Fig. 3.
APC loss disrupts the radial axonal sorting process in the PNS. The sciatic nerves of Apclox/lox;P0-Cre and control Apclox/lox mice were analyzed morphometrically on Toluidine Blue-stained semi-thin sections (A,B) and by EM (C,D). (A,B) The sciatic nerves of the Apclox/lox;P0-Cre mice contained large bundles of axons compared with control mice. Black arrows indicate bundles of axons. Scale bars: 10 µm. (C,D) Apclox/lox;P0-Cre bundles of axons contained large- and small-caliber axons (D) in contrast to the bundles found in control mice (C) that contained small-caliber axons only. White arrows indicate bundles of axons. Scale bars: 5 µm. (E) The large bundles of axons were ∼3 times larger than the bundles of the control mice at P1, P4, P7 and P14. (F) Apclox/lox;P0-Cre large bundles of axons contained large- and small-caliber axons in contrast to the bundles found in control mice. Box plots show the 25–75% range (box) and 2.5–97.5% range (whiskers). (G) The bundles of unsorted axons in the Apclox/lox;P0-Cre mice contained a higher percentage of large-caliber axons (diameter >1 µm). (H) The density of the axons was not statistically different between Apclox/lox;P0-Cre mice and the control mice at P7. The images in A-D were taken from P7 mice. Axon bundles were analyzed from at least three mice per genotype. Axon diameter was analyzed from at least three mice per genotype at P7. **P<0.001. Large-caliber axons were defined here as axons with diameter of 1 µm and above. Low-caliber axons were defined here as axons with diameter less than 1 µm.