缺血缺氧性脑病（HIE）是新生儿致死致残的主要原因，探索其发生机制，寻找其血清学监测指标，具有重要的研究意义。目前的研究发现，HIE发生时脑室周围白质(PWM)呈选择性易损，其中炎症反应、谷氨酸代谢紊乱可能起关键作用，但机制不清。前期研究首次报道阿米巴样小胶质细胞（AMC）表达ATP受体P2X4，缺氧后其表达上调，并伴随谷氨酸转运体1（EAAT1）表达水平降低。但二者间的关系，及P2X4对其可能的调控机制迄今未见报道。脑损伤时脑内Tau蛋白异常表达并释放入血，且与EAAT1的表达间可能存在密切联系，但其在HIE中的意义尚不清楚。本项目拟对P2X4进行受体靶向抑制，研究对新生鼠缺氧后PWM区域谷氨酸浓度、EAAT1、炎症介质表达的作用；重点以Tau蛋白作为血清学指标，揭示其对PWM损伤可能的监测作用。从而为HIE的发生机制提供新证据，为临床寻找监测HIE后脑损伤程度的血清学指标提供新依据。

Hypoxic and ischemic encephalopathy (HIE) is gaining interest by many because of its high mortality and disability rate. Indeed, the modulatory mechanism and serum biomarkers related to HIE have been the focus of many studies. The defining feature of neuropathology in HIE is the injury susceptibility of the periventricular white matter (PWM). It has been reported that inflammation and glutamate metabolic disorder are involved in the PWM damage after hypoxia in neonatal brain. The activation of amoeboid microglial cells (AMC) have been linked to the inflammatory response in PWM after hypoxia in neonatal. On the other hand, the underlying mechanism leading to AMC activation has remained uncertain. In our previous study,we showed that AMC expressed ATP receptors, namely, P2X4 notably the first-named receptor in hypoxia in neonatal brain. It was suggested that the P2X4 may be linked to regulation of AMC activation for production of proinflammatory cytokines in hypoxic exposure. Recently it has been reported that there is a crosstalk between the purinic signal and glutamate metabolic disorder. However, the putative roles of P2X4 in regulating glutamate metabolism in PWM after hypoxia in neonatal brain has remained to be further explored. Tau is an microtubules assosiated protein whose expression is localized in the axons of neurons. Some studies have reported that Tau can be released into the prepherial blood after cerebral injury. A recent study has reported that Tau expression is increased as a result of reduced glutamate trasporter expression after brain ischemia. We have reported previously that glutamate transporter 1 expression was decreased after hypoxia in neonatal rats. In the present study, we first aim to invetigate the underlying mechanism of P2X4 in its regulation of glutamate release in the PWM. Along with this, the potential relationship between the glutamate metabolism and serum Tau protein after hypoxia in rat pups will be investigated. P2X4 will be blocked by pyridoxal phosphate-6-azo (benzene-2, 4-disulfonic acid) tetrasodium salt hydrate (a slective blockade for P2X1-3,5-7) and 2', 3'-0-(2, 4, 6-Trinitrophenyl) adenosine 5'-triphosphate (a slective blokcade for P2X1-4) by intraperitoneal injection wihtin 4 hours after hypoxic exposure in neonatal rats. To confirm the blockade efficiency of P2X4, the differences between the hypoxic and blokade groups will be compared. An ultra-high performance liquid chromatography-tandem mass-spectrometry method will be adopted to meaurse the concentration of glutamate in PWM. Glutamate concentration and cytokine expression levels will be used to evaluate the blockade effciency. Tau and phosphate Tau will also be tested in the seurm and brain at the same time points after hypoxia and P2X4 blockade. It is hoped the information obtained would provide to basis for designing of a new therapeutic target and potential serum biomarker for hypoxia induced injuries in the postnatal brain.