Effects Of Treadmill Exercise On Motor Function And Brain Mitochondria Of Rats With Traumatic Brain Injury

Background: Traumatic brain injury(TBI)is a worldwide public health problem;many patients are left different degrees of nerve dysfunction and dyskinesia after traumatic brain injury.There is not an effective method or drug to cure this kind of disease at present,and rehabilitation therapy is still one of the most useful means.Most patients with traumatic brain injury are left severe dyskinesia,cognitive disorder and other dysfunctions,which seriously affect their daily life and self-care ability.Plenty of studies have shown that exercise rehabilitation therapy for patients with traumatic brain injury can improve this disease’s prognosis and improve the motor function of the patients;however,its mechanism has not been clarified completely.This study tries to research the effects of treadmill exercise on motor function and brain mitochondria of rats with traumatic brain injury.Methods: Firstly,we observed the effects of exercises on motor ability of rats with traumatic brain injury.96 adult SD rats were randomly divided into control group,trauma group and treadmill exercise group.Then we developed an international common-used rat model of traumatic brain injury: controlled cortical injury(CCI).The two-week treadmill exercise began 1 day after the operation,and a series of behaviors(including the rat nerve function injury score,foot fault test,etc.)were observed;on the 3rd day after the development of the traumatic brain injury model,Evans blue(EB)staining was used to observe the permeability of blood-brain barrier in rats,and the water content of rats’ brains were detected by dry-wet method;transmission electron microscopy was used to observe mitochondrial morphology in every group;each group of rats’ brains were stained by 2,3,5,three chloride triphenyltetrazolium chloride(TTC)staining to detect their brain volume loss;western blot was used to detect related protein expression of the injured cerebral cortex(HIF-1,Bcl-2,Bax,LC3 B,mfn1,Mfn2).Results: Treadmill exercise group’s weight has always been greater than trauma group and significant differences exist between these two groups on the seventh day after model development(P<0.05);neurological severity score of rats in treadmill exercise group and that of rats in trauma group had statistical difference on the seventh day,tenth day and fourteenth day after model development(P<0.05),and the differences were significant on the seventh day and the tenth day after model development(P<0.01);as for the foot fault test,there was significant difference(P<0.05)between the treadmill exercise group and the trauma group on the seventh and tenth days,and the step pace of treadmill exercise group was higher than that of trauma group,on the fourteenth day after model development,the step pace of treadmill exercise group was obviously higher than that of trauma group,there were significant statistical differences between these two groups(P<0.01);14 days after model development,compared with the treadmill exercise group,the trauma group’s brain defect area was larger and the lesion volume was bigger,and there existed significant statistical difference(P<0.05);brain water content of rats in trauma group was much higher than the other two groups;Evans blue in the brains of trauma group was higher than the other two groups,and compared with the treadmill exercise group,there was statistical difference(P<0.05)between the trauma group and the treadmill exercise group;Compared with trauma group,the situation of brain mitochondria edema of the treadmill exercise group is much better.Western Blot results showed that,compared with trauma group,treadmill exercise group’s HIF-1 expression was down-regulated,Bcl-2 expression was up-regulated,Bax expression was down-regulated and LC3 B,mfn1,Mfn2 expression was up-regulated.Conclusions:Treadmill exercises can promote the body function rehabilitation of rats with traumatic brain injury to some extent and improve their motor function;Treadmill exercises improve brain edema for rats with severe TBI,and protect blood-brain barrier(BBB);Treadmill exercises can improve the necrosis of brain parenchyma and improve the brain function;Treadmill exercises can promote the rats’ brain mitochondrial fusion of and improve the situation of brain mitochondria edema and promote the repairment of brain neurons.