ABSTRACT
Objective To observe the influence of swimming training on the expression of nerve growth factor (NGF) and neurotrophins-3 (NT-3) in rats with cerebral infarction,and to explore the underlying neuroprotection mechanism of exercise training on cerebral infarction.Methods Forty-five healthy male Sprague-Dawley rats were randomly divided into a sham-operation group,a control group and a training group,with 15 rats in each group.Each group was further divided into a 3-day,7-day and 14-day subgroups,which amounts to 9 groups.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 before reperfusion.The rats of the training group were given swimming training for 10 min,once daily,while those of the sham-operation and control groups were not given any training.Neurological deficits were assessed using Bederson scores.The expression of NGF mRNA and NT-3 mRNA in the ischemiareperfusion pallium was examined using reverse transcription-polymerase chain reaction (RT-PCR).Results The rats of the sham-operation group showed no neurological deficits.At the same time points,the average Bederson scores of the training group were significantly lower than the control group,but significantly higher than the sham group.Moreover,the 14 d training group had the lowest Bederson score (1.20 ±0.45),compared to the value 3 and 7 days after modeling.The expression of NGF mRNA and NT-3 mRNA of ischemic cerebral cortex in the training group was significantly improved when compared to the sham-operation group or the control group.On day 14,the expression of the NGF mRNA (0.66 ± 0.07),and the NT-3 mRNA (0.79 ± 0.06),were significantly higher than those on day 3 and 7.Conclusions Swimming training could increase the expressions of NGF mRNA and NT-3 mRNA in the ischemic cerebral cortex.It might be one of the key mechanisms that exercise training could promote the recovery of damaged neurological function in rats with cerebral infarction.