Figure 2.

Neuroprotective effect of IGF-I (Upper) and IGF-II (Lower) against Aβ_25–35-induced toxicity in rat primary hippocampal neurons. Aβ_25–35 alone (30 μM), induced a marked loss in MTT values down to 44% of controls. Concentration-dependent neuroprotective effects of IGF-I and IGF-II are observed against Aβ_25–35 toxicity when the trophic factors are added simultaneously with Aβ_25–35. Increasing concentrations of IGFs, by themselves, failed to have significant effects in control cultures (dashed lines). IGF-I was clearly more effective than IGF-II. ∗, P < 0.01 as Aβ-treated neurons.