Figure 7

Requirement of intracellular Ca²⁺ elevation for IGFBPL1 and IGF-1-mediated RGC axonal growth. (A–C), Representative photomicrographs of RGC cultures (A), survival rate (B) and quantification of axon length (C) in cultures treated with PBS or IGFBPL1 + IGF-1 in the absence or presence of Ca²⁺ chelators EGTA or Ca²⁺ channel blocker Nifedipine. Cells and neuronal processes were visualized with Calcein AM. Scale bar: 20 µm. Addition of Ca²⁺ blockers completely abolished RGC axon outgrowth. (D–F) Representative photomicrographs (D), survival rate (E) and quantification of axon length (F) from cultured RGCs treated with PBS or IGFBPL1 + IGF-1 in the presence of a potent L-type Ca²⁺ channel activator FPL64176. Cells and neuronal processes were visualized with Calcein AM. Scale bar: 20 µm. *P < 0.05, as compared to vehicle control treated group by two-tailed student tests; NS: non-significant. Error bars indicate standard error of mean (SEM).