Effect and Mechanism of Qixian Tongluo Formula on Contralateral Corticospinal Tract Remodeling and Motor Functional Recovery in Rats with Cerebral Infarction
Objective To observe the effect of Qixian Tongluo Formula on contralateral corticospinal tract(CST)remodeling and motor functional recovery in rats with cerebral infarction,and to explore its potential molecular mechanism from the perspective of regulating factors related to never remodeling.Methods The rat middle cerebral artery occlusion(MCAO)model was established by silk thread ligation.Fifty model rats were randomly divided into model group,citicoline group(0.054 g·kg-1),Qixian Tongluo Formula low-,medium-and high-dose(7.83,15.66,31.32 g·kg-1)groups,and sham operation group,with 10 rats in each group.The intervention administration was started on the 3rd day after operation once a day for 26 consecutive days.On the 3rd,14th and 28th day after operation,the gross motor function was evaluated by Longa score,and the fine motor function was evaluated by beam-walking test(BWT)score.The contralateral motor cortex was injected with the nerve tracer biotin dextran amine(BDA)on the 14 th day after operation to anterogradely trace the CST.On the 28th day after operation,the expression of axonal growth associated protein-43(GAP-43)and BDA positive fibers in the contralateral motor cortex and cervical spinal cord were detected by immunohistochemistry.The co-localization areas of BDA positive fibers and presynaptic marker protein vesicular glutamate transporter 1(VGLUT1)in the cervical spinal cord gray matter were detected by immunofluorescence.The expressions of brain-derived neurotrophic factor(BDNF),glial cell-derived neurotrophic factor(GDNF),nerve growth factor(NGF)and nerve remodeling-associated inhibitory factor[Nogo-A,oligodendrocyte myelin glycoprotein(OMgp)and myelin-associated glycoprotein(MAG)]in the contralateral motor cortex were detected by Western Blot.Pearson correlation analysis was used to analyze the correlation between Longa score or BWT score and BDA/VGLUT1 co-localization area,respectively.Results Compared with the sham operation group,rats in the model group had obvious symptoms of motor function deficits,and the Longa scores were significantly increased(P＜0.01)and the BWT scores were significantly decreased(P＜0.05,P＜0.01)at each time point.The expression of GAP-43 in the contralateral motor cortex and cervical spinal cord was up-regulated(P＜0.05),the number of edge-crossing fibers from the posterior funiculus in cervical cord was increased(P＜0.05),the co-localization area of BDA/VGLUT1 in the gray matter of the cervical spinal cord was increased(P＜0.05),the expressions of BDNF,GDNF and NGF in the contralateral motor cortex were up-regulated(P＜0.05),while the expressions of Nogo-A,OMgp and MAG were down-regulated(P＜0.05).Compared with the model group,the Longa scores in each administration group on the 14th and 28th day after MCAO operation were significantly decreased(P＜0.01),the BWT scores were significantly increased(P＜0.01),the expression of GAP-43 in the contralateral motor cortex and cervical spinal cord was significantly up-regulated(P＜0.01).The number of edge-crossing fibers from the posterior funiculus in cervical cord was significantly increased(P＜0.01),the co-localization area of BDA/VGLUT1 in the gray matter of the cervical spinal cord was significantly increased(P＜0.01).The expressions of BDNF,GDNF and NGF in the contralateral motor cortex were significantly up-regulated(P＜0.01,P＜0.05),while the expressions of Nogo-A,OMgp and MAG were significantly down-regulated(P＜0.05),and the most significant effect was observed in the high dose group.The Longa score was negatively correlated with the co-localization area of BDA/VGLUT1(r=-0.89,P＜0.01),and the BWT score was positively correlated with the co-localization area of BDA/VGLUT1(r=0.84,P＜0.01).Conclusion Qixian Tongluo Formula can improve motor function through promoting contralateral CST remodeling in MCAO rats after cerebral infarction,and the molecular mechanism may be related to the regulation of the expression of nerve remodeling-associated factor in the contralateral motor cortex.
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