HFD after finishing exercise promoted APP CTFβ accumulation in APP-HFD mice.

<p>(<i>A</i>) Immunoblotting analysis of APP full length and APP-CTFβ using APP C-terminus antibody. The number of animals used for immunoblotting analysis is 3–4 per group. Statistical analysis is shown in the right panel. The band of APP CTFβ was normalized by that of APP full length. The band density of the control APP mice was regarded as 100% and that of other groups was relatively indicated. The band density of APP CTFβ in APP-HFD+Ex 0–10 mice tended to be higher compared with that in APP-HFD+Ex 10–20 mice (F _{(4, 13)}  = 3.70, p = 0.070). * indicated p<0.05. (<i>B</i>) <i>In vitro</i> enzyme activity assay of neprilysin using fluorescent substrate. The activity of neprilysin in APP-HFD+Ex 0–10 or APP-HFD+Ex 5–15 mice was not different from that in APP-HFD+Ex 10–20 mice (F _{(4, 15)}  = 4.10). * indicated p<0.05.</p

Effect of exercise on memory function was abolished by HFD in APP transgenic mice.

<p>(<i>A</i>) The time to get to goal platform of exercise-treated WT-HFD mice (upper) and APP-HFD mice (lower) in the acquisition phase of Morris water maze test, 20 weeks after having HFD. WT-HFD+Ex 0–10 mice and WT-HFD+Ex 5–15 mice took the same time to get to the platform as WT-HFD+Ex 10–20 mice. Also, APP-HFD+Ex 0–10 mice and APP-HFD+Ex 5–15 mice tended to take longer than APP-HFD+Ex 10–20 mice to get to the platform; however, this was statistically insignificant. (<i>B</i>) Time taken to get to goal position of exercise-treated WT-HFD mice (left) and APP-HFD mice (right) in the probe trial phase of Morris water maze test, 20 weeks after having HFD. WT-HFD+Ex 0–10 mice (F _{(4, 10)}  = 18.63, p<0.001) and WT-HFD+Ex 5–15 mice (p<0.001) took less time to reach the platform position than WT-HFD mice, but they took the same time as WT-HFD+Ex 10–20 mice. On the other hand, APP-HFD+Ex 0–10 mice (F _{(4, 20)}  = 7.89, p<0.001) and APP-HFD+Ex 5–15 mice (p = 0.006) took longer to get to platform position than APP-HFD+Ex 10–20 mice. The time taken by APP-HFD+Ex 0–10 mice and APP-HFD+Ex 5–15 mice was the same as that by APP-HFD mice. * indicated p<0.05. (<i>C</i>) Time in goal quadrant of exercise-treated WT-HFD mice (left) and APP-HFD mice (right) in the probe trial phase of Morris water maze test, 20 weeks after having HFD. WT-HFD+Ex 0–10 mice (F _{(4, 10)}  = 46.97, p<0.001) and WT–HFD+Ex 5–15 mice (p<0.001) spent more time in goal quadrant than WT-HFD mice, but spent the same time in goal quadrant as WT-HFD+Ex 10–20 mice. On the other hand, APP-HFD+Ex 0–10 mice (F _{(4, 20)}  = 7.09, p = 0.003) and APP-HFD+Ex 5–15 mice (p = 0.003) spent less time in goal quadrant than APP-HFD+Ex 10–20 mice. The time for APP-HFD+Ex 0–10 mice and APP-HFD+Ex 5–15 mice was the same as that for APP-HFD mice. * indicated p<0.05.</p

HFD after exercising increased Aβ oligomer as well as deposited Aβ levels in APP-HFD mice.

