Figure 7.

Myelination begins in utero in naked mole-rat but not mice. (A) Artificial immunoblots were generated with capillary electrophoresis by probing naked mole-rat (NMR) brain homogenates with antibodies directed against myelin associated glycoprotein (MAG) and myelin basic protein (MBP). Each isoform was normalized to β-actin. (B) Densitometric values were calculated by normalizing to β-actin loading control. Statistical analyses reveal significant changes during the first 3 years of life for both proteins (ANOVA, p < 0.0001 for both). MAG levels increase significantly from nearly undetectable in newborns to 1233% increase by 2–4 months of age (ANOVA, p = 0.0004). MAG increases significantly again between 2 and 4 months and 1 year of age (79%, p = 0.016). MBP expression was slightly delayed and a significant increase was not apparent until 6 months of age (p = 0.006), and another significant jump between 2 and 4 months and 9 months (192%, p = 0.0112). (C) Immunohistochemistry with anti-MAG antibody revealed that myelination initiates in white matter prior to birth in NMRs as evidenced by positive staining in newborn pups; however MAG immunostaining is not evident in mice until 1 week of age. (d, days; w, weeks; m, months; y, years).