Figure 5

(a) Scores of the Principal component analysis (PCA) using the second derivative of the amide I region of infrared spectra showing data from WT mice, APP/PS1 mice 6 months old and APP/PS1 6 months old treated with G4-His-Mal dendrimers. WT data is shown in red, APP/PS1 data in grey and APP/PS1 treated with G4-His-Mal dendrimers in blue. The loadings corresponding to the PCA scores corresponding to the mice treated with G4-His-Mal- dendrimers are depicted in Fig. S1 together with the PCA scores of the whole set of data used in this study; (b) normalized mean second derivative of the amide I region calculated from the individual spectra of the data points within the colour circle/rectangle in the outlier regions of the PCA scores. The bottom row shows the box plot graphics depicting the absorbance ratio values corresponding to the two different types of aggregated species calculated from the second derivative spectra of the data points within the colour circle/rectangle in the outlier regions of the PCA scores. Fibrillary aggregates are shown in (c) and oligomeric/granular aggregates in (d). Boxplot shows the median (center line), interquartile range (IQR) (box); whiskers represent the most extreme data located no more than 1.5xIQR from the edge of the box, and outliers are the points outside this range. T-test is used for comparison with WT (red*) and 6 months mice (*black) at p < 0.002. Colour code: each set of point in the box plots has the same colour as the circle with which the data points from which the ratios have been marked in the scores plot. Unscrambler X software (CAMO, Oslo, Norway) was used to perform PCA and Origin 9.1 and Microsoft power point 2016 software were used for graphical representation.