Figure 2. HBOT reduces the population of newly-formed plaques and reduces the volume of pre-existing plaques. Amyloid plaques were visualized in vivo using two-photon microscopy imaging in live animals by injecting methoxy-X04 24 h before every imaging session. (A) Representative images of plaques in the somatosensory cortex of HBO-treated 5XFAD (n=4, right panel) and control 5XFAD mice (n=3, left panel) before (upper panel) and after 1 month of treatment (lower panel); red circles indicate the change in specific plaques, scale bar: 50 μm. (B) Analysis of the volume of pre-existing plaques before and after each treatment in the same animal, categorized according to initial plaque size. (C, D) Distribution of plaque populations by volume in control 5XFAD (C; before: N=1619, after: N=3180) and HBO-treated 5XFAD mice (D; before: N=3425, after: N=3524). Two-way ANOVA with repeated measures and post-hoc Fisher LSD tests were performed. Values represent means ± SEM. *P < 0.05, *** P < 0.001, **** P < 0.0001.