Effect of High Intensity Exercise Preconditioning on the Prevention of Myelin damage in Hippocampus of Male C57BL/6 Mice

Multiple sclerosis (MS) is a common neurodegenerative disease leading to the movement disorder and destruction of myelin. Physical exercise delays the onset of neurodegenerative processes by preventing the destruction of myelin and oligodendrocytes. Therefore, the purpose of this study was to investigate the effect of high-intensity exercise preconditioning on gene expression associated with mylein synthesis and a nerve growth factor-induced gene (NGF) in hippocampus of an animal model of demyelination induced by cuprizone (CPZ).
 
Materials & In total, 40 male C57BL/6 mice were randomly assigned into 4 groups, namely control (C), cuprizone induced demyelination (CPZ), high-intensity interval training (HIIT), and interval training plus CPZ (ITCPZ). The training program was performed on treadmills for 4 weeks, followed by MS induction with 0.2% cuprizone feeding. Meanwhile, the training program continued for 5 weeks with MS induction. The incidence of MS was confirmed by open field test. A real time-PCR was utilzied for the measurment of NGF gene expression, myline basci protein (MBP), and mylein proteolipid protein (PLP). The hippocampus was also stained with hematoxylin-eosin to measure the number of oligodendrocytes.
 
The results showed that the CPZ group had poorer motor activity, lower expression of NGF, lower levels of MBP, and PLP, and fewer oligodendrocytes in hippocampus than those in control group (P<0.05). In addition, the mRNA levels of NGF, MBP, and PLP as well as the number of oligodendrocyte cells increased in ITCPZ group, compared to the CPZ group (P<0.05). Moreover, cuprizone prevented the abnormal motor activity.
 
Discussion & According to the results, high-intensity exercise preconditioning could enhance the remyelination process in hippocampus. Moreover, it improved neuroprotective effect against MS by increasing the expression of NGF gene in hippocampus.