Physical exercise ameliorates memory impairment in offspring of old mice

Abstract

For humans, maternal old age means the age of 35 or older at the time of childbirth. Maternal metabolism not only affects the cognitive function of the offspring, but also affects their physical and neurological development. This study aims to elucidate the effects of exercise training on spatial learning memory, neurogenesis, and apoptosis in the off-spring of old mice. Using mice, the offspring of old mothers showed impaired spatial learning memory, decreased brain-derived neurotrophic factor and postsynaptic density protein 95 levels, suppressed neurogenesis, and increased hippocampal apoptotic cell death. In contrast, the offspring of the old mothers had improved spatial learning memory, increased brain-derived neurotrophic factor and postsynaptic density protein 95 levels, increased neurogenesis, and decreased hippocampal apoptotic cell death when they received exercise training. The present results indicate that there is apparent spatial learning memory impairment among the offspring of old mothers, but by contrast, exercise can ameliorate spatial learning memory impairment. Exercise can be an effective countermeasure against memory decline in the offspring of old mothers.

Keywords: Brain-derived neurotrophic factor; Exercise; Postsynaptic density protein 95; Spatial learning memory.

Fig. 1

Effect of exercise on spatial learning memory of the offspring of old mothers. Upper panel: swimming path of Morris water maze task. Lower left panel: escape latency of Morris water maze task. Lower right panel: time in probe quadrant of Morris water maze task. A, offspring of young mothers (control) group; B, offspring of young mothers with exercise group; C, offspring of old mothers group; D, offspring of old mothers with exercise group. Data are expressed as means±standard error of the mean. *P<0.05 compared to the control group. ^#P<0.05 compared to the offspring of old mothers group.

Fig. 2

Effect of exercise on brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD-95) levels of the offspring of old mothers. Upper panel: representative expressions of BDNF and PSD-95. Lower left panel: relative BDNF expression. Lower right panel: relative PSD-95 expression. A, offspring of young mothers (control) group; B, offspring of young mothers with exercise group; C, offspring of old mothers group; D, offspring of old mothers with exercise group. Data are expressed as means±standard error of the mean. *P<0.05 compared to the control group. ^#P<0.05 compared to the offspring of old mothers group.

Fig. 3

Effect of exercise on Bcl-2 related X protein (Bax) and B-cell lymphoma 2 (Bcl-2) expressions in the hippocampus of the offspring of old mothers. Upper panel: representative expressions of Bax and Bcl-2. Lower left panel: relative Bax expression. Lower right panel: relative Bcl-2 expression. A, offspring of young mothers (control) group; B, offspring of young mothers with exercise group; C, offspring of old mothers group; D, offspring of old mothers with exercise group. Data are expressed as means±standard error of the mean. *P<0.05 compared to the control group. ^#P<0.05 compared to the offspring of old mothers group.

Fig. 4

Effect of exercise on cell death in the hippocampal dentate gyrus of the offspring of old mothers. Upper panel: photomicrographs of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells. The scale bar represents 50 μm. Lower panel: number of TUNEL-positive cells. A, offspring of young mothers (control) group; B, offspring of young mothers with exercise group; C, offspring of old mothers group; D, offspring of old mothers with exercise group. Data are expressed as means±standard error of the mean. *P<0.05 compared to the control group. ^#P<0.05 compared to the offspring of old mothers group.

Fig. 5

Effect of exercise on neurogenesis in the hippocampal dentate gyrus of the offspring of old mothers. Left panel: photomicrographs of neuronal nuclei (NeuN)/5-bromo-2′-deoxyuridine (BrdU)-positive cells. The scale bar represents 50 μm. Right panel: number of BrdU-positive cells. A, offspring of young mothers (control) group; B, offspring of young mothers with exercise group; C, offspring of old mothers group; D, offspring of old mothers with exercise group. Data are expressed as means±standard error of the mean. *P<0.05 compared to the control group. ^#P<0.05 compared to the offspring of old mothers group.