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

Obiective: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), 15 rats in each group. Another 15 rats in assigned to sham-operation group were subject to no MCAO and no training, All the five groups were randomly divided into three subgroups of the 3rd ,7th and 14th d, 5 rats in each group. Neurological function was evaluated by Zausinger scores. Expressions of Sema 3a and NRP-1 were detected 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(P0.05). The improvement of neurological function in all training groups, was significantly better than those in controls at the 3rd , 7th and 14th d after swimming training(P0.05), especially in training group 3. Zausinger scores at the 3rd d, 7th d and 14th d 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-1-mRNA in all training groups were lower than those in controls at the 3 rd , 7 th and 14 th d after swimming training (P0.05), and the decrease of expressions of Sema 3a-mRNA and NRP-1-mRNA in training group 3 was significantly more obviously compared with other training groups(P0.05). At the 3rd, 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-1-mRNA and GADPH were(0.64±0.13)(,0.53±0.08)and(0.38±0.10)respectively. Conclusion:Exercise training can decrease the expressions of Sema 3a-mRNA and NRP-1-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.