新生鼠缺氧缺血性脑损伤海马、皮层MAG表达变化研究

Variation of expression of myelin-associated glycoprotein at hippocampal dentate gyrus and cortex in hypoxic ischemic brain damaged newborn rats

【目的】探讨新生鼠缺氧缺血性脑损伤(hypoxic ischemic brain damage,HIBD)海马齿状回、皮层髓鞘相关糖蛋白(myelin associated glycoprotein,MAG)表达的变化及其意义。【方法】7日龄SD大鼠64只,随机分为假手术组(n=32)、HIBD组(n=32);HIBD组参照Rice法制作HIBD新生大鼠模型,两组动物分别于缺氧缺血(hypoxic ische-mic,HI)后24 h4、8 h、72 h、7 d四个时间点断头取脑制作免疫组化切片,对比观察各组不同时间点海马齿状回和皮层神经元MAG蛋白表达的变化。【结果】两组海马齿状回和皮层均有MAG蛋白表达。HIBD组HI后24 h、48 h海马齿状回MAG表达较假手术组显著性升高(P<0.01或0.05),HI后72 h7、d海马齿状回MAG表达较假手术组显著性下降(P均<0.05)。HIBD组HI后24 h4、8 h7、2 h皮层MAG表达较假手术组显著升高(P<0.001或0.05),在HI后7 d皮层MAG表达较相同时间点假手术组显著性下降(P<0.05)。【结论】MAG蛋白的表达量因鼠脑的区域不同而有所差异,随着日龄的增加,各有其变化规律。当受到缺氧缺血损伤时,MAG蛋白的表达强度以及波动规律也发生改变。因此推论MAG测定将会对新生儿缺氧缺血性脑病的早期诊断(HI后24 h、48 h)、病程判断方面具有应用价值。

【Objective】 To probe the expression of myelin-associated glycoprotein（MAG protein） at hippocampus dentate gyrus and cortex in hypoxic ischemic brain damaged（HIBD） newborn rats. 【Methods】 64 healthy 7 days old Sprague-Dawley rats were randomly divided into tow groups,the sham-operation and the HIBD mode group.The changes in expression strength of MAG protein at hippocampus dentate gyrus and cortex were observed by immunohistochemical method after hypoxic ischemia,HI 24 h,48 h,72 h,and 7 days. 【Results】 MAG protein was expressed both in hippocampus dentate gyrus and cortex.The mean optical density of MAG were different significantly between two groups at HI 24 h,48 h,72 h and 7days,P0.05,including P24h 0.01 in hippocampal dentate gyrus and P24h 0.001 in cortex.Either in the sham-operation or the HIBD mode group,the expression strength of MAG protein was varied in deferent pattern in hippocampus dentate gyrus and cortex 【Conclusions】 The expression strength of MAG protein is varied in different cerebral area.With aging,the expression strength of MAG protein is changed in unlike pattern.Therefore,in newborn rats which were injured with HI,the expression strength of MAG protein and the pattern are changed.It means that in certain time range,the changes in the expression of MAG protein reflects the neurons in some area are damaged by HI.Further more it could be concluded that the changes of MAG protein may play a role in early diagnosis of HIE in newborns.