Table 1.
Strain background of rTg4510 mice used in this study.
Fig 1.
Chemical structures of curcumin and Shiga-Y5.
Shiga-Y5 (B) is a curcumin (A) derivative bearing a methoxycarbonylethyl group and a trifluoromethoxy groups.
Table 2.
Summary of statistical analysis in behavioral assessment.
Fig 2.
Behavioral assessment in rTg4510 mice.
(A, B) Motor activity and learning were assessed using rotarod test with low (A) and high (B) speed settings. (C, D) Spontaneous alteration (C) and total number of entries (D) in Y-maze test was used to evaluate spatial short-term memory and exploratory activity, respectively. (E, F) Morris water maze test consisted of 5 training trials per day over 6 consecutive days (E) and probe test on day 7 (F). Wild-type mice fed with control chow diet (n = 8) and Shiga-Y5 (SY5)-containing chow diet (n = 8), and rTg4510 mice fed with control chow diet (n = 8) and SY5-containing chow diet (n = 7) were subjected to behavioral tests. According to the results of cued navigation test in Morris water maze test, one rTg4510 mouse fed with control chow diet was excluded from the results. Data are the mean ± standard of the mean. (A-F) Significance [Tukey multiple comparisons test after two-way ANOVA (genotyping x treatment)]: *p < 0.05, **p < 0.01, ***p < 0.001 vs. wild-type mice fed with control chow diet. (E) Significance (Tukey multiple comparisons test after repeated-measures one-way ANOVA): †††p < 0.001 vs. day 1.
Fig 3.
Tau pathology in the cerebral cortex in rTg4510 mice.
Representative photographs showing the immunohistochemistry for AT8 (A-D) and Gallyas silver staining (E-H) in the cerebral cortex in rTg4510 mice fed with control chow diet (A, B, E, F) and Shiga-Y5 (SY5)-containing chow diet (C, D, G, H). Images of left and right columns were from rTg4510_TxC mice and rTg4510_CxT mice, respectively. Scale bars: 500 μm.
Fig 4.
Tau pathology in the hippocampus in rTg4510 mice.
Representative photographs showing the immunohistochemistry for AT8 (A-D) and Gallyas silver staining (E-H) in the hippocampus in rTg4510 mice fed with control chow diet (A, B, E, F) and Shiga-Y5 (SY5)-containing chow diet (C, D, G, H). Images of left and right columns were from rTg4510_TxC mice and rTg4510_CxT mice, respectively. Scale bars: 500 μm.
Fig 5.
Quantification of the levels of tau pathology in rTg4510 mice.
(A-D) AT8-mmunoreactive area (A, C) and Gallyas positively staining area (B, D) in the cerebral cortex (A, B) and hippocampus (C, D) in rTg4510 mice fed with control chow diet (n = 8) and Shiga-Y5 (SY5)-containing chow diet (n = 7) were analyzed. (E-H) The levels of AT8 (E, G) and Gallyas positive area in the cerebral cortex (A, B) and the hippocampus (C, D) were also analyzed in rTg4510_TxC mice fed with control chow diet (n = 4) and rTg4510_CxT mice fed with control chow diet (n = 4). Data are the mean ± S.E.M. Significance (Mann Whitney test): *p < 0.05 vs. rTg4510_TxC mice.
Fig 6.
TBS-soluble tau levels in rTg4510 mice.
(A, D) Representative western blot images for tau and β-actin in the cerebral cortex (A) and the hippocampus (D). Left and right bands in each group correspond to rTg4510_TxC mice and rTg4510_CxT mice, respectively. (B, C, E, F) Densitometric analysis of the levels of tau and AT8-positive phosphorylated tau in the cerebral cortex (B, C) and the hippocampus (E, F) in rTg4510 mice fed with control chow diet (n = 8) and Shiga-Y5 (SY5)-containing chow diet (n = 7). Data are the mean ± standard error of the mean. Significance (Mann Whitney test): *p < 0.05.
Fig 7.
Sarkosyl-insoluble tau accumulation in rTg4510 mice.
(A, D) Representative images in western blotting for tau and AT8 in the cerebral cortex (A) and the hippocampus (D). Left and right bands in each group correspond to rTg4510_TxC mice and rTg4510_CxT mice, respectively. (B, C, E, F) Densitometric analysis of tau (B, E) and AT8-positive tau (C, F) levels in the cerebral cortex (B, C) and the hippocampus (E, F) in rTg4510 mice fed with control chow diet (n = 8) and Shiga-Y5 (SY5)-containing chow diet (n = 7). Data are the mean ± standard error of the mean.
Fig 8.
Soluble and insoluble tau levels in rTg4510 mice_TxC and rTg4510 mice_CxT.
The levels of tau (A, C, E, G) and AT8-immunopositive phosphorylated tau (B, D, F, H) in the TBS-soluble (A, B, E, F) and sarkosyl-insoluble (C, D, G, H) fractions in the cerebral cortex (A-D) and the hippocampus (E-H) were analyzed in rTg4510_TxC mice fed with control chow diet (n = 4) and rTg4510_CxT mice fed with control chow diet (n = 4). Data are the mean ± standard error of the mean. Significance (Mann Whitney test): *p < 0.05, **p < 0.01.