<p>(<i>A</i>) Immunohistochemical analysis using anti-Aβ (6E10) antibody. Representative images of Aβ-immunostained hippocampus sections from control APP, APP-HFD, APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice, respectively. Scale bar, 0.5 mm. Increase of Aβ deposition was observed in APP-HFD+Ex 0–10and APP-HFD+Ex 5–15 mice compared with that in APP-HFD+Ex 10–20 mice. However, the amount of Aβ deposition in APP-HFD+Ex 0–10 mice and APP-HFD+Ex 5–15 mice was less than that in APP-HFD mice. (<i>B</i>) The amount of Aβ 40 in FA fraction of control APP, APP-HFD, APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice was analyzed by ELISA. Aβ 40 level in FA fraction of APP-HFD+Ex 0–10 mice was higher than that of APP-HFD+Ex 10–20 mice (F _{(4, 15)}  = 10.40, p = 0.009). However, the amount of Aβ 40 in APP-HFD+Ex 0–10 mice (p = 0.028) and APP-HFD+Ex 5–15 mice (p = 0.004) was less than that in APP-HFD mice. * indicated p<0.05. (<i>C</i>) The amount of Aβ 42 in FA fraction of control APP, APP-HFD, APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice was analyzed by ELISA. There was no statistically significant difference in the level of Aβ 42 among APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice (F _{(4, 15)}  = 24.4). However, the amount of Aβ 42 in APP-HFD+Ex 0–10 mice (p<0.001) and APP-HFD+Ex 5–15 mice (p<0.001) was lower than that in APP-HFD mice. * indicated p<0.05. (<i>D</i>) The amount of Aβ oligomer in the TBS-soluble fraction of control APP, APP-HFD, APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice was analyzed by ELISA. The level of Aβ oligomer in TBS fraction of APP-HFD+Ex 0–10 mice was higher than that of APP-HFD+Ex 10–20 mice (F _{(4, 15)}  = 3.33, p = 0.035). The amount of Aβ oligomer in APP-HFD+Ex 0–10 mice was the same as that in APP-HFD mice. * indicated p<0.05. (<i>E</i>) The amount of Aβ oligomer in the TBS-soluble fraction of control APP, APP-HFD, APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice was analyzed by filter trap assay using anti-oligomer (A11) antibody to detect oligomeric Aβ. Representative images of dot are shown in upper panel. Statistical analysis of dot density is described at the bottom. The average dot density of the control APP samples was regarded as 100% and that of other groups was relatively indicated. The relative density of APP-HFD+Ex 0–10 mice was higher than that of APP-HFD+Ex 10–20 mice (F _{(4, 10)}  = 12.69, p = 0.007). The dot density of Aβ oligomer in APP-HFD+Ex 0–10 mice was the same as that in APP-HFD mice. * indicated p<0.05.</p

HFD after finishing exercise deteriorated glucose tolerance in APP-HFD mice.

<p>(<i>A</i>) Relative body weight changes over 20 weeks in control APP, APP-HFD, APP-HFD+Ex 0–10, APP-HFD+Ex 5–15 and APP-HFD+Ex 10–20 mice. The body weight 2 weeks before each diet was regarded as the baseline (0 g). (<i>B</i>) Blood glucose levels during glucose tolerance test after an intra-peritoneal injection of glucose (2 g/kg body weight). Fasting glucose levels in APP-HFD+Ex 0–10 mice (F _{(4, 20)}  = 9.03, p<0.001) and in APP-HFD+Ex 5–15 mice (p = 0.006) were higher than those in APP-HFD+Ex 10–20 mice. Glucose tolerance abilities in APP-HFD+Ex 0–10 mice (F _{(4, 60)}  = 16.17, p<0.001) and in APP-HFD+Ex 5–15 mice (p<0.001) were worse than those in APP-HFD+Ex 10–20 mice. The glucose tolerance in APP-HFD mice was the same as those in APP-HFD+Ex 0–10 mice and APP-HFD+Ex 5–15 mice. n.s. indicated not significant. * indicated p<0.05. (<i>C</i>) Blood insulin levels during fasting. Plasma insulin levels in APP-HFD+Ex 0–10 mice and in APP-HFD+Ex 5–15 mice were not different from those in APP-HFD+Ex 10–20 mice (F _{(4, 20)}  = 2.22). * indicated p<0.05. (<i>D</i>) Average running distance using a running wheel per day (m/day). Running distance was estimated from the number of running wheel rotations. The lengths in APP-HFD+Ex 0–10 mice (F _{(2, 12)}  = 7.61, p = 0.003) and in APP-HFD+Ex 5–15 mice (p = 0.008) were significantly longer than those in APP-HFD+Ex 10–20 mice. * indicated p<0.05. (<i>E</i>) Relative body weight changes over 20 weeks in control WT, WT-HFD, WT-HFD+Ex 0–10, WT-HFD+Ex 5–15 and WT-HFD+Ex 10–20 mice. The body weight 2 weeks before each diet was regarded as the baseline (0 g). (<i>F</i>) Blood glucose levels during glucose tolerance test after an intra-peritoneal injection of glucose (2 g/kg body weight). Fasting glucose levels in WT-HFD+Ex 0–10 mice (F _{(4, 10)}  = 12.72, p = 0.006) and in WT-HFD+Ex 5–15 mice (p<0.001) were higher than that in WT-HFD+Ex 10–20 mice. Glucose tolerance abilities in WT-HFD+Ex 0–10 mice (F _{(4, 30)}  = 29.98, p<0.001) and in WT-HFD+Ex 5–15 mice (p<0.001) were lower than that in WT-HFD+Ex 10–20 mice. n.s. indicated not significant. * indicated p<0.05. (<i>G</i>) Insulin levels during fasting. Insulin levels in WT-HFD+Ex 0–10 mice and in WT-HFD+Ex 5–15 mice were not different from that in WT-HFD+Ex 10–20 mice (F _{(4, 10)}  = 7.24).</p