Treadmill exercise alleviates impairment of spatial learning ability through enhancing cell proliferation in the streptozotocin-induced Alzheimer’s disease rats

Abstract

Alzheimer’s disease is the most common cause of dementia. This disease is a progressive and irreversible brain disorder accompanied with severe learning and memory impairment. Exercise increases cognitive ability, attenuates motor deficits, increases new neuron formation, and ameliorates neurological impairments in several neurodegenerative diseases. This study investigated the effects of treadmill exercise on spatial learning ability in relation with cell proliferation in the hippocampus. The rat model of Alzheimer’s disease was induced by intracerebroventricular (ICV) injection of streptozotocin (STZ) using a stereotaxic instrument. The rats in the exercise groups were forced to run on a treadmill for once 30 min daily for 28 consecutive days starting at 3 days after the ICV injection of STZ. Radial 8-arm maze test was conducted for the spatial learning ability. New neuron formation in the hippocampus was detected by 5-bromo-2’-deoxyuridine (BrdU) immunohistochemistry. Brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) expressions were examined by western blot analysis. The present results show that ICV injection of STZ impaired spatial learning ability. Decreased cell proliferation with decrement of BDNF and TrkB expressions in the hippocampus were observed in the STZ-induced Alzheimer’s disease rats. However, treadmill exercise alleviated deficits of spatial learning ability. Treadmill exercise enhanced cell proliferation and increased BDNF and TrkB expressions in the rats with ICV injection of STZ. The present study suggests that treadmill exercise can be a useful strategy for treating memory impairment induced by several neurodegenerative diseases.

How does environmental enrichment reduce repetitive motor behaviors? Neuronal activation and dendritic morphology in the indirect basal ganglia pathway of a mouse model

“…Exercise improves cognitive and motor task performance (e.g. Leggio et al, 2005; Sim, 2014), and increases expression of neurotrophic factors (e.g. BDNF) (Turner & Lewis, 2003; Berchtold et al, 2010; Sim, 2014), hippocampal neurogenesis (van Praag, 2009; e.g.…”

Comparison of the behavioral effects of exercise and high fat diet on cognitive function in adolescent rats

“…Consistent with our study, the several reports have demonstrated that the sham+Ex group exerted no significant effect on the number of error choice in the radial 8-arm maze test as compared to the sham group. However, treadmill exercise enhanced BDNF and TrkB expressions in the hippocampus of rats (Sim, 2014). Many studies have shown that treadmill exercise in young normal animals exerted no significant effect on spatial learning and memory and short-term memory in the radial 8-arm maze and step-down avoidance tests (Heo et al, 2014; Kim et al, 2010).…”

Treadmill exercise ameliorates symptoms of Alzheimer disease through suppressing microglial activation-induced apoptosis in rats

“…AD was induced according to the previously described method (Jee et al, 2008; Sim, 2014). The rats were anesthetized with Zoletil 50 (10 mg/kg, intraperitoneally; Vibac Laboratories, Carros, France) and placed in a stereotaxic frame.…”

“…Alzheimer disease (AD) gradually impairs learning ability and memory function (Sim, 2014), and the incidence of AD is 50%–80% of dementia cases. The exact pathogenesis of AD is still not known.…”

“…Exercise is known to inhibit apoptosis and improves memory functions (Kim et al, 2014a; Kim et al, 2014b; Sim, 2014). However, the effects of treadmill exercise on AD in relation with microglial activation are not evaluated.…”