Figure 3.

Aβ_1-42 induced toxicity and enhancement of active caspase 3 in nondifferentiated and differentiated mOP cells. Phase contrast photomicrographs of nondifferentiated (A) and differentiated cells (B) are depicted. The insets are digitally magnified to 60% the original image to illustrate bipolar morphology of nondifferentiated cells (C) and multiprocess mature morphology on differentiated cells (D). Nondifferentiated and differentiated cells were stained using CNPase (E and G, respectively) and MBP (F and H, respectively) to determine the maturation stages of the cells. mOP cultures were subsequently treated with 0–4 μmol/L Aβ_1-42 and Aβ_42–1 peptides for four hours. mOP cell death was determined using Hoecsht 33342 staining for both nondifferentiated (I) and differentiated cells (J). Immunocytochemistry for active caspase 3 was performed on fixed mOP cells, and representative images for nondifferentiated and differentiated cells are depicted (K and L, respectively). Arrowheads point to active caspase-3–positive cells. Quantification of active caspase-3 positive mOP cells was performed for both nondifferentiated (M) and differentiated (N) cultures. An average of 1000–5605 cells were enumerated per condition (N = 4) per experiment. A total of three and two independent experiments were performed, respectively. Scale bars = 5 μm. Error bars indicate SD. *P < 0.05; ***P < 0.001.