Effects Of Early Rehabilitative Training On Brain Structure And Learning Function Following Hypoxic-Ischemic Insult In Neonatal Rats

Part one Establishment the model of Perinatal hypoxia ischemia brain damage in neonatal ratsAbstract: To establish the model of perinatal hypoxia ischemia brain damage in neonatal rats.Method: Thirty-two SD rats were divided into 2 groups randomly: control group,HIBD group. After anesthetized, rats'left common carotid arteries of HIBD groups were ligated. Then they were setted into the hypoxia case where were given 8% nitrogen-oxygen mixture continually. Rats'left common carotid artery of control groups were liberation only. After 72 hours after HIBD, the neurons necrosis in the areas of hippocampus and cortexes were observed by HE staining. Water maze test was used for evaluating the learning-memory ability in P30.Result: Compared with the control group, the brain volume of HIBD group was increasing remarkably. The dead neurons in the areas of hippocampus and cortexes also increased in HIBD group. Many neurons were disappeared in some server areas. Compared with the control group, the learning ability of HIBD group is significantly decreased in the water maze. Conclusion: The model of Perinatal hypoxia ischemia brain damage in neonatal rats were established according to the protocol.Part two Effects of early rehabilitative training on brain structure and learning function following hypoxic-ischemic insult in neonatal ratsAbstract: To explore the effects of early rehabilitative training tasks on brain structure and learning function of neonatal rats with hypoxic-ischemic brain damage.METHODS:Twenty-four SD rats were divided into 3 groups randomly: control group,HIBD group and HIBD training groups. HIBD models were made by Rice method. 72h after HIBD, HIBD plus training group underwent rehabilitative exercises for 30d. Morris water maze tests were used to evaluate rats'learning and memory ability. HE staining was employed to estimate neuron necrosis in hippocampus and cortex areas, and brain weights of three groups were also weighed. The SYN and BDNF expression was detected immunohistochemically in all rats.RESULTS:⑴Compared with training group, the learning ability of HIBD group was significantly decreased, whereas no difference was observed between HIBD-training and control groups. (2) Compared with control group [(0.638±0.019) g], the left half brain weight of both HIBD-training group [(0.428±0.085) g] and HIBD group [(0.348±0.043) g] decreased significantly and the HIBD group decreased more seriously. There were no differences in the right half normal brain weight among the 3 groups. (3) Compared with control group, the number of neuron in both HIBD-training and HIBD groups were significantly decreased, and more obviously in HIBD group. (4) The number of TUNEL positive neurons in the hippocampal CA1 and frontal lobe cortex of the HIBD group and HIBD-training group was more than that of the control group. The number of TUNEL positive neurons in the hippocampal CA1 and frontal lobe cortex of the HIBD-training group was less than that of the HIBD group. (5) The IOD of immunoreactive products of the hippocampal CA1 SYN were significantly decreased in HIBD group as compared with control group and HIBD-training group. There were no marked difference of IOD of SYN between HIBD-training group and control group. (6) The IOD of immunoreactive products of the hippocampal CA1 and frontal lobe cortex BDNF were significantly decreased in HIBD group as compared with control group and HIBD-training group. There were no marked difference of IOD of the hippocampal CA1 and frontal lobe cortex BDNF between HIBD-training group and control group.CONCLUSION: Early rehabilitation training following hypoxic-ischemic insult in neonatal rats can promote the survival of neurons, accelerate the recovery from brain injury and improve the brain learning function.