FIGURE 3.

sFKN exerts neuroprotective effects in the presence of microglia. A, untreated neuronal cultures (NT; a) and neuron-microglia co-cultures (f; 1:2 neurons to microglia). Glutamate (Glu) induced neuronal loss in both neuronal (b) and neuron-microglia co-cultures (g). Addition of 100 nm sFKN did not significantly increase the survival rate (c), whereas the same treatment significantly increased survival in the presence of microglia (h). Anti-FKN antibody reduced survival of neurons in the neuron-microglia co-cultures (i), but this antibody had no significant effect in neuronal cultures (d). Addition of goat IgG (isotype-matched control for anti-FKN antibody) had no effect on the survival rate (e and j). Neurons were stained with anti-MAP-2 antibody (green), and microglia were stained with a Cy5-conjugated anti-CD11b antibody (red). Scale bar = 50 μm. B, neuronal survival was estimated as the percentage of intact neurons in the sample relative to the untreated sample. The columns indicate the mean ± S.E. from three independent experiments. In each experiment, 10 randomly selected fields were analyzed. *, indicates significant differences compared with Glu treatment (*, p < 0.05; ***, p < 0.001; n.s., not significant).