[doi: 10.5505/2017ichc.PP-197]
The Ultrastructural And Molecular Changes In Motor Cortex And Spinal Cord Ventral Horn Motor Neurons Of Rats Exposed To Chronic High Intensity-Intermittent Running Exercise
Zelal Keleş1, Güleser Göktaş2, Deniz Erbaş1, Haydar Ali Demirel3, Saadet Özen Akarca Dizakar4, Çiğdem Elmas42Department of Histology and Embryology, Başkent University, Ankara, Turkey
3Department of Exercise and Sport Physiology, Hacettepe University, Ankara, Turkey
4Department of Histology and Embryology, Gazi University, Ankara, Turkey
OBJECTIVE:
Scientific data on the type of ultrastructural and molecular responses at motor neuron level brought about by long term high intensity exercise or intensive physical activity is scarce. The aim of this study was to evaluate the ultrastructural morphological and molecular changes in the motor neurons at the motor cortex and in ventral horn motor neurons at the cervical and lumbar spinal cord in rats following chronic high intensity-intermittent running exercise.
MATERIAL-METHODS:
30 Wistar albino male rats were distributed into three groups: A: a sedentary control group, B: a group which received moderate intensity-continuous exercise (MICE) 5 days/ week for 13-15 weeks and C: a group which received high intensity-intermittent exercise (HIIE) 5 days/ week for 13-15 weeks. At the end of the observational and experimental period of 13-15 weeks, all the animals were sacrificed and spinal cord was removed. Early apoptotic markers cytochrome c and Bcl-2 were evaluated by immunohistochemical method for investigating mitochondrial dysfunction in motor neurons and glial cells. Ultrastructural morphologic evaluations were carried out by electrone microscope.
RESULTS:
Unlike other groups a tendency of reduction in antiapoptotic Bcl-2 immunoreactivity and a tendency of rise of proapoptotic cytochrome c immunoreactivity were observed at all three anatomic levels in the HIIE group, but these changes were not pronounced. Sporadic apoptotic cell changes were observed by electron microscopic evaluation in the HIIE group.
CONCLUSION:
Although chronic high intensity-intermittent running exercise did not lead to a pathologic apoptotic process or to degeneration in rat motor neurons the non-significant changes in cytochrome c and Bcl-2 immunoreactivities can be considered as a mitochondrial dysfunction trend failing to activate caspases.
Figure 1
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Bcl-2 immunostaining in motor cortex of the control (A), moderate intensity-continuous exercise (B), high intensity –intermittent exercise (C) groups and cytochrome c immunostaining of the control (D), moderate intensity-continuous exercise (E), high intensity –intermittent exercise (F) Neurons () and glial cells (). (immunoperoxidase-Hematoxylin magnification 400x)
Figure 2
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Motor cortex, of control group (A,B,C), moderate intensity-continuous exercise group (D,E,F) and high intensity –intermittent exercise group (G,H,I); neuron (), glial cells (), vessel (), Nissl body(), edema(), nucleus (), nucleolus (), granular endoplasmic reticulum() and mitochondrion (). Toluidine blue-stained semi-thin cross sections and Uranyl acetate and lead citrate stained thin section (C, F, I).
Figure 3
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Bcl-2 immunostaining in spinal cord cervical region of the control (A), moderate intensity-continuous exercise (B), high intensity –intermittent exercise (C) groups and cytochrome c immunostaining of the control (D), moderate intensity-continuous exercise (E), high intensity –intermittent exercise (F) Neurons () and glial cells (). (immunoperoxidase-Hematoxylin magnification 400X)
Figure 4
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Bcl-2 immunostaining in spinal cord lumbar region of the control (A), moderate intensity-continuous exercise (B), high intensity –intermittent exercise (C) groups and cytochrome c immunostaining of the control (D), moderate intensity-continuous exercise (E), high intensity –intermittent exercise (F) Neurons () and glial cells (). (immunoperoxidase-Hematoxylin magnification 400X)
Figure 5
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Spinal cord cervical region of control group (A,B,C), moderate intensity-continuous exercise group (D,E,F) and high intensity –intermittent exercise group (G,H,I); neuron (), glial cells (), vessel (), Nissl body(), nucleus (), nucleolus (), granular endoplasmic reticulum() and mitochondrion (). Toluidine blue-stained semi-thin cross sections (A,D,G magnification 400x, B,E,H magnification 100x and Uranyl acetate and lead citrate stained thin section (C, F, I).
Figure 6
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Spinal cord lumbar region of control group (A,B,C), moderate intensity-continuous exercise group (D,E,F) and high intensity –intermittent exercise group (G,H,I); neuron (), glial cells (), vessel (), Nissl body(), nucleus (), nucleolus (), granular endoplasmic reticulum() and mitochondrion (). Toluidine blue-stained semi-thin cross sections (A,D,G magnification 400x, B,E,H magnification 1000x and Uranyl acetate and lead citrate stained thin section (C, F, I).