FIGURE 3.

Progression of myelination in Lpin1^1Hubr rats. A, toluidine blue-stained semi-thin sections from the medial region of the sciatic nerve of Lpin1^1Hubr and wild-type rats at PND 4, 10, 21, and 90. At PND 4 and 10, the level of myelination is similar in wild-type and mutant nerve. At PND 21 and 90, hypomyelination is visible in sciatic nerves of Lpin1^1Hubr rats compared with wild-type nerves. At PND 90, the general morphology of Lpin1^1Hubr sciatic nerves is improved as compared with the general morphology of sciatic nerves isolated from Lpin1^1Hubr rats at PND 21. B, at PND 4 and 10, average g-ratio, g-ratio trend line, and average axonal diameter of medial sciatic nerve tissue is equal between genotypes. At PND 21 and PND 90, axons of Lpin1^1Hubr rats (MUT) show a decreased axonal diameter as compared with wild-type (WT) axons, and an aberrant g-ratio trend line indicating hypomyelination. Axons of Lpin1^1Hubr rats, however, show an improvement in trend line at PND 90 as compared with PND 21, indicative of partial myelination recovery (PND 4, 10, 21, and 90; n = 2, n = 2, n = 2, and n = 1 per group, respectively; n = 107–374 axons per genotype).