Effects of intensive training on the expressions of semaphorin 3A and neuropilin-1 after cerebral ischemia-reperfusion in rats

Objective To observe the effects of intensive training at different intensities on the expressions of semaphorin 3A ( Sema 3A) and its receptor neuropilin ( NP-1 ) and the cell apoptosis in cerebrum after cerebral ischemia-reperfusion in rats,and to investigate the possible mechanism of intensive training in recovery of motor function after cerebral ischemia-reperfusion in rats. Methods To establish animal model of cerebral ischemia-reperfusion in rats,the intraluminal thread method was applied to cause left middle cerebral artery occlusion (MCAO) for 2 h and before reperfusion.After cerebral ischemia-reperfusion model were established for 24 h,60 male model Wistar rats were randomly divided into training group 1 ( swimming for 5 min once a day),training group 2 ( swimming for 10 min once a day),training group 3 (swimming for 10 min twice a day) and control group (no training) ; another 15 rats assigned to the sham-operation group were subject to no MCAO and no training.Neurological function was evaluated by Garcia scores,and terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) was performed to dectect the cortical cell apoptosis.Expressions of neural growth inhibition factor Sema 3A and its receptor NP-1 were detected by immunohistochemistry. Results The neurological function in sham-operation group was normal.The differences of Garcia scores at different time points beween sham-operation group and control group were significant (P ＜ 0.01 ).Garcia scores in all training groups,were significantly higher than those in controls at the 7th and 14th d after swimming training ( P ＜ 0.01 ),especially in training group 3 the Garcia scores were ( 12.80 ± 0.45 ),( 15.20 ± 0.45 ),( 16.80 ± 0.45 ),respectively,at the 3rd,7th and 14th d after swimming training.The rates of positive cell of Sema 3A,NP-1 and TUNEL indexes in all training groups were lower than those in controls at the 3rd,7th and 14th d after swimming training (P ＜ 0.01 ),especially in the training group 3.At the 3rd,7th and 14th d after swimming training in training group 3,the rates of TUNEL indexes positive apoptosis cells were ( 29.43 ± 1.38 ) ％,( 22.30 ± 1.21 ) ％,( 17.58 ± 1.70) ％,respectively,the positive cell rates of Sema 3A were ( 19.64 ± 1.17) ％,(9.73 ± 3.83)％,(8.24 ± 0.87)％,respectively,the positive cell rates of NP-1 were ( 33.95 ± 6.86) ％,( 27.95 ± 1.29 ) ％,( 18.90 ± 1.44 ) ％,respectively,the reduction of positive cells expressions in training group 3 was significantly more obvious compared with other training groups (P ＜ 0.01 or 0.05). Conclusions Rehabilitation training can reduce the expression of positive cell of Sema 3A,NP-1 and TUNEL indexes in rats after cerebral ischemia-reperfusion and can improve motor function recovery and facilitate neural plasticity.The more intensive the training,the better the effects. Key words: Cerebral ischemia-reperfusion ;  Intensive training ;  Senaphorin 3 A ;  Neuropilin-1 ;  Cell apoptosis