Early physical training improves long-lasting prognosis following hypoxic-ischemic brain damage in neonatal rats / 中华神经医学杂志

ABSTRACT

Objective To investigate the effect of early physical training on long-lasting neurological function,pathology changes,spatial learning and memory abilities,sensorimotor function and ultrastructure changes in neonatal rats with hypoxic-ischemic brain damage (HIBD).Methods Ninety 7-day-old sprague-dawley rats were randomly divided into three groups:a group that was subjected to left carotid ligation followed by 2 hours hypoxic stress (vehicle group),a group that received physical trainings (grabbing,rotation,walking and balance) 1 weeks after HIBD event (trained group) and a sham-operated group that was subjected to a sham-operation without ligation and hypoxic stress (n=30).Following four weeks of physical trainings,neurological scale was performed on all the rats; the number of neurons in the CA1 region of hippocampus and cortex forehead was measured by Nissl count; the expression levels of synaptophysin and c-fos were examined; Morris water maze tests and cortex sensorimotor tests were performed to detect the spatial learning and memory abilities and sensory functions; transmission electron microscope was employed to observe the synapses and neuronal ultrastructure.Results As compared with those in the vehicle group,the neurological scale scores were significantly increased in the trained group and the sham-operated group 14,21 and 28 days after trainings (P＜0.05).As compared with those in the vehicle group,the number of neurons in the left hippocampal CA1 area and cortex increased in the trained group and sham-operated group (P＜0.05).The expressions of synaptophysin and c-los in the trained group increased significantly as compared with those in the vehicle group (P＜0.05).As compared with those in the vehicle group,the spatial learning and memory abilities and sensorimotor functions in the trained group were significantly increased (P＜0.05).The ultrastructure of the left hippocampus and cortex was remarkably abnormal in the vehicle group by the transmission electron microscopy,while no obvious abnormality was observed in the trained group.Conclusion Early physical training can restrain neuron damage in the hippocampus and cortex and enhance synaptic plasticity to ameliorate the long-term neurological function after HIBD; the strong expression of synaptophysin and c-fos in the hippocampus and cortex caused by early physical training may be one of the improvement mechanisms.