Liu Li-Fang, Hu Yun, Liu Yi-Nuo, Shi De-Wen, Liu Chang, Da Xin, Zhu Si-Hui, Zhu Qian-Yun, Zhang Ji-Qian, Xu Guang-Hong
Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Key Laboratory of Anesthesia and Perioperative Medicine of Anhui Higher Education Institutes, Hefei, China.
Front Aging Neurosci. 2022 Oct 19;14:1021129. doi: 10.3389/fnagi.2022.1021129. eCollection 2022.
Postoperative delirium (POD) is common in the elderly and is associated with poor clinical outcomes. Reactive oxygen species (ROS) and blood-brain barrier (BBB) damage have been implicated in the development of POD, but the association between these two factors and the potential mechanism is not clear. Cyclophilin A (CypA) is a specifically chemotactic leukocyte factor that can be secreted in response to ROS, which activates matrix metalloproteinase 9 (MMP9) and mediates BBB breakdown. We, therefore, hypothesized that ROS may contribute to anesthesia/surgery-induced BBB damage and delirium-like behavior the CypA/MMP9 pathway. To test these hypotheses, 16-month-old mice were subjected to laparotomy under 3% sevoflurane anesthesia (anesthesia/surgery) for 3 h. ROS scavenger (N-acetyl-cysteine) and CypA inhibitor (Cyclosporin A) were used 0.5 h before anesthesia/surgery. A battery of behavior tests (buried food test, open field test, and Y maze test) was employed to evaluate behavioral changes at 24 h before and after surgery in the mice. Levels of tight junction proteins, CypA, MMP9, postsynaptic density protein (PSD)-95, and synaptophysin in the prefrontal cortex were assessed by western blotting. The amounts of ROS and IgG in the cortex of mice were observed by fluorescent staining. The concentration of S100β in the serum was detected by ELISA. ROS scavenger prevented the reduction in TJ proteins and restored the permeability of BBB as well as reduced the levels of CypA/MMP9, and further alleviated delirium-like behavior induced by anesthesia/surgery. Furthermore, the CypA inhibitor abolished the increased levels of CypA/MMP, which reversed BBB damage and ameliorated delirium-like behavior caused by ROS accumulation. Our findings demonstrated that ROS may participate in regulating BBB permeability in aged mice with POD the CypA/MMP9 pathway, suggesting that CypA may be a potential molecular target for preventing POD.
术后谵妄（POD）在老年人中很常见，且与不良临床预后相关。活性氧（ROS）和血脑屏障（BBB）损伤与POD的发生有关，但这两个因素之间的关联及潜在机制尚不清楚。亲环素A（CypA）是一种特异性趋化白细胞因子，可响应ROS分泌，激活基质金属蛋白酶9（MMP9）并介导血脑屏障破坏。因此，我们假设ROS可能通过CypA/MMP9途径导致麻醉/手术引起的血脑屏障损伤和谵妄样行为。为了验证这些假设，对16月龄小鼠在3%七氟醚麻醉下进行剖腹手术（麻醉/手术）3小时。在麻醉/手术前0.5小时使用ROS清除剂（N-乙酰半胱氨酸）和CypA抑制剂（环孢素A）。采用一系列行为测试（埋藏食物试验、旷场试验和Y迷宫试验）评估小鼠手术前后24小时的行为变化。通过蛋白质免疫印迹法评估前额叶皮质中紧密连接蛋白、CypA、MMP9、突触后密度蛋白（PSD）-95和突触素的水平。通过荧光染色观察小鼠皮质中ROS和IgG的含量。通过酶联免疫吸附测定法检测血清中S100β的浓度。ROS清除剂可防止紧密连接蛋白减少，恢复血脑屏障通透性，并降低CypA/MMP9水平，进一步减轻麻醉/手术诱导的谵妄样行为。此外，CypA抑制剂消除了CypA/MMP水平的升高，逆转了血脑屏障损伤，并改善了由ROS积累引起的谵妄样行为。我们的研究结果表明，ROS可能通过CypA/MMP9途径参与调节老年POD小鼠的血脑屏障通透性，提示CypA可能是预防POD的潜在分子靶点。
