强化训练对局灶性脑缺血大鼠信号素3a及其受体神经纤毛蛋白-1 mRNA表达的影响

Effects of intensive training on expressions of semaphorin 3a and its receptor neuropilin-1 in rats after focal cerebral ischemia

目的:观察不同强度的游泳训练对局灶性脑缺血大鼠Sema3a及其受体神经纤毛蛋白(NRP-1)mRNA表达的影响;探讨强化游泳训练对局灶性脑缺血大鼠的神经保护机制。方法:采用线栓法建立左侧大脑中动脉阻塞2h再灌注动物模型。60只造模成功的雄性SD大鼠随机分为训练1组、训练2组、训练3组和对照组,每组15只。训练1组大鼠每天游泳1次,每次5min;训练2组大鼠每天游泳1次,每次10min;训练3组大鼠每天游泳2次,每次10min;对照组大鼠不做任何训练。另取15只大鼠为假手术组,不阻塞大脑中动脉血流,不做任何训练。以上5组大鼠又随机分为术后3d、7d、14d3个时相点,每个时相点5只大鼠。采用Za-usinger评分法评价神经功能缺损情况。应用RT-PCR测定缺血侧大脑皮质Sema3a和NRP-1的mRNA表达量。结果:假手术组神经功能正常。对照组各时相点的神经功能评分与假手术组同时相点相比,差异均有显著性意义(P<0.05);各训练组训练3d、7d、14d后的神经功能改善情况优于同时相点对照组(P<0.05),训练3组受损神经功能改善最明显,其训练3、7、14d后Zausinger神经功能评分分别为(2.40±0.55)、(3.40±0.55)和(4.20±0.84)。训练1、2、3组各时相点Sema3a和NRP-1的mRNA表达量明显低于对照组同时相点(P<0.05),且训练3组Sema3a和NRP-1的mRNA表达量降低较其他各训练组更明显,其训练3、7、14d后,Sema3a与GAPDH的mRNA表达水平之比分别为(0.62±0.06)、(0.53±0.10)和(0.42±0.06),NRP-1与GAPDH的mRNA表达水平之比分别为(0.64±0.13)、(0.53±0.08)和(0.38±0.10)。结论:运动训练可以减少脑缺血再灌注大鼠Sema3a和NRP-1的mRNA表达量,从而恢复受损神经功能;强化运动训练能够取得更好的效果。

Objective：To observe the effects of swimming training at different intensities on the mRNA expressions of semaphorin 3a and its receptor neuropilin-1 in rats after focal cerebral ischemia, and to explore the possible neuroprotectional mechanism of intensive-swimming training in rats after focal cerebral ischemia. Method：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 2h and before reperfusion. Sixty male model SD 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）, 15rats in each group. Another 15 rats in assigned to sham-operation group were subject to no MCAO and no train ing, All the five groups were randomly divided into three subgroups of the 3,7 and 14 d, 5 rats in each group. Neurological function was evaluated by Zausinger scores. Expressions of Sema 3a and NRP-1 were detect- ed by RT-PCR. Result：The neurological function in sham-operation groups was normal. The differences of Zausinger scores at the same time points between sham-operation group and control group were statistically significant（P〈 0.05）. The im- provement of neurological function in all training groups, was significantly better than those in controls at the 3thd, 7 and 14th d after swimming training（P〈 0.05）, especially in training group 3. Zausinger scores at the 3thd, 7thd and 14thd after swimming training were （2.40± 0.55）, （3.40 ± 0.55） and （4.20 ±0.84） respectively.The levels of expressions of Sema 3a-mRNA and NRP-I-mRNA in all training groups were lower than those in controls at the 3th, 7th and 14th d after swimming training （P〈0.05）, and the decrease of expressions of Sema 3a-mRNA and NRP-I-mRNA in training group 3 was significantly more obviously compared with other training groups（P〈 0.05）. At the 3th, 7th and 14th d after swimming training, the rates of expressions of Sema 3a-mRNA and reduced glyceraldehyde-phosphate dehydrogenase（GAPDH） were （0.62 ±0.06）, （0.53 ± 0.10） and （0.42 ± 0.06） respectively, the rates of expressions of NRP-I-mRNA and GADPH were （0.64 ± 0.13）,（0.53 ±0.08） and （0.38 ±0.10） respective- ly. Conclusion：Exercise training can decrease the expressions of Sema 3a-mRNA and NRP-I-mRNA in rats after cerebral ischemla-reperfusion. Hence, it can improve the injured neurological function and promoted the recovery of sensory function and motor function,and the more intensive the training was, the better the effects were. Author＇s address Department of Rehabilitation Medicine, The Affiliated Hospital of Qingdao University Medical College, Qingdao,266005