| Objectives The study was designed to investigate T3 in neonatal rats excitotoxicity brain injury the impact of behavior in neonatal mice excitotoxic brain damage by neurobehavioral function research,and explore a new drug treatment preterm infant white matte damage and provide a theoretical basis.Methods 71 five-days old ICR-type neonatal mice coming form different dams were selected and randomly divided into three groups randomly:control,model and the treatment group,of which the treatment group was divided into low-dose group (2μg/kg),middle-dose group(5μg/kg)and high-dose group(10μg/kg)All mice received intracerebral injection at post-natal day 5.The control group was injected with PBS,while the model and treating groups were injected with ibotenate.All pups were done intraperitoneal injections at 1,24,48,72 and 96 hours.The control and model groups received PBS,while the treating groups received T3.Behavior changes of all mice were observed with single blind method including surface righting reflex (P10),swimming development(P10,P12),open field behavior(P30,P31,P32)and Ymaze discrimination learning experiment(P33,P34).All mice were sacrificied, dislodged for consecutive sections and calculating the diameter of the brain damage and hippocampus.Comparison between the experimental results of group differences.Results 1.Surface righting reflex There were no difference between all groups(P＞0.05).2.Swimming test Swimming scores of the model group(6.0±1.0) were decreased significantly compared with the control group(7.5±1.25)(P＜0.0125) at post-natal day 10.At post-natal day 12,swimming scores of the model group(8.00±3.00)were low significantly compared with the control group(9.00±0.00)(P＜0.0125)and the high-dose groups(9.00±0.00)(P＜0.0125).While there were no difference between the model and others groups(P＞0.0125)at post-natal day 10 and 12.Swimming test score in the direction of the model group(2.00±1.00)were decreased significantly compared with the control group(3.00±0.25)(P＜0.0125)at post-natal day 10,while there were no difference between the model and others groups(P＞0.0125)at post-natal day 10 and 12.There were no difference between all groups in Swimming angle at post-natal day 10 and 12(P＞0.0125),At post-natal day 10,there were no difference between all groups usage of limbs in swimming test.,while the model group(1.00±1.00)were decreased significantly compared with the control(2.00±0.00)and the high-dose groups(2.00±0.00)at post-natal day 12(P＜0.0125).3.open field test There were no difference between all groups in latency time at post-natal day 30,31,32(P＞0.05);In crossing and rearing score,the model group(56.29±32.54)were decreased significantly compared with the control group(85.71±44.98)(P＜0.05)at post-natal day 30,high-dose group(69.79±36.21)at post-natal day 31(P＜0.05),middle-dose(55.20±36.43)and high-dose groups(70.92±43.67)at post-natal day 32(P＜0.05);There were no difference between all groups in number of grooming and defecation at post-natal day 30,31,32(P＞0.05).4 Y-Maze The model group(21.28±6.28)were increased significantly compared with the control group(15.00±4.71)and high-dose group(15.79±4.48)in learning times(P＜0.05)at post-natal day 33.The model group(0.793±0.100)were decreased significantly compared with the control(0.907±0.073)and high-dose groups(0.914±0.095)(P＜0.05)in right reaction rate at post-natal day 34(P＜0.05).5.Histologica section of model and treating groups can observed cysts lesion of right cerebral hemisphere white matter and.There were no white matter lesions in saline control group mice brain. Conclusions 1.T3 excited toxicity of brain damage in mice in the early and late stage of development of a facilitating role.2 High-dose(10μg/kg)T3 excited to promote the toxic brain damage in mice swimming test movement of the limbs,and long-term response to learning and memory function;the middle-dose(5μg/kg)T3 enhance long-term reaction alone;there are no improvement in swimming behaviors and long-term reacting and learning and memory function in the low-dose(2μg/kg)T3 group.
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