新生大鼠脑白质损害模型神经胶质细胞的凋亡及MK2、Nogo-B的表达研究

Apoptosis of Neuroglial Cell and Expressions of Neurite Outgrowth Inhibitor B and MAP Kinase-activated Protein Kinase 2 in White Matter Damage Model of Newborn Rat Brain

目的观察2日龄(P2)新生大鼠脑白质损害(WMD)后神经胶质细胞凋亡及丝裂原活化蛋白激酶活化蛋白激酶2(MK2)、Nogo-B的变化;探讨神经胶质细胞凋亡与MK2、Nogo-B变化的时相关系。方法制备新生鼠WMD模型,分别于WMD后30 min、1 h、4 h、12 h、1 d、3 d、7 d、14 d及21 d处死大鼠,TUNEL法检测脑白质神经细胞凋亡,免疫组化(SP)法检测Nogo-B蛋白的表达,原位杂交(POD法)检测MK2 mRNA表达。结果WMD组大鼠凋亡指数在缺氧缺血4 h、12 h、1 d、3 d、7 d组与对照组相比,差异有统计学意义(P<0.05);WMD后1 h MK2mRNA在脑室周围白质及胼胝体区表达上调,并于损伤后3 d达到高峰。Nogo-B在WMD后12 h表达增加,3 d达高峰,在12 h、1 d、3 d、7 d的表达与对照组相比,差异有统计学意义(P<0.05)。结论MK2、Nogo-B在新生大鼠脑白质损害时表达增高,提示其参与了脑白质损害。

Objective To observe and explore the apoptosis of neuroglial cell and the expression changes of neurite outgrowth inhibitor B （Nogo-B） and MAP kinase-activated protein kinase 2 （MK2） in SD rats with white matter damage （WMD）. Methods The WMD model of newborn rat was established for this study, and then the pups were respectively killed at 30 min, 1 h, 4 h, 12 h, 1 d, 3 d, 7 d, 14 d, 21 d after WMD. The apoptosis of neuroglial cells was investigated by TUNEL method; the changes of Nogo-B expression in white matter were investigated by immunohistochemical technique; the changes of expression of MK2 mRNA in white matter were measured by in situ hybridization. Results TUNEL result showed the number of apoptotic cells increased at 4 h and peaked at 3 d, decreased at 7 d after WMD of newborn rat ; the expression of MK2 mRNA began to increase at 1 h and reached a maximum at 3 d （P〈0.05） ; the expression of Nogo-B in periventricular white matter and corpus callosum of WMD rat was up-regulated at 12 h and peaked at 3 d after cerebral white matter damage, displaying significant differences at 12 h, 1 d, 3 d and 7 d when the Nogo-B expression in WMD rat compared with that observed in the control （P〈0. 05）. Conclusion Nogo-B and MK2 can participate in pathogenesis of white matter damage in newborn rat.