Objective:To observe the effect of different starting time and intensities of exercise training on neurologic function change and the expression of brain-derived neurotrophic factor(BDNF) and 5-hydroxytryptamine receptor 1A subtyte(5-HT1A) in hippocampus after cerebral infarct in rats

and to discuss the mechanism of exercise training to improve neurological function recovery in cerebral infarction rats. Methods:The study has three parts:1 Adult male Sprague-Dawley(SD) rats were randomly divided into S1

I1

E1

E3 and E5 groups

namely sham group 1

infarct group 1

exercise training of day 1 after infarct group

exercise training of day 3 after infarct group and exercise training of day5 after infarct group respectively(five rats in each group;the intensity of exercise training was 15 m/min). The best starting time of exercise training after cerebral infarct was decided according to modified neurological severity scores(m NSS)and expression of BDNF protein. 2Basing on the best starting time and different intensities of exercise training

rats were randomly divided into S2

I2

L

M and H groups

namely sham group 2

infarct group 2

low-intensity exercise training after infarct group

moderate-intensity exercise training after infarct group and high-intensity exercise training after infarct group(five rats in each group;the intensity of L group

M group and H group was 10 m/min

15 m/min and 20 m/min respectively). The best intensity of exercise training after cerebral infarct was decided according to m NSS and expression of BDNF protein. 3WAY100635

a 5-HT1 A special receptor antagonist

was used to observe the effect of 5-HT1 A on BDNF in the rats of exercise training after cerebral infarct. In this part

rats were randomly divided into S3

I3

E and W groups

namely sham group 3

infarct group 3

exercise training group and WAY100635 group(5 rats in each group). Western blot and fluorogenic quantitative PCR were used to detect the protein and m RNA level of 5-HT1 A and BDNF. Results:1The m NSS was decreased in E1

E3 and E5 group than in I1 group(P<0.01)

without significant statistical differences between E1

E3 and E5 groups. The m NSS was also significantly up-regulated in E3 and E5 group than in I1 group(P<0.05)

without significant statistical differences between E3 and E5 groups. 2The m NSS was decreased in M group than in I2 group(P<0.01)

and the BDNF protein was up-regulated in M group than in I2 group(P<0.01)

without significant statistical differences in L

H and I2 groups. The best intensity of exercise training after cerebral infarct was 15 m/min. 3The m NSS was decreased in E group than in I3 group(P<0.05)

without significant statistical differences between E group and W group. The protein and m RNA level of 5-HT1 A and BDNF was significantly increased in E group than in I3 group(P<0.05)

without significant statistical differences between E group and W group. Conclusion:Exercise training can improve neurological function and up-regulate the expression of 5-HT1 A and BDNF after cerebral infarct. Early exercise training(day 1

day 3 or day 5)is benefit to neurological function recovery and it can up-regulate BDNF effectively day 3 or day 5 after cerebral infarct. Moderate intensity of exercise training can promote neurological function recovery and BDNF expression. The mechanism of exercise training which promote BDNF expression after cerebral infarct may be not related to 5-HT1 A.