Lab Anim Res.  2017 Sep;33(3):237-243. 10.5625/lar.2017.33.3.237.

Age-dependent differences in myelin basic protein expression in the hippocampus of young, adult and aged gerbils

• Ahn JH
• Lee TK
• Park JH
• Cho JH
• Kim IH
• Lee JC
• Hong S
• Jeon YH
• Kang IJ
• Lee YJ
• Won MH
• Lee CH

• KMID: 2391097
• DOI: http://doi.org/10.5625/lar.2017.33.3.237

Abstract

Myelin degeneration is one of the characteristics of aging and degenerative diseases. This study investigated age-related alterations in expression of myelin basic protein (MBP) in the hippocampal subregions (dentate gyrus, CA2/3 and CA1 areas) of gerbils of various ages; young (1 month), adult (6 months) and aged (24 months), using western blot and immunohistochemistry. Western blot results showed tendencies of age-related reductions of MBP levels. MBP immunoreactivity was significantly decreased with age in synaptic sites of trisynaptic loops, perforant paths, mossy fibers, and Schaffer collaterals. In particular, MBP immunoreactive fibers in the dentate molecular cell layer (perforant path) was significantly reduced in adult and aged subjects. In addition, MBP immunoreactive mossy fibers in the dentate polymorphic layer and in the CA3 striatum radiatum was significantly decreased in the aged group. Furthermore, we observed similar age-related alterations in the CA1 stratum radiatum (Schaffer collaterals). However, the density of MBP immunoreactive fibers in the dentate granular cell layer and CA stratum pyramidale was decreased with aging. These findings indicate that expression of MBP is age-dependent and tissue specific according to hippocampal layers.

Keyword

Myelin basic protein; aging; hippocampus; gerbil

MeSH Terms

Adult*
Aging
Blotting, Western
CA1 Region, Hippocampal
Gerbillinae*
Hippocampus*
Humans
Immunohistochemistry
Myelin Basic Protein*
Myelin Sheath*
Perforant Pathway
Myelin Basic Protein

Figure

• 

  Figure 1 NeuN immunohistochemistry in the hippocampus of young (A), adult (B), and aged (C) gerbils. Numbers of NeuN immunoreactive neurons are not significantly different among all the groups. GCL, granular cell layer; MoL, molecular cell layer; PoL, polymorphic cell layer; SL, stratum lucidum; SO, stratum oriens; SP, stratum pyramidale. Scale bars=400 (A-C), 100 (A1-C3) µm. D: The relative number of NeuN immunoreactive neurons in the dentate gyrus, CA2/3, and CA1 region (n=7 per group). The bars indicate the means±SEM.

• 

  Figure 2 Western blot analysis of MBP in the hippocampus of young, adult and aged gerbils. The relative optical density (ROD) as percentage of immunoblot band is presented (n=7 per group; *P<0.05: significantly different from the young group, †P<0.05, significantly different from the adult group). The bars indicate mean±SEM.

• 

  Figure 3 MBP immunohistochemistry in the hippocampus of young (A), adult (B), and aged (C) gerbils. In the dentate gyrus, the density of MBP immunoreactive fibers is decreased in all layers with age. In the CA2/3 and CA1 regions, the density of MBP immunoreactive fibers is significantly reduced only in the stratum radiatum (SR) with age. GCL, granular cell layer; MoL, molecular cell layer; PoL polymorphic layer; SL, stratum lucidum; SO, stratum oriens; SP, stratum pyramidale. Scale bars=400 (A-C), 50 (A1-C3) µm. D: The relative optical density (ROD) of MBP immunoreactive fibers in the hippocampal subregions (n=7 per group; *P<0.05, significantly different from the young group, †P<0.05, significantly different from the adult group). The bars indicate the means±SEM.

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