Insulin-Like Growth Factor-1 Regulates Neurite Outgrowth and Neuronal Migration From Organotypic Cultured Dorsal Root Ganglion

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor and plays an important role in promoting axonal growth from neurons. Whether IGF-1 could promote neurite outgrowth and neuronal migration of dorsal root ganglion (DRG) explants in vitro remains unknown. In the present study, organotypic rat DRG explant culture model was established. Using this unique culture system, outgrowth of neurites from the peripheral nerve attached to DRG explant and migration of neurons from DRG explant to the peripheral area were quantified in the presence (5 nmol/L, 10 nmol/L, 20 nmol/L) or absence of IGF-1. The number of nerve fiber bundles extended from DRG explant increased significantly in the presence of IGF-1 (5 nmol/L, 19.25 +/- 3.11, p < .05; 10 nmol/L, 20.92 +/- 2.31, p < .01; 20 nmol/L, 23.00 +/- 4.09, p < .001) as compared with that in the absence of IGF-1 (16.58 +/- 2.94). The number of neurons migrated from DRG explant increased significantly in the presence of IGF-1 (5 nmol/L, 104.08 +/- 16.70, p < .05; 10 nmol/L, 115.25 +/- 13.68, p < .001; 20 nmol/L, 138.75 +/- 18.05, p < .001) as compared with that in the absence of IGF-1 (90.25 +/- 8.53). These data implicated that IGF-1 could promote neurite outgrowth and neuronal migration from DRG explants in vitro.