The level of p21 was enhanced by α-syn PFF exposure in primary cortical neuronal culture for the first 48 h and then it declined gradually. In Western blots, the levels of senescence markers were quantified in the primary cortical neuron at 12, 24, 48 and 72 h after α-syn PFF exposure to detect the expression patterns over time (A). In the analyses of the expression patterns over 3 days of α-syn PFF exposure, the levels of Lamin B1 (B), HMGB1 (C), SATB1 (D) and p21 (F) increased but β-III-tubulin (G) declined over time; however, p16 (E) was not changed significantly. GAPDH was adopted as a loading control, and ImageJ was used for the analyses of band intensities. The relative levels (100% for no PFF treatment) are displayed in mean ± SEM and applied to one-way ANOVA, Dunnett’s post-hoc test (#: compared with T = 0 point) for statistical significance. *: p < 0.05, **: p < 0.01, ***: p < 0.001 and ****: p < 0.0001.