自噬对血管性痴呆大鼠海马CA1区突触素及突触后膜致密物质95表达的影响

目的 探讨自噬对血管性痴呆大鼠海马CA1区突触素（synaptophysin，Syn）及突触后膜致密物质95（postsynaptic density material 95，PSD-95）表达的影响。方法 健康雄性SD大鼠96只，随机分为假手术组（Sham组）、血管性痴呆模型组（VD组）、自噬抑制剂3-甲基腺嘌呤预处理组（3-MA组）和自噬激动剂雷帕霉素预处理组（Rap组）。每组又分为模型制备成功后1、2、4、8周4个亚组，每个亚组6只大鼠。应用改良的Pulsinelli四血管阻断法制备血管性痴呆模型，采用蛋白质印迹法检测大鼠海马CA1区微管相关蛋白1轻链3（LC3）、Syn、PSD-95蛋白表达。结果（1）与Sham组比较，VD组各时间点LC3-Ⅱ/LC3-Ⅰ比值增加，Syn、PSD-95蛋白表达均减少，差异有统计学意义（P均<0.01）；与VD组比较，3-MA组各时间点LC3-Ⅱ/LC3-Ⅰ比值减少，Syn、PSD-95蛋白表达增加（P<0.05或P<0.01），Rap组各时间点LC3-Ⅱ/LC3-Ⅰ比值增加，Syn、PSD-95蛋白表达降低（P均<0.01）。（2）自噬相关蛋白LC3-Ⅱ/LC3-Ⅰ比值与Syn、PSD-95蛋白表达呈负相关（P均<0.01）。结论 自噬对血管性痴呆大鼠海马CA1区突触可塑性相关蛋白Syn、PSD-95表达具有抑制作用，抑制自噬有利于血管性痴呆大鼠海马CA1区神经突触重塑。
Objective To explore the effect of autophagy on the expression of synaptophysin (Syn) and postsynaptic density material 95 (PSD-95) in CA1 hippocampal region of vascular dementia rats. Methods A total of 96 healthy male SD rats were randomly divided into sham operation group (Sham group), vascular dementia model group (VD group), autophagy inhibitor 3-methyl adenine preconditioning group (3-MA group) and autophagy agonist rapamycin preconditioning group (Rap group). Each group was further randomized into 4 subgroups 1, 2, 4 and 8 weeks after model establishment. The rat model of vascular dementia was established using a modified Pulsinelli four-vessel occlusion method. The expressions of Syn and PSD-95 in CA1 hippocampal region of the vascular dementia rats were detected by Western blotting analysis. Results (1) Compared with the Sham group, the ratio of LC3-Ⅱ/LC3-Ⅰ in CA1 hippocampal region of the vascular dementia rats was significantly increased and the expressions of Syn and PSD-95 were significantly decreased in VD group at different time points (all P<0.01). Compared with the VD group, the ratio of LC3-Ⅱ/LC3-Ⅰ was significantly decreased and the expressions of Syn and PSD-95 were significantly increased in 3-MA group at different time points (P<0.05 or P<0.01); the ratio of LC3-Ⅱ/LC3-Ⅰ was significantly increased and the expression of Syn and PSD-95 were significantly decreased in Rap group at different time points (all P<0.01). (2) Correlation analysis showed that the ratio of LC3-Ⅱ/LC3-Ⅰ was negatively correlated with Syn and PSD-95 expression (all P<0.01). Conclusion Autophagy may inhibit the expression of synaptic plasticity related proteins, Syn and PSD-95, in CA1 hippocampal region of the vascular dementia rats, and suppressing autophagic activity is benefitial to the synaptic plasticity