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0090-2977/19/5106-00438 © 2019 Springer Science+Business Media LLC
Neurophysiology, Vol. 51, No. 6, November, 2019
Physical Training Moderates Blood-Brain-Barrier
Disruption and Improves Cognitive Dysfunction
Related to Transient Brain Ischemia in Rats
N. Shamsaei,
1
H. Abdi,
2
and F. Moradi
3
Received May 29, 2019
Cerebral ischemia induces structural and functional damage in the brain, which leads to cell death and
cognitive dysfunction. According to the evidences, physical exercise training exerts a neuroprotective
effect and may decrease ischemia-induced injuries in this case. We evaluated the protective effects of
physical training on blood-brain-barrier (BBB) disruption, neuronal death, and cognitive dysfunction
induced by cerebral ischemia in male rats. Thirty-six adult male rats were selected randomly and allocated
into three groups, ischemia (I), ischemia+exercise (I+E), and sham (Sh). Brain ischemia was induced
via occlusion of the common carotid arteries for 20 min. Before occlusion, animals of the I+E group ran
on a treadmill 5 days a week for 4 weeks. Spatial memory performances of rats were evaluated by the
Morris water maze test. Apoptotic cell death in the dentate gyrus (DG) of the hippocampus was detected
by a TUNEL assay, while the level of disruption of the BBB was measured by an Evans blue assay.
Cerebral ischemia caused spatial memory impairment; exercise training improved the index of memory
impairment following ischemia significantly (P < 0.05). Also, exercise training significantly reduced the
BBB permeability in I+E rats compared with the I group (P < 0.05). In addition, the number of TUNEL-
positive cells was significantly greater in I rats, while exercise training significantly reduced apoptotic
cell death (P < 0.05). Our results indicate that physical training exerts noticeable neuroprotective effects
against brain ischemic injury, in particular by preserving the BBB integrity.
Keywords: cerebral ischemia, physical exercise, blood-brain-barrier (BBB), cell death, cognitive
dysfunction.
1
Department of Physical Education and Sport Sciences, Ilam University,
Ilam, Iran.
2
Department of Physical Education and Sport Sciences, Payam-e Noor
University, Tehran, Iran.
3
Department of Physiology, School of Medicine, Zanjan University of
Medical Sciences, Zanjan, Iran.
Correspondence should be addressed to N. Shamsaei
(e-mail: shamsaeinabi@gmail.com), or to H. Abdi
(e-mail: abdi197866@gmail.com), or to F. Moradi
(e-mail: moradifatemeh98@yahoo.com).
INTRODUCTION
Reduction or cessation of blood flow to a part
of the brain due to blockage of a cerebral artery
leads to brain ischemia [1]. Cerebral ischemia is a
standout cause of disability and death in the world,
with over 80% of all cases activated by ischemic
occasions [2]. Cerebral ischemia-reperfusion (IR)
injury causes permanent degeneration in the CNS,
which is a primary cause of death in neurological
diseases [3]. During brain ischemia, cerebral blood
flow, important metabolite levels, and that of oxygen
are reduced; returned blood flow during reperfusion
leads to intense cellular oxygenation and augmented
generation of reactive oxygen species (ROSs).
Then, the respective effects on cell signaling can
lead to dramatic tissue damage [4]. Recent studies
demonstrated that certain pathological features are
related to the IR effects, including the creation
of ROSs, energy failure, neuronal apoptosis, an
inflammatory response, and, finally, to neurological
dysfunction [5].
The hippocampus is vitally important for memory
functions [6, 7]. This cerebral structure is more
sensitive to ischemic insults than other areas of the
brain. Ischemia readily leads to strong physical and
functional damages in the hippocampus [8].
The blood-brain barrier (BBB) is a specialized
endothelial structure in the CNS. The BBB is
composed of specialized cerebral endothelial
cells, which form a tight seal due to the presence
of tight junctions, which restricts the entry of
plasma components and blood cells into the
brain [9]. Several neuropathological conditions,
DOI 10.1007/s11062-020-09840-x