运动预处理对血管性痴呆模型大鼠海马小胶质细胞极化及髓鞘脱失的影响

关键词：血管性痴呆  运动预处理  小胶质细胞极化  髓鞘脱失

Keywords:vascular dementia  exercise preconditioning  microglia polarization  demyelination

摘要：

      摘要 目的：探讨运动预处理对血管性痴呆模型（vascular dementia，VD）大鼠海马小胶质细胞极化及髓鞘脱失的影响。 方法：60只雄性SD大鼠随机分为假手术组、模型组、运动预处理假手术组和运动预处理模型组，每组各15只。运动预处理大鼠在造模前行不负重游泳运动训练4周，每周5次，每次30min。通过双侧颈总动脉结扎法制备VD模型。用Morris水迷宫进行行为学测试，罗克沙尔坚牢蓝染色观察海马CA1区髓鞘脱失情况，免疫荧光双标染色法观察海马CA1区小胶质细胞极化情况，ELISA法检测血清中白细胞介素4（interleukin 4，IL-4）、白细胞介素10（interleukin 10，IL-10）、白细胞介素1β（interleukin-1 beta， IL-1β）、肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）含量。 结果：造模4周后，与假手术组比较，模型组大鼠平均逃避潜伏期延长，穿越平台次数减少（P＜0.05）；与运动预处理假手术组比较，运动预处理模型组大鼠平均逃避潜伏期延长，穿越平台次数减少（P＜0.05）；与运动预处理模型组比较，模型组大鼠逃避潜伏期延长（P＜0.05）。组织学髓鞘脱失评分显示：与假手术组比较，模型组髓鞘脱失增多（P＜0.05）；与运动预处理假手术组比较，运动预处理模型组髓鞘脱失增多（P＜0.05）；与运动预处理模型组比较，模型组大鼠髓鞘脱失增多（P＜0.05）。与假手术组比较，模型组大鼠海马CA1区中诱导型一氧化氮合酶（inducible nitric oxidesynthase，iNOS）蛋白表达增加，精氨酸1（Arginase1，Arg1）蛋白表达减少（P＜0.05）；与运动预处理假手术组比较，运动预处理模型组大鼠海马CA1区中iNOS蛋白表达增加，Arg1蛋白表达减少（P＜0.05）；与运动预处理模型组比较，模型组大鼠大鼠海马CA1区中iNOS蛋白表达显著增加，Arg1蛋白表达显著减少（P＜0.05）；与假手术组比较，模型组大鼠血清中IL-4和IL-10含量降低，IL-1β及TNF-α的含量升高（P＜0.05）；与运动预处理假手术组比较，运动预处理模型组大鼠血清中IL-4和IL-10含量降低，IL-1β及TNF-α的含量明显升高（P＜0.05）；与运动预处理模型组比较，模型组大鼠血清中IL-4含量降低，IL-1β含量升高（P＜0.05）。 结论：运动预处理可促进小胶质细胞M2型极化及髓鞘碎片吞噬，抑制海马神经炎症，改善VD模型大鼠学习记忆能力。

Abstract:

      Abstract Objective： To investigate the effects of exercise preconditioning on hippocampal microglia polarization and myelin loss in vascular dementia（VD） model rats. Method： Sixty male SPF SD rats were randomly divided into sham group， model group， exercise preconditioning sham group and exercise preconditioning model group， with 15 rats in each group. The exercise preconditioning rats was trained in weightless swimming exercise for 4 weeks(5sessions/week, 30min/session) before modeling. The VD model was established by bilateral common carotid artery ligation. Behavioral tests were conducted using the Morris water maze， and the demyelination in the CA1 region of the hippocampus was observed by Luxol fast blue staining. The polarization of microglia in the CA1 region of the hippocampus was observed by immunofluorescence double labeling staining， and the contents of interleukin 4 （IL-4）， interleukin 10 （IL-10）， interleukin-1 beta （IL-1β）， and tumor necrosis factor-α （TNF-α） in the serum were detected by ELISA. Result：Four weeks after modeling， the average escape latency of rats in the model group was prolonged and the number of platform crossings was reduced compared with the sham group（P<0.05）；the average escape latency of rats in the exercise preconditioning model group was prolonged and the number of platform crossings was reduced compared with the exercise preconditioning sham group（P<0.05）；the escape latency of rats in the model group was prolonged compared with the exercise preconditioning model group（P<0.05）. The histological demyelination score showed that compared with the sham group， the demyelination in the model group was increased（P<0.05）；the demyelination in the exercise preconditioning model group was increased compared with the exercise preconditioning sham group（P<0.05）；the demyelination in the model group was increased compared with the exercise preconditioning model group（P<0.05）. Compared with the sham group， the expression of inducible nitric oxide synthase（iNOS） protein in the CA1 region of the hippocampus in the model group was increased，while the expression of arginase1（Arg1） protein was decreased（P<0.05）. Compared with the exercise preconditioning sham group， the expression of iNOS protein in the CA1 region of the hippocampus in the exercise preconditioning model group was significantly increased（P<0.05），while the expression of Arg-1 protein was significantly decreased（P<0.05）. Compared with the exercise preconditioning model group，the expression of iNOS protein in the CA1 region of the hippocampus in the model group was increased， while the expression of Arg1 protein was decreased（P<0.05）. Compared with the sham group，the contents of IL-4 and IL-10 in the serum of rats in the model group decreased，while the contents of IL-1β and TNF-α increased（P<0.05）. Compared with the exercise preconditioning sham group， the contents of IL-4 and IL-10 in the serum of rats in the exercise preconditioning model group decreased， while the contents of IL-1β and TNF-α increased（P<0.05）. Compared with the exercise preconditioning model group， the content of IL-4 in the serum of rats in the model group decreased， while the content of IL-1β increased（P<0.05）. Conclusion： Exercise preconditioning can promote microglial M2 polarization and myelin fragment phagocytosis， inhibit hippocampal nerve inflammation， and improve the learning and memory ability of rats with vascular dementia.