Figure 3.

Naked mole-rats are born with more mature brains than mice yet maintain neuronal plasticity longer than mice. Naked mole-rat (NMR) and mouse brains were stained with newborn neuron marker doublecortin (DCX) and counterstained with hematoxylin. Immunostaining indicates that NMRs maintain DCX-positive cells in neurogenic (A) dentate gyrus and (B) subventricular as well as (C) cortex longer than mice. (A) Specifically, the newborn NMR dentate gyrus contains clearly defined cell layers with lower DCX-staining than newborn mice indicating greater in utero brain development in NMRs than mice. In both species, DCX-positive dentate gyrus cells become rare by 3 months of age. (B) Immunoreactivity is evident in NMR subventricular through 6 months of age, but becomes rare in 3-month-old mice. (C) Mice display poorly defined cortical organization until 2 weeks of age. In contrast, even at birth, NMRs exhibit a well-developed cortical layer I (yellow double arrow). By 2 weeks of age, mouse cortical DCX immunoreactivity is lost but it persists in NMRs. (B) Scale bar: 100 μm.