Fig. 2
From: Torpor induces reversible tau hyperphosphorylation and accumulation in mice expressing human tau
Immunohistological analysis of phospho-tau levels in mtau and htau brains (A) Representative coronal slices of eutherm (EU), torpor (T), arousal (A), and 24 post-torpor (24 h) tau−/−, mtau and htau mice, stained with AT8. Brain areas with high AT8 intensity were analysed separately (dashed lines): the hippocampus (HIP), posterior parietal cortex (PPC), piriform cortex (PIR) and cortical amygdala (CoA). (B, C) Quantification of AT8 intensity per area (corrected for mean tau−/− mean gray value) shows a significant increase in tau phosphorylation during torpor for both mtau (B) and htau (C) mice in the total slice and all brain areas (EU vs. TL; p < < 0.05; mtau; total slice: t = 5.739, df = 20; HIP: t = 4.161, df = 22; PPC: t = 6.000, df = 21; PIR: t = 7.485, df = 21 and CoA: t = 5.235, df = 21; htau total slice: t = 6.673, df = 18; HIP: t = 4.744, df = 19; PPC: t = 6.006, df = 19; PIR: t = 6.463, df = 18 and CoA: t = 7.461, df = 18; 1-Way ANOVA, post-hoc Fisher’s LSD for all subsequent tests) which is reversed upon arousal for mtau mice (EU vs. A: p > 0.05) but not yet for htau mice where total slice, PPC, PIR and CoA AT8 intensity remains significantly higher during arousal (EU vs. A, p < 0.05; (total slice: t = 2.277, df = 18; PPC: t = 2.401, df = 19; PIRt = 2.197, df = 18 and CoA: t = 5.163, df = 18). At 24 h post-torpor, AT8 levels are completely reversed for all areas (EU vs. 24 h: p > 0.05; mtau total slice: t = 5.739, df = 20; HIP: t = 4.161, df = 22; PPC: t = 6.000, df = 21; PIR: t = 7.485, df = 21 and CoA: t = 5.235, df = 21; htau total slice: t = 6.673, df = 18; HIP: t = 4.744, df = 19; PPC: t = 6.006, df = 19; PIR: t = 6.463, df = 18 and CoA: t = 7.461, df = 18). 24 h after torpor phospho-tau was significantly lower than in EU for htau mice: 8.972 ± 4.525 vs. 0.1282 ± 1.391, HIP: 10.23 ± 4.919 vs. -1.379 ± 1.079, PPC: 21.21 ± 6.404 vs. 6.215 ± 4.410, PIR: 19.49 ± 9.239 vs. 10.98 ± 4.839 and CoA: 14.95 ± 7.625 vs. 6.962 ± 4.061; p < 0.05 for total slice, HIP and PPC, unpaired student’s t-test. * p < 0.05, ** p < 0.01, *** p < 0.001, **** p < 0.0001)