Figure 5
Decreased SCI-associated OL loss in Bmal1−/− mice. (a) SCI WT and Bmal1−/− mice were as described for Fig. 4a (n = 5/genotype). Naïve WT controls received the same treatment as SCI mice except surgery and were killed after 3 days (n = 5, M:F = 2:3). Expression of mRNAs specific for OLs or neurons was analyzed by qPCR. Both OL and neuronal markers declined at dpi 3, indicating acute loss of those cells. Similar declines in WT and Bmal1−/− mice suggest no effects of the Bmal1−/− genotype on acute loss of OLs or neurons. (b–d) SCI WT and Bmal1−/− mice were as described for Fig. 4b (WT M:F = 2:3 including 3 KO littermates, Bmal1−/− M:F = 1:3). At dpi 42, after completion of the last BMS evaluation, mice were sacrificed. Transverse sections were co-immunostained to detect OLs (CC1) and axons (anti-NFH); cell nuclei were counterstained with Hoechst-33258. (b) Representative images of that staining in the ventral WM. (c) In the ventral and ventrolateral WM at the injury epicenter, the decline of OL density (CC1+/Hoechst+ cells) was attenuated in Bmal1−/− mice suggesting reduced chronic loss of OLs (RM ANOVA, factor: genotype, F1,7 = 10.245 or 26.026, p < 0.05 for ventral or ventrolateral WM, respectively). (d) Relative axonal density (defined as NFH staining area to Hoechst staining area normalized to WT) was unaffected. (RM ANOVA, factor genotype, F1, 7 = 0.0786 or 0.123, p > 0.05 for ventral or ventrolateral WM, respectively). Data in (a, c, d) are means ± SD (*p < 0.05; **p < 0.01, ns, p > 0.05, u-test in (a), Tukey post-hoc tests in (c, d).
