Fig. 2

GDF5 acts locally on axon terminals to promote axon growth. a Schematic illustration of the two-chamber microfluidic device. The inset shows a neuron with its cell body in the soma compartment on the left extending its axon arbor through a microchannel into the axon compartment on the right. b-d Photomicrographs of representative P0 SCG neurons cultured in defined medium for 24 h with 10 ng/ml NGF in both compartments (b), NGF in both compartments plus 10 ng/ml GDF5 in the axonal compartment (c) and NGF in both compartments plus 10 ng/ml GDF5 in the soma compartment (d). Scale bar = 200 μm. e Bar chart of axon length measurements in the axon compartment (*** P < 0.0001, statistical comparison with NGF alone, ANOVA)