IL-17A 通过破坏血脑屏障导致老年小鼠围手术期神经认知障碍。
IL-17A contributes to perioperative neurocognitive disorders through blood-brain barrier disruption in aged mice.
机构信息
Department of Anesthesiology, The First Affiliated Hospital of Nanjing Medical University, Jiangsu, 210029, People's Republic of China.
出版信息
J Neuroinflammation. 2018 Nov 30;15(1):332. doi: 10.1186/s12974-018-1374-3.
BACKGROUND
Perioperative neurocognitive disorders (PND) occur frequently after surgery, especially in aged patients. Surgery-induced neuroinflammation and blood-brain barrier (BBB) dysfunction play a crucial role in the pathogenesis of PND. Interleukin-17A (IL-17A) increases after surgical stress and will be involved in BBB dysfunction. However, the effect of IL-17A on BBB function during PND remains poorly understood.
METHODS
Male wild-type C57BL/6J mice (15 months old) received tibial fracture surgery and fixation to establish the PND model. All the mice were injected intraperitoneally with an IL-17A-neutralizing antibody (Abs) or isotype-control Abs 30 min before tibial fracture surgery. Animal behaviour tests conducted 24 h after surgery included the contextual fear conditioning and Y maze tests. Serum and hippocampus IL-17A levels and hippocampus IL-6 and IL-1β levels were detected by ELISA. BBB function was detected by Evans blue (EB) test. Hippocampus matrix metalloproteinase-2 (MMP-2)- and MMP-9-positive cells were detected by immunohistochemistry. Hippocampus albumin, occludin, claudin-5 and IL-17A receptors were detected by Western blot. For the in vitro experiment, bEnd.3 cells were incubated with IL-17A. Cell IL-17A receptors were detected by immunofluorescence. Cellular MMP-2, MMP-9, occludin, and claudin-5 were detected by Western blot.
RESULTS
Tibial fracture surgery promoted memory impairment, increased levels of IL-17A and IL-17A receptors, inflammatory factor production and BBB dysfunction. IL-17A Abs inhibited this effect, including improving memory function, decreasing inflammatory factor production and alleviating BBB disruption, indicated by decreased tight junctions (TJs) and increased MMPs after surgery. The in vitro study suggested that recombinant IL-17A could upregulate the expression of IL-17A receptors, decrease TJs and increase the level of MMPs in bEnd.3 cells.
CONCLUSIONS
Our results suggested that IL-17A-promoted BBB disruption might play an important role in the pathogenesis of PND.
背景
围手术期神经认知障碍（PND）在手术后很常见，尤其是在老年患者中。手术引起的神经炎症和血脑屏障（BBB）功能障碍在 PND 的发病机制中起着关键作用。白细胞介素 17A（IL-17A）在手术应激后增加，并将参与 BBB 功能障碍。然而，IL-17A 在 PND 期间对 BBB 功能的影响仍知之甚少。
方法
雄性野生型 C57BL/6J 小鼠（15 个月龄）接受胫骨骨折手术和固定以建立 PND 模型。所有小鼠均在胫骨骨折手术前 30 分钟经腹腔注射白细胞介素 17A 中和抗体（Abs）或同型对照 Abs。手术后 24 小时进行动物行为测试，包括情景恐惧条件反射和 Y 迷宫测试。通过 ELISA 检测血清和海马 IL-17A 水平以及海马 IL-6 和 IL-1β 水平。通过 Evans 蓝（EB）试验检测 BBB 功能。通过免疫组织化学检测海马基质金属蛋白酶-2（MMP-2）和 MMP-9 阳性细胞。通过 Western blot 检测海马白蛋白、occludin、claudin-5 和 IL-17A 受体。对于体外实验，用 IL-17A 孵育 bEnd.3 细胞。通过免疫荧光检测细胞 IL-17A 受体。通过 Western blot 检测细胞 MMP-2、MMP-9、occludin 和 claudin-5。
结果
胫骨骨折手术促进了记忆障碍，增加了 IL-17A 和 IL-17A 受体、炎症因子产生和 BBB 功能障碍的水平。IL-17A Abs 抑制了这种作用，包括改善记忆功能、减少炎症因子产生和减轻手术后 BBB 破坏，表现为手术后紧密连接（TJs）减少和 MMPs 增加。体外研究表明，重组 IL-17A 可上调 bEnd.3 细胞中 IL-17A 受体的表达，减少 TJs，并增加 MMPs 的水平。
结论
我们的结果表明，IL-17A 促进的 BBB 破坏可能在 PND 的发病机制中起重要作用。
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