Effects of treadmill exercise-intensity on short-term memory in the rats born of the lipopolysaccharide-exposed maternal rats

Abstract

Maternal infection is an important factor causing neonatal brain injury and later developmental disability. In the present study, we investigated the effects of treadmill exercise intensity on short-term memory, hippo-campal neurogenesis, and expression of brain-derived neurotrophic factor (BDNF), and tyrosine kinase receptor B (TrkB) in the rats born of lipopolysaccharide (LPS)-exposed maternal rats. The rats were divided into six groups: control group, mild-intensity exercise group, moderate-intensity exercise group, maternal LPS-exposed group, maternal LPS-exposed and mild-intensity exercise group, maternal LPS-exposed and moderate-intensity exercise group. The rats in the exercise groups were forced to run on a treadmill for 30 min 5 times a week for 4 weeks. The exercise load consisted of running at the speed of 8 m/min for the mild-intensity exercise groups and 14 m/min for moderate-intensity exercise groups. The latency in the step-down avoidance task was determined for the short-term memory. Immunohistochemistry for 5-bro-mo-2'-deoxyuridine was performed to determine hippocampal cell proliferation and neurogenesis. Western blot analysis was performed for the detection of BDNF and TrkB expression. In the present study, treadmill exercise improved short-term memory deteriorated by maternal LPS exposure. Treadmill exercise increased cell proliferation and neurogenesis in the hippocampal dentate gyrus of the rats born of the LPS-exposed maternal rats. Treadmill exercise increased BDNF and TrkB expression in the hippocampus of the rats born of the LPS-exposed maternal rats. These effects of treadmill exercise were similarly appeared at both mild-intensity and moderate-intensity.