Effects of treadmill exercise on activity, short-term memory, vascular dysfunction in maternal separation rats

Abstract

Maternal separation during early life causes psychiatric and neurologi-cal disorders such as anxiety and depression. Depression or anxiety is closely associated with memory impairment. The purpose of this study was to investigate the effect of treadmill exercise on activity, short-term memory, vascular dysfunction using maternal separation-induced de-pression model. Maternal separation started on 15-day-old rats. The rats in the maternal separation and fluoxetine injection group received intraperitoneal injection of 5 mg/kg of fluoxetine one time daily for 15 days from 21 to 35 days. The rats performed treadmill exercise once a day during 15 days from 21 to 35 days. There was low activity and short-term memory was decreased in the maternal separation rats. Treadmill exercise and fluoxetine injection increased activity and ameliorated memory impairment. The number of rat endothelial cells antigen-1 (RECA-1) of microvessels was decreased in the maternal separation rats. The number of RECA-1was increased by treadmill exercise and fluoxetine injection. Expression of matrix metalloproteinase-9 (MMP-9) was increased and expressions of zonula occludens-2 (ZO-2) and oc-cludin were decreased in the maternal separation rats. Treadmill exer-cise and fluoxetine injection suppressed MMP-9 expression and en-hanced ZO-2 and occludin expressions in the maternal separation rats. The present study shows treadmill exercise and antidepressant treat-ment ameliorates depressive symptom and short-term memory impair-ment by protecting from blood-brain barrier damage.