Fig. 3.

OPC migration as a function of the distance from semaphorins and netrin-1 secreting cells. ON explants were confronted to control cells (A), netrin-1 (B), Sema 3A (C), Sema 3C (D), Sema 3E (E), or Sema 3F (F) secreting cells. To examine whether the amount of cell migration was dependent on the concentration of secreted factor available, a correlation (r, Pearson's correlation coefficient; p, statistical significance of the test) was established between the number of cells migrating out from ON explants and the distance between the ON explant and the source of secreted factor. The correlation is significant only for Sema 3C and Sema 3F (p < 0.05), which suggests that both factors might have a trophic effect on OPCs.