Chen Keyan, Wang Nan, Diao Yugang, Dong Wanwei, Sun YingJie, Liu Lidan, Wu Xiuying
Department of Laboratory Animal Science, China Medical University, Shenyang, China.
The people's Hospital of Liaoning Province, Department of Neurology inspection, the people's Hospital of Liaoning Province, Shenyang, China.
Cell Physiol Biochem. 2017;43(4):1634-1647. doi: 10.1159/000484024. Epub 2017 Oct 17.
BACKGROUND/AIMS: Cardiopulmonary bypass (CPB) is prone to inducing brain injury during open heart surgery. A hydrogen-rich solution (HRS) can prevent oxidation and apoptosis, and inhibit inflammation. This study investigated effects of HRS on brain injury induced by CPB and regulatory mechanisms of the PI3K/Akt/GSK3β signaling pathway.
A rat CPB model and an in vitro cell hypoxia model were established. After HRS treatment, Rat behavior was measured using neurological deficit score; Evans blue (EB) was used to assess permeability of the blood-brain barrier (BBB); HE staining was used to observe pathological changes; Inflammatory factors and brain injury markers were detected by ELISA; the PI3K/Akt/GSK3β pathway-related proteins and apoptosis were assessed by western blot, immunohistochemistry and qRT -PCR analyses of brain tissue and neurons.
After CPB, brain tissue anatomy was disordered, and cell structure was abnormal. Brain tissue EB content increased. There was an increase in the number of apoptotic cells, an increase in expression of Bax and caspase-3, a decrease in expression of Bcl2, and increases in levels of Akt, GSK3β, P-Akt, and P-GSK3β in brain tissue. HRS treatment attenuated the inflammatory reaction ,brain tissue EB content was significantly reduced and significantly decreased expression levels of Bax, caspase-3, Akt, GSK3β, P-Akt, and P-GSK3β in the brain. After adding the PI3K signaling pathway inhibitor, LY294002, to rat cerebral microvascular endothelial cells (CMECs), HRS could reduce activated Akt expression and downstream regulatory gene phosphorylation of GSK3β expression, and inhibit CMEC apoptosis.
The PI3K/Akt/GSK3β signaling pathway plays an important role in the mechanism of CPB-induced brain injury. HRS can reduce CPB-induced brain injury and inhibit CMEC apoptosis through the PI3K/Akt/GSK3β signaling pathway.
背景/目的：体外循环（CPB）在心脏直视手术中易引发脑损伤。富氢溶液（HRS）可预防氧化和细胞凋亡，并抑制炎症反应。本研究探讨了HRS对CPB诱导的脑损伤的影响以及PI3K/Akt/GSK3β信号通路的调控机制。
建立大鼠CPB模型和体外细胞缺氧模型。HRS处理后，采用神经功能缺损评分测量大鼠行为；用伊文思蓝（EB）评估血脑屏障（BBB）的通透性；苏木精-伊红（HE）染色观察病理变化；酶联免疫吸附测定（ELISA）法检测炎症因子和脑损伤标志物；通过蛋白质免疫印迹法、免疫组织化学法以及对脑组织和神经元进行实时定量逆转录聚合酶链反应（qRT-PCR）分析，评估PI3K/Akt/GSK3β信号通路相关蛋白和细胞凋亡情况。
CPB后，脑组织解剖结构紊乱，细胞结构异常。脑组织EB含量增加。凋亡细胞数量增多，促凋亡蛋白Bax和半胱天冬酶-3（caspase-3）表达增加，抗凋亡蛋白Bcl2表达减少，脑组织中蛋白激酶B（Akt）、糖原合成酶激酶-3β（GSK3β）、磷酸化Akt（P-Akt）和磷酸化GSK3β（P-GSK3β）水平升高。HRS处理减轻了炎症反应，脑组织EB含量显著降低，脑组织中Bax、caspase-3、Akt、GSK3β、P-Akt和P-GSK3β的表达水平显著下降。向大鼠脑微血管内皮细胞（CMECs）中加入PI3K信号通路抑制剂LY294002后，HRS可降低活化的Akt表达以及GSK3β表达的下游调节基因磷酸化，并抑制CMEC凋亡。
PI3K/Akt/GSK3β信号通路在CPB诱导的脑损伤机制中起重要作用。HRS可通过PI3K/Akt/GSK3β信号通路减轻CPB诱导的脑损伤并抑制CMEC凋亡。
