Paraffin sections from 6.5 month old wild type (A) and Nf1 flox/flox; DhhCre (B) mouse sciatic nerves. Bars in A, B = 50μm. Electron micrograph from wild type (C) and Nf1 flox/flox; DhhCre (D) saphenous nerve. Black arrows in C indicate well organized wild type non-myelinated axons; those in D show disorganized non-myelinated axons. Bars in C, D = 10 microns. (E) Quantification of BrdU positive cells in Nf1 flox/flox; DhhCre P1, P15, and P60 sciatic nerves (white bars) and wild type littermate controls (black bars). Proliferation in the Nf1 flox/flox; DhhCre mouse nerve compared to wild type controls differs significantly in P1 sciatic nerves (p<0.01, n=3) and P15 sciatic nerves (p<0.001, n=3), but not in P60 sciatic nerves (p=0.17, n=3). Data analyzed by Student’s t-test are presented as mean values ± standard deviation. (F) Quantification of apoptotic cells in Nf1 flox/flox; DhhCre P15 sciatic nerves (white bars) and wild type littermate controls (black bars). There is no significant difference in TUNEL staining between Nf1 flox/flox; DhhCre mice and their littermates (p= 0.42, n=4, data analyzed by Student’s t-test are presented as mean values ± standard deviation. A representative image of double staining is shown in I (BrdU: red; P75: green). (G) FACS analysis of BrdU labeled P1/P2 Nf1 flox/flox; DhhCre sciatic nerve cells indicating BrdU+/EGFP+ and BrdU+/EGFP− cells (G, H). (J) Sorted BrdU+/EGFP+ cells are S100β positive (red).