Effects of electric stimulation on recovery of motor function and expressions of Nogo-A and Nogo receptor after acute cerebral infarction in rats

Objective To investigate the mechanisms of electric stimulation in improving neuro-rehabilitation by observing the effects of impaired limbs and bilateral electric stimulation on motor function and expressions of Nogo-A and Nogo receptor(NgR) following acute cerebral infarction in experimental rats.Methods Adult male Sprague-Dawley(SD) rats were randomly divided into the normal(8 rats),sham operation,control,impaired limb and bilateral electric stimulation groups(each group had 32 rats).The acute cerebral infarction model was mimicked by using the middle cerebral artery occlusion(MCAO) technique.After cerebral infarction for 24 h,the rats were treated with or without electric stimulation everyday according to different groups,followed by evaluation of the motor function and expression of Nogo-A and NgR in the border zone of cerebral infarction for 3,7,14 and 21 days by using the beam walking test(BWT) and immunohistochemistory. Results Motor function was significantly improved in the treatment groups with electric stimulation compared with the control group(P0.05).Also,the effect of the bilateral electric stimulation on recovery of motor function was better than that of the impaired limb treatment.Further studies demonstrated that the expressions of Nogo-A and NgR were remarkably increased in the control and treatment groups after cerebral infarction for 3 days(P0.05) in contrast to the sham operation group,and were decreased after 7 days and returned to the basal level following 21 days,whereas no significant changes were observed in the normal and sham operation groups at each timepoint.When compared with the control group,the expressions of Nogo-A and NgR in the treatment groups were significantly reduced after cerebral infarction for 3 day,however,no significant differences were found after 21 days,in contrast to the impaired limb electric stimulation group,they were lower in the bilateral treatment group 7 days after cerebral infarction(P0.05) and returned to the same level of the impaired limb treatment group after 14 days.Conclusions Treatment of acute cerebral infarction with electric stimulation,in a particular bilateral stimulation,can improve the movement of the paralyzed extremities and down-regulate the expressions of Nogo-A and NgR.Therefore,improvement of motor function by electric stimulation involves the inhibition of Nogo-A and NgR expressions after acute cerebral infarction.