Conditional Deletion of Pten Leads to Defects in Nerve Innervation and Neuronal Survival in Inner Ear Development
Figure 4
Reduction in neuronal cell number in the cochleovestibular ganglia (CVG) of Pten conditional knockout (cKO) mice.
(A) NeuroD-positive cells are shown in green, and Islet1-positive cells are in red. Early matured neurons appeared to be expressed by both Islet1-positive and NeuroD-negative cells in the CVG at E10.5 (arrow in e, f). CVG, cochleovestibular ganglion; GG, geniculate ganglion; OV, otic vesicle. Scale bar: 100 µm. (B–D) Cell counts in the CVG (white outlines in A) and epithelium at E10.5. (B) The number of NeuroD-positive cells in Pten-deficient mice was reduced markedly to about half of that in wild-type mice (5 cochleae, P<0.001). (C) A significant reduction in NeuroD-positive cells in the inner ear epithelium was observed in Pten cKO mice (8 cochleae, P<0.05). (D) Early differentiated neurons expressed by Islet1-positive/NeuroD-negative in Pten-deficient mice showed a significant loss compared to those in wild-type mice (6 cochleae, P<0.05).