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Figure 4
Cell death is severity-dependent and radiates out from the impact zone as a gradient. (A?D) Brightfield images of coronal cerebellar (CCe) sections stained with DAB-TUNEL 16 hpi. Prominent DAB TUNEL-positive cells were observed in the CCe in a severity-dependent manner. (E) Quantification of the number of DAB-TUNEL-positive cells/section revealed significant increases in the number of TUNEL-positive cerebellar cells following moTBI and sTBI (n = 8). (F?O?) Confocal images of coronal sections, from rostral to caudal across the neuroaxis, stained with fluorescent TUNEL and DAPI-labeled at 16 hpi (J?O). Apoptotic cell death, emanating from the impact zone, was observed widely across the neuroaxis. The red box in panel A shows the relative position of the image on the appropriate brain cross-section. Solid lines denote tissue boundaries, while dotted lines denote internal anatomic boundaries. Cerebellar crest, CC, corpus cerebelli, CCe, diencephalic ventricle, DiV, granule cell layer, GL, molecular layer, ML, medulla oblongata, MO, parenchyma, Paren, periventricular grey zone, PGZ, optic tectum, TeO, torus longitudinalis, TL, rhombencephalic ventricle, RV, medial valvula cerebelli, Vam, lateral valvula cerebelli, Val. Scale bars: (A) = 100 µm, for panels (A?D,F) = 200 µm, for panels (F?I?,J) = 500 µm, for panels (J?O?,J?) = 200 µm, for panels (J??M?,N?) = 100 µm, for panels (N?,O?). Mean ± SEM is depicted in (E). Statistical analyses were performed with a One-way ANOVA followed by a Tukey?s post-hoc test. ## p < 0.01.