Src激酶在正常发育和未成熟大鼠缺氧缺血脑白质损伤中的表达变化

Expressions of Src kinases in normal developing brain and immature brains with hypoxic-ischemic white matter injury of rats

目的研究大鼠正常发育脑中和缺氧缺血性脑白质损伤中Src激酶活化的表达。方法对出生后第3天SD大鼠幼仔进行右颈总动脉结扎,然后进行2.5 h缺氧(6%氧气)造模。通过苏木精-伊红(HE)染色、蛋白免疫印迹和免疫荧光染色观察神经病理学改变。收集出生后6、10、17天对照组和缺氧缺血(hypoxia-ischemia,HI)组大鼠的脑组织,通过蛋白质免疫印迹和免疫荧光染色评估磷酸化Src激酶的表达水平,并通过三重免疫荧光染色明确磷酸化Src激酶与少突胶质细胞(oligodendrocyte,OL)共定位情况。结果在正常发育的对照组大鼠中,脑内磷酸化Src激酶的表达在出生后6和10天时处于高峰期。磷酸化的Src主要与成熟的OLs共定位,而在少突胶质前体细胞中很少观察到与其共定位的现象。在建立的3日龄大鼠缺氧缺血脑白质损伤模型中,磷酸化Src激酶在损伤后3天时(生后6天)表达显著下降(P=0.0007,n=6~7/组)。在损伤后7天(生后10天)、14天(生后17天)时恢复到对照组水平,与对照组间差异无统计学意义(n=3/组)。结论在正常发育大鼠脑中磷酸化Src激酶的活化表达有时间节律,而在HI损伤后磷酸化Src激酶表达减少。

Objective To investigate the expressions of phosphorylated Src kinase in normal developing brains and immature brains with hypoxic-ischemic white matter injury of rats.Methods Three-day-old Sprague-Dawley rat pups were subjected to right carotid artery ligation,followed by 2.5 h of hypoxia(6%oxygen).The neuropathological changes were observed by hematoxylin-eosin(HE)staining,Western blot and immunofluorescence.Brain tissues were collected from control and hypoxia-ischemia(HI)group rats at postnatal day 6,10 and 17.Expression of phosphorylated Src was evaluated by Western blot and immunofluorescence.The relationship of phosphorylated Src kinases and oligodendrocytes(OLs)was evaluated by triple immunofluorescence staining.Results In the control group,the expression of phosphorylated Src kinases peaked at 6 and 10 days after birth.Phosphorylated Src kinases was predominantly present in mature OLs,which was rarely observed in oligodendrocyte precursor cells.In the 3-day rat hypoxic-ischemic white matter injury model,phosphorylated Src kinases decreased significantly 3 days after injury(6 days after birth)(P=0.0007,n=6-7 for each group).At 7 days after injury(10 days after birth)and 14 days(17 days after birth)after injury,phosphorylated Src kinases returned to the level of control group,and there was no statistically significant difference between control group and HI group(n=3 for each group).Conclusion In normal developing brains of rats,the expression of phosphorylated Src kinases has a time rhythm and decreases after HI injury.