血脑屏障P-糖蛋白调节异氟醚所致β淀粉样蛋白增高和凋亡的研究

There is an open controversy on the role of general anesthesia and surgery in the neuropathogenesis of Alzheimer's disease. However, recent research studies have suggested that the inhaled anesthetic isoflurane promotes neurotoxicity by increasing β-amyloid aggregation and inducing apoptosis. β-amyloid-induced neurotoxicity is a main component of Alzheimer's disease neuropathogenesis. Recently, we reported several transcriptional regulators of p-glycoprotein in blood-brain barrier, and a few signal pathways of p-glycoprotein in blood-retinal barrier. More recently, in preliminary experiments, we found that isoflurane inhibits expression and activity of p-glycoprotein in blood-retinal barrier. Therefore, we now use the β-amyloid transport-clearance theory to hypothesize that the activation of p-glycoprotein in blood-brain barrier will prevent the β-amyloid aggregation and neuronal damage induced and/or enhanced by isoflurane. First, using our established in vitro blood-brain barrier models, we will carry on our investigation in the alterations of β-amyloid-efflux transporters and the regulatory mechanism of p-glycoprotein impacted by isoflurane. Second, we will exam the alterations of p-glycoprotein pathway, integrate transport process and neurotoxicity of β-amyloid following isoflurane anesthesia in na?ve mice. Finally, using Tg2576 transgenic mouse model of human cerebral amyloid pathology, we will adjust the p-glycoprotein signaling pathway to assess the role that p-glycoprotein plays in the enhanced neurotoxicity of β-amyloid after isoflurane anesthesia, and the role that p-glycoprotein involves in amyloid pathology. This project will potentially tell us whether p-glycoprotein in blood-brain barrier is involved in the neurotoxicity of β-amyloid enhanced by isoflurane anesthesia, and also have implications in the investigations in neurotoxicity of inhaled anesthetics, which may eventually lead to safer anesthesia care for patients, especially senior and Alzheimer's patients.

全身麻醉/手术促发阿尔茨海默氏病的争论方兴未艾，吸入麻醉剂异氟醚诱导β淀粉样蛋白增高和凋亡的证据日益增多。已报道血脑屏障细胞的P-糖蛋白（P-gp）调节因子，和血视网膜屏障P-p信号介导机制，初步发现异氟醚抑制血脑屏障P-gp表达与活性。现运用β淀粉样蛋白转运清除学说，推测血脑屏障P-gp是异氟醚诱导神经毒性作用的潜在干预靶点。拟继续采用已有血脑屏障模型，深入观察异氟醚体外处理对外排泵表达和P-gp活性的影响；随后，将观察异氟醚麻醉对小鼠血脑屏障P-gp表达、活性、转运β淀粉样蛋白过程与效果和凋亡水平的影响。最后，将采用阿尔茨海默氏病转基因小鼠，通过调节P-gp信号通路，全面观察异氟醚麻醉后小鼠脑内β淀粉样蛋白外排与凋亡水平的改变，进一步验证假说。可望初步明确血脑屏障P-gp是否参与异氟醚麻醉的神经毒性作用；也有助于阐明吸入麻醉剂的神经毒性作用机制和对β淀粉样蛋白易感者的可能影响。

吸入麻醉剂异氟醚诱导β淀粉样蛋白增高和凋亡的证据日益增多。本项目观察异氟醚处理对中枢神经系统，尤其是血脑屏障体外和在体模型，五种特定的、相关的Aβ相关转运受体（包括P-gp、LRP1、RAGE、GLUT-1和BCRP）的影响，包括活性和表达的影响，初步发现对血脑屏障外排泵表达和P-gp活性的影响，可能是异氟醚麻醉导致脑内β淀粉样蛋白积聚和凋亡的重要机制，具有潜在的干预价值，相关工作成果正在进行总结。我们还对异氟醚预处理抑制人单核细胞白血病细胞THP-1炎症反应及其ERK MAPK信号通路机制、异氟醚预处理通过上调组蛋白去乙酰化酶产生抗炎作用，和脊髓背角卫星胶质细胞P2X7受体上调促发SMIR诱导疼痛，进行了深入观察和探讨。项目还对静脉麻醉药物丙泊酚对未成熟神经元的凋亡影响及其TRPC6机制进行了研究。本项目已经发表SCI论文4篇，正在撰写论文3篇，带动两位成员晋升高级职称、一位获得正高三级，一位硕士生导师和一位临床博士学位导师，还有7名硕士生毕业和多名博士生在读，另有多个后续项目获得省市资助。