Comparison of Adult Hippocampal Neurogenesis and Susceptibility to Treadmill Exercise in Nine Mouse Strains

The genetic background of mice has various influences on the efficacy of physical exercise, as well as adult neurogenesis in the hippocampus. In this study, we investigated the basal level of hippocampal neurogenesis, as well as the effects of treadmill exercise on adult hippocampal neurogenesis in 9 mouse strains: 8 very commonly used laboratory inbred mouse strains (C57BL/6, BALB/c, A/J, C3H/HeJ, DBA/1, DBA/2, 129/SvJ, and FVB) and 1 outbred mouse strain (ICR). All 9 strains showed diverse basal levels of cell proliferation, neuroblast differentiation, and integration into granule cells in the sedentary group. C57BL/6 mice showed the highest levels of cell proliferation, neuroblast differentiation, and integration into granule cells at basal levels, and the DBA/2 mice showed the lowest levels. The efficacy of integration into granule cells was maximal in ICR mice. Treadmill exercise increased adult hippocampal neurogenesis in all 9 mouse strains. These results suggest that the genetic background of mice affects hippocampal neurogenesis and C57BL/6 mice are the most useful strain to assess basal levels of cell proliferation and neuroblast differentiation, but not maturation into granule cells. In addition, the DBA/2 strain is not suitable for studying hippocampal neurogenesis.