Kuang Guiying, Shu Zhigang, Zhu Chunli, Li Hongbing, Zhang Cheng
Neurological Department, Wuhan Red Cross Hospital, Wuhan, Hubei Province, 436015, China.
Neurological Department, Ezhou Central Hospital, Ezhou, Hubei Province, 436000, China.
Transl Neurosci. 2023 Aug 23;14(1):20220302. doi: 10.1515/tnsci-2022-0302. eCollection 2023 Jan 1.
The objective of this study was to investigate the effect of modified Dioscorea pills (MDP) on microcirculatory remodeling in the hippocampus of rats with chronic cerebral hypoperfusion (CCH) through the angiopoietin (Ang)/tyrosine kinase receptor tyrosine kinase with immunoglobulin-like and EGF-like domains (Ang receptor) 2 (Tie-2) signaling pathways, which may underlie the cognitive improvement observed in CCH rats.
Forty male Sprague-Dawley rats raised under specific pathogen-free conditions were randomly divided into three groups: control group (10 rats), model group (15 rats), and MDP group (15 rats). The rats in the model group and MDP group underwent bilateral common carotid artery occlusion using the 2-vessel occlusion (2-VO) method to induce CCH. Rats in the control group underwent the same surgical procedures as those in the model group, except for ligation and occlusion of the carotid arteries. After 1 week of 2-VO, rats in the MDP group were administered MDP condensed decoction intragastrically at a dose of 1 ml/100 g body weight (prepared by the Preparation Room of Hubei Provincial Hospital of Traditional Chinese Medicine) for 45 days, while rats in the other two groups received normal saline intragastrically with the same dose and duration as the MDP group. After the intervention, all rats were euthanized, and brain perfusion was performed to obtain the hippocampal tissue for analysis. Immunohistochemical staining for CD43 was performed to assess microvessel density (MVD); western blot and the reverse transcription-polymerase chain reaction (RT-PCR) were used to analyze the expression of proteