Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, China.
Anesth Analg. 2010 Aug;111(2):506-14. doi: 10.1213/ANE.0b013e3181e45519. Epub 2010 Jul 7.
In this study, we sought to clarify the role of inhibiting ubiquitin-conjugated protein aggregation in the formation of a neuroprotective effect after isoflurane preconditioning using a transient global cerebral ischemia-reperfusion injury mouse model.
C57BL/6 mice were randomly assigned to 3 groups (isoflurane preconditioning [IsoPC] group, control [Con] group, and sham group, n = 24 in each group). Mice in the IsoPC group and sham group were placed in a chamber and pretreated with isoflurane (1.2% isoflurane, 98% O(2), 1 hour/day) for 5 days. Mice in the Con group were placed in the same chamber but pretreated with oxygen only (98% O(2), 2% N(2), 1 hour/day) for 5 days. Twenty-four hours after the last preconditioning day, bilateral common carotid artery occlusion was performed as a model of global cerebral ischemia for 20 minutes in the IsoPC group and Con group. The total motor scores, number of viable neurons in the CA1 region of the hippocampus, and expression levels of conjugated ubiquitin or free ubiquitin were assessed by neurological assessment, immunohistochemistry, and Western blotting (at 24 and 72 hours) after reperfusion, respectively.
The total motor scores in the IsoPC group were better than the Con group (P < 0.05). Morphological observations showed that the IsoPC group had better neuron structure than in the Con group. The numbers of viable neurons in the CA1 region were significantly increased by isoflurane preconditioning compared with those in the Con group (P < 0.05). The numbers of TUNEL-positive neurons in the CA1 region were significantly decreased after isoflurane preconditioning. The density of conjugated ubiquitin staining in the CA1 region of the IsoPC group was significantly lower than in the Con group (P < 0.05) and the expression of conjugated ubiquitin in the IsoPC group was lower than in the Con group (P < 0.05).
Inhibition of ubiquitin-conjugated protein aggregation may have an essential role in inducing cerebral ischemic tolerance by isoflurane preconditioning in a transient global cerebral ischemia-reperfusion injury mouse model.
在这项研究中，我们使用短暂性全脑缺血再灌注损伤小鼠模型，旨在阐明抑制泛素化蛋白聚集体在异氟烷预处理后形成神经保护作用中的作用。
将 C57BL/6 小鼠随机分为 3 组（异氟烷预处理[IsoPC]组、对照组[Con]组和假手术组，每组 24 只）。IsoPC 组和假手术组小鼠置于室中，用异氟烷（1.2%异氟烷、98%氧气，1 小时/天）预处理 5 天。Con 组小鼠置于相同的室中，但仅用氧气预处理（98%氧气、2%氮气，1 小时/天）5 天。最后一次预处理后 24 小时，IsoPC 组和 Con 组进行双侧颈总动脉闭塞，作为全脑缺血 20 分钟的模型。通过神经学评估、免疫组织化学和 Western blot（再灌注后 24 和 72 小时）分别评估总运动评分、海马 CA1 区存活神经元数量以及缀合泛素或游离泛素的表达水平。
IsoPC 组的总运动评分优于 Con 组（P<0.05）。形态学观察表明，IsoPC 组的神经元结构优于 Con 组。与 Con 组相比，异氟烷预处理可显著增加 CA1 区存活神经元的数量（P<0.05）。异氟烷预处理后 TUNEL 阳性神经元数量明显减少。IsoPC 组 CA1 区缀合泛素染色密度明显低于 Con 组（P<0.05），IsoPC 组缀合泛素的表达低于 Con 组（P<0.05）。
在短暂性全脑缺血再灌注损伤小鼠模型中，抑制泛素化蛋白聚集体可能在异氟烷预处理诱导脑缺血耐受中起关键作用。
