Figure 3. BDNF effects on cell survival.

(a) Fluorescent images of living cells (green, calcein label) and dead cells (red, ethidium homodimer-1 label) in cultures of postnatal day 3 entorhinal cortex neurons in control condition (no Aβ exposure), after addition of Aβ1–42 peptide (Aβ), and after addition of Aβ peptide plus 2.5 ng ml⁻¹ BDNF. Scale bar, 50 µm. (b) Quantification of Aβ42-induced cell death after 24 h in vitro. P < 0.05 by ANOVA, * indicates the difference between the vehicle- and BDNF-treated groups and the Aβ group, P < 0.001 by Fisher’s post hoc test. (c) Perforant path lesion model: GFP immunolabeling in entorhinal cortex at site of lenti-GFP vector injection (left) and BDNF protein production (region of dark immunolabeling) in the same region (right). I–VI indicates cortical laminae. Scale bar, 150 µm. (d,e) Perforant path lesion causes significant loss of Nissl-stained neurons in layer II of the entorhinal cortex (EC) in GFP-injected controls (P < 0.01 versus intact). Nissl stain of layer II entorhinal cortex after perforant path lesions in GFP-injected controls (Lesion-GFP) and BDNF-treated rats (Lesion-BDNF) is shown in d. Stereological quantification of cell number and size after perforant path lesions is shown in e (left, P < 0.05 by ANOVA, *P < 0.01 BDNF versus GFP and NGF by Fisher’s post hoc test; right, P < 0.01 by ANOVA, *P < 0.05 BDNF versus GFP and NGF by post hoc Fisher’s test). Scale bar, 25 µm. (f) pAKT label in entorhinal cortex of treated versus control perforant path–lesioned rats, with stereological quantification at right. Scale bar, 10 µm (*P < 0.001).