Figure 2.

Propidium Iodide staining in 1-week-old cortical neuronal cultures. 1-week-old cortical neuronal cultures were challenged by TFW. At various time points following TFW challenge, culture plates were exposed in vitro to Propidium Iodide. The fluorescent signal from the DNA intercalating dye was imaged and stored for off line analysis. Panels A, B and C are representative images from WT, Aβ40 and Aβ42 cortical neurons respectively after 1 week of culture and under basal conditions of TFW challenge. Panels D, E and F are corresponding images at 24 hours post-TFW challenge. In D, E and F, arrowheads identify typical morphology of “speckled” or “rough” staining of nuclei and are markers for DNA fragmentation. The right half of the figure is a bar plot showing the fraction of cells (% of total counted in all fields) that had this “fragmented” morphology. WT are compared with Aβ40 and Aβ42. WT neurons had 4% fragmentation while Aβ40 exhibited 48% and Aβ42 displayed 45% speckling or fragmentation. Both transgenic groups had a statistically significant result when compared with WT (p = <0.05). However, when the transgenic neurons were compared with each other, no statistical significance was observed.