Figure 1. Age-dependent changes in the RTL of cortical neural cell isolates. (A) RTL assessed by Flow-FISH as a function of cell cycle activity. PNA-FITC-related mean fluorescence intensity corrected against background signal (specific MFI) was taken as an indirect parameter for RTL in cells at G0/G1 and G2/M phases of the cell cycle. For both cell populations, a significant age-related reduction in RTL was observed. Bars represent means ± SEM (n = 4 - 8). P-values were assessed with Two-way ANOVA. (B) Cell cycle-independent measurement of RTL assessed by qPCR and determined in terms of a relative T/S-ratio that was referenced against a 4-month-old control group. RTL declined significantly in cortical neural cells of aged as compared to young samples, thus confirming the results obtained in (A). Bars represent means ± SEM (n = 3 - 4). P-values were calculated using the Student’s t-test.