Department of Physiology, Basic Medical College of Beihua University, Jilin 132013, China.
Nursing College of Beihua University, Jilin 132013, China.
Biomed Res Int. 2017;2017:3214918. doi: 10.1155/2017/3214918. Epub 2017 Nov 28.
The hippocampus is a key structure for encoding and processing memory and for spatial orientation, which are among the cognitive functions most sensitive to cerebral ischemia, hypoxia, and vascular dementia (VD). Since hippocampal formation is one of the principle forebrain targets for arginine-vasopressin (AVP) innervations arising in the hypothalamic paraventricular nucleus (PVN), we explored the contributions of AVP to VD pathogenesis. To this end, we randomly assigned pathogen-free, male Wistar rats to one of seven groups in a VD model and tested AVP treatment effects on spatial learning and memory using the Morris water maze. We also measured the superoxide dismutase (SOD) activity and malondialdehyde (MDA) concentration in brain samples and monitored the expression of AVP-positive neurons in the hippocampus by immunohistochemistry. The VD model with repeated cerebral ischemia-reperfusion injury evoked impairment of cognitive function and reduced cerebral concentrations of the antioxidation markers. Lesioning the rat PVN showed a similar effect on learning and memory and reduced antioxidation markers in the brain tissue. However, AVP injection into the PVN improved cognitive performance in VD rats, while enhancing/rectifying the changes in antioxidation markers. We conclude that our VD model may decrease AVP secretion in the PVN and subsequently reduce antioxidant capacity in the hippocampus, leading to impaired cognitive function.
海马体是编码和处理记忆以及空间定向的关键结构，而这些认知功能对脑缺血、缺氧和血管性痴呆（VD）最为敏感。由于海马结构是下丘脑室旁核（PVN）发出的精氨酸加压素（AVP）神经支配的主要前脑靶标之一，我们探讨了 AVP 对 VD 发病机制的贡献。为此，我们将无病原体的雄性 Wistar 大鼠随机分配到 VD 模型的七个组中的一个，并使用 Morris 水迷宫测试 AVP 治疗对空间学习和记忆的影响。我们还测量了脑样本中超氧化物歧化酶（SOD）活性和丙二醛（MDA）浓度，并通过免疫组织化学监测海马中 AVP 阳性神经元的表达。反复脑缺血再灌注损伤引起的 VD 模型引起认知功能障碍，并降低了大脑中抗氧化标志物的浓度。损伤大鼠的 PVN 显示出对学习和记忆的类似影响，并降低了脑组织中的抗氧化标志物。然而，AVP 注射到 PVN 中可改善 VD 大鼠的认知表现，同时增强/纠正抗氧化标志物的变化。我们得出结论，我们的 VD 模型可能会降低 PVN 中的 AVP 分泌，从而降低海马中的抗氧化能力，导致认知功能障碍。
