High-intensity Interval Training On Neuroplasticity, Brain-derived Neurotrophic In The Hippocampus And Depression Recovery Of Post-stroke Depression Rats

Objective:To observe the effect of high-intensity interval training?HIIT?on the degree of depression,the morphology of neurons in the hippocampus,the expression of mature brain-derived neurotrophic factor?mBDNF?protein and its precursor proBDNF in the post-stroke depression?PSD?rats,and to investigate potential mechanisms of HIIT on PSD.Methods:Wistar rats were randomly assigned into Control,Sham,PSD,moderate intensity continuous training?MICT?,and HIIT groups?n=10?.In the PSD,MICT,and HIIT groups,the left middle cerebral artery occlusion/reperfusion was performed and chronic unpredictable mild stress was given.And only arteries were isolated without occlusion or reperfusion in the Sham group.After PSD model was successful made,the maximum speed?Smax?and the blood lactate threshold corresponding speed(S_LT)were measured.Different intensity training protocols(MICT<S_LT;S_LT<HIIT<Smax)were carried out on the MICT and HIIT groups respectively.The behavioral tests?forced swimming test?FST?,and sucrose preference test?SPT??were performed in the five groups before and 4 weeks after training.Nissl staining was used to observe the changes of neuronal cell morphology in the left hippocampus.The expression of mBDNF,tropomyosin receptor kinase B?TrkB?,proBDNF,pan-neurotrophin receptor 75?p75NTR?,NR2A,NR2B proteins and BDNF mRNA,tissue plasminogen activator?tPA?mRNA in the hippocampus were detected by Western blotting,immunohistochemistry or RT-PCR after training.Results:Compared with the other groups,the S_LTT decreased,and the blood lactate concentration increased in the PSD group.Longer immobility time?F=70.24,P<0.01?during the FST and lower sucrose preference?F=28.34,P<0.01?during the SPT were observed in the PSD group.The expression of mBDNF,TrkB,NR2A protein and BDNF mRNA,tPA mRNA decreased,while the expression of proBDNF,p75NTR and NR2B protein increased in the PSD group.The difference was statistically significant?P<0.05?.Immunohistochemistry showed that the expression of mBDNF was decreased in hippocampus and the expression of proBDNF was increased in PSD group?P<0.05?.Neuronal cells in the hippocampus were loosely arranged;cells were missing.Nissl body was lightly stained,and even dissolved in the PSD group.After 4 weeks of training,immobility time during the FST increased?MICT:q=10.82,P<0.01;HIIT:q=21.82,P<0.01?and sucrose preference during the SPT decreased?MICT:q=6.68,P<0.01;HIIT:q=14.32,P<0.01?in the MICT and HIIT groups;the expression of mBDNF,TrkB,NR2A protein and BDNF mRNA,tPA mRNA increased;the expression of proBDNF,p75NTR and NR2B protein decreased.Immunohistochemistry showed increased expression of mBDNF in hippocampus and decreased expression of proBDNF in CA3and DG?P<0.05?.Nissl staining in the CA1 and DG areas showed that the neuronal cells were arranged neatly;the layers were dense,and the Nissl body was deeply stained.The change in HIIT group was more significant than that in the MICT group?P<0.05?.There was a negative correlation between mBDNF/proBDNF ratio and the immobility time during the FST?r=-0.65,P<0.01?.A positive correlation was found between mBDNF/proBDNF ratio and sucrose preference during the SPT?r=0.67;P<0.01?.Conclusion:This study demonstrates that the balance between mBDNF and proBDNF in the hippocampus are likely to play an important role in the pathogenesis of PSD.And HIIT was superior to MICT in improving depression and neural plasticity,increasing mBDNF/proBDNF ratio in the hippocampus of the PSD rats.