Fig. 4
Cortical TBS- and FA-soluble Aβ42 and their associations with CSF and serum Aβ42/Aβ40 ratios in AppNL−F/NL−F knock-in mice. Cortical TBS- and FA-soluble Aβ42 was measured in 3 (n = 9)-, 6 (n = 7)-, 9 (n = 8)-, 12 (n = 7)-, 16 (n = 8)-, and 18 (n = 9)-month-old AppNL−F/NL−F knock-in mice. A TBS-soluble and D FA-soluble Aβ42 increased in an age-dependent manner with significant changes from 12 and 9 months, respectively. In the whole study population, the Aβ42/Aβ40 ratio in CSF and serum inversely correlated with Aβ42 in the B-C TBS-soluble fraction and the E-F FA-soluble fraction prepared from cortical brain tissue homogenates. Data is presented as median and IQR. Whiskers represent data within 1.5IQR of the lower and upper quartiles. For comparison between groups, statistical analyses were performed using the Kruskal–Wallis H test followed by the Mann–Whitney U test for post hoc group comparisons (**p < 0.01, ***p < 0.001). Correlation analyses were performed using Spearman’s rank-ordered correlation coefficient. Abbreviations: Aβ, amyloid beta; CSF, cerebrospinal fluid; FA, formic acid; IQR, interquartile range; TBS, tris-buffered saline