (c). GFAP immunoreactivity was weak in sham (d), but was strongly upregulated at 4 months post-injury (e). CR8 reduced expression of cyclin D1 (c) and GFAP (f), and their co-localization (i). (B) In the intact spinal cord, immunoreactivity of cyclin E (a), CDK4 (b) and E2F5 (c) was weakly detected in neurons across the gray matter. SCI resulted in increased expression of cyclin E (d), CDK4 (e) and E2F5 (f) at the site of the injury, which were attenuated in CR8-treated sections (g-i). Scale bars = 500 μm.