Department of Anesthesiology, Pain and Perioperative Medicine, The First Affiliated Hospital of Zhengzhou University, No. 1, Longhu Central Ring Road, Zhengzhou, 450000, Henan Province, China.
Department of Anesthesiology, Pain and Perioperative Medicine, Henan Provincial People's Hospital, Zhengzhou, 450000, China.
Neurochem Res. 2022 Nov;47(11):3490-3505. doi: 10.1007/s11064-022-03712-y. Epub 2022 Aug 30.
Dexmedetomidine (Dex) plays protective effects on brain ischemia-reperfusion (I/R) injury, but its mechanism remains unclear. In this study, we aimed to investigate whether Dex protects neurons against I/R injury by activating SIRT3 mediated autophagy. The oxygen glucose deprivation-reperfusion (OGD/R) model was constructed in HT22 cells. Different doses of Dex (50 ng/mL, 100 ng/mL and 500 ng/mL) were treated to observe the changes of autophagy and SIRT3 expression. Further, the mimic of SIRT3 and SIRT3 inhibitor were used to analyze the effects of Dex on the SIRT3 expression in HT22 cells. Additionally, the autophagy inhibitor and AMPK inhibitor were used to analyze the effects of Dex on SIRT3 mediated autophagy. The cells viability, oxidative stress and ATP were observed using assay kits. The mitochondrial membrane potential (MMP) and death were analyzed by flow cytometry. The degree of autophagy was observed by acridine orange staining. Western blotting was used to analyze the expression of autophagy related proteins and AMPK/mTOR pathway related proteins. After Dex treatment, the OGD/R induced cell injury was significantly improved through decreasing the levels of LDH and HO, increasing levels of ATP and MMP. Furthermore, Dex increased the degree of autophagy and expression of SIRT3 in OGD/R injured cells. Through overexpression of SIRT3, the OGD/R induced cell injury was also clearly improved. But the SIRT3 inhibitor or autophagy inhibitor covered the roles of Dex. Additionally, AMPK inhibitor played an opposite role compared with the effects of Dex treatment. From this study, the protection mechanism of Dex on neurons I/R injury might related to the activation of SIRT3 mediated autophagy.
右美托咪定（Dex）对脑缺血再灌注（I / R）损伤具有保护作用，但作用机制尚不清楚。本研究旨在探讨右美托咪定是否通过激活 SIRT3 介导的自噬来保护神经元免受 I / R 损伤。在 HT22 细胞中构建氧葡萄糖剥夺再灌注（OGD / R）模型。用不同剂量的 Dex（50ng/mL、100ng/mL 和 500ng/mL）处理以观察自噬和 SIRT3 表达的变化。进一步，使用 SIRT3 的模拟物和 SIRT3 抑制剂来分析 Dex 对 HT22 细胞中 SIRT3 表达的影响。此外，使用自噬抑制剂和 AMPK 抑制剂来分析 Dex 对 SIRT3 介导的自噬的影响。通过测定试剂盒观察细胞活力，氧化应激和 ATP 的变化。通过流式细胞术分析线粒体膜电位（MMP）和死亡。通过吖啶橙染色观察自噬程度。Western blotting 用于分析自噬相关蛋白和 AMPK / mTOR 通路相关蛋白的表达。Dex 处理后，通过降低 LDH 和 HO 的水平，增加 ATP 和 MMP 的水平，可明显改善 OGD / R 诱导的细胞损伤。此外，Dex 增加了 OGD / R 损伤细胞中自噬的程度和 SIRT3 的表达。通过过表达 SIRT3，OGD / R 诱导的细胞损伤也明显改善。但是 SIRT3 抑制剂或自噬抑制剂掩盖了 Dex 的作用。此外，与 Dex 处理的作用相反，AMPK 抑制剂发挥了相反的作用。从这项研究中可以看出，Dex 对神经元 I / R 损伤的保护机制可能与激活 SIRT3 介导的自噬有关。
