Department of Anesthesiology, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
Department of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China.
Mol Med Rep. 2020 Aug;22(2):1391-1399. doi: 10.3892/mmr.2020.11244. Epub 2020 Jun 16.
Postoperative cognitive dysfunction (POCD) is a prevalent neurocognitive disorder following surgery and anesthesia, particularly in elderly patients. Isoflurane is a widely used anesthetic agent, which is associated with the development of POCD; however, the precise mechanisms remain unclear. In the present study, aged rats were exposed to 2% isoflurane to establish a POCD model. The expression of PYRIN‑containing Apaf1‑like protein 1 (PYPAF1) was knocked down using a lentivirus containing specific short hairpin RNA. Subsequently, the spatial learning ability of rats was assessed using the Morris water maze. In addition, mRNA and protein expression levels were detected using reverse transcription‑quantitative PCR and western blot analysis, respectively. Immunofluorescence double staining was also used to determine the expression of PYPAF1 and Iba‑1 in the hippocampus. Neural apoptosis was observed using TUNEL‑NeuN double staining. The results revealed that isoflurane exposure impaired the spatial learning ability of rats, while PYPAF1 knockdown alleviated cognitive impairment. In addition, isoflurane exposure induced activation of the PYPAF1 inflammasome, as evidenced by elevated expression of PYPAF1 and apoptosis‑associated speck‑like protein containing a caspase recruitment domain, while silencing of PYPAF1 partially reversed this effect. Furthermore, isoflurane exposure promoted the activation of microglia and caspase‑1, and the secretion of interleukin (IL)‑1β and IL‑18, all of which were alleviated following PYPAF1 silencing. Moreover, isoflurane exposure induced neuronal apoptosis, elevated the levels of Bax and cleaved caspase‑3, and inhibited the expression of Bcl‑2; all of these effects were partially abrogated following PYPAF1 silencing. In conclusion, the results of the present study indicated that PYPAF1 silencing partially abolished isoflurane‑induced cognitive impairment, neuroinflammation and neuronal apoptosis. Therefore, PYPAF1 may be a potential therapeutic target for treatment of POCD.
术后认知功能障碍（POCD）是手术后和麻醉后普遍存在的神经认知障碍，特别是在老年患者中。异氟烷是一种广泛使用的麻醉剂，与 POCD 的发生有关，但确切的机制尚不清楚。在本研究中，使用 2%异氟烷使老年大鼠暴露于其中，以建立 POCD 模型。使用含有特定短发夹 RNA 的慢病毒敲低 PYPAF1 的表达。随后，使用 Morris 水迷宫评估大鼠的空间学习能力。此外，使用逆转录-定量 PCR 和 Western blot 分析分别检测 mRNA 和蛋白表达水平。还使用免疫荧光双重染色法来确定海马中 PYPAF1 和 Iba-1 的表达。使用 TUNEL-NeuN 双重染色法观察神经细胞凋亡。结果显示，异氟烷暴露损害了大鼠的空间学习能力，而 PYPAF1 敲低减轻了认知障碍。此外，异氟烷暴露诱导了 PYPAF1 炎性小体的激活，表现为 PYPAF1 和包含半胱天冬酶募集结构域的凋亡相关斑点样蛋白的表达升高，而沉默 PYPAF1 部分逆转了这种作用。此外，异氟烷暴露促进了小胶质细胞和 caspase-1 的激活以及白细胞介素（IL）-1β和 IL-18 的分泌，这些作用在沉默 PYPAF1 后均得到缓解。此外，异氟烷暴露诱导神经元凋亡，增加 Bax 和 cleaved caspase-3 的水平，并抑制 Bcl-2 的表达；沉默 PYPAF1 后，这些作用部分被阻断。综上所述，本研究结果表明，沉默 PYPAF1 部分消除了异氟烷诱导的认知障碍、神经炎症和神经元凋亡。因此，PYPAF1 可能是治疗 POCD 的潜在治疗靶点。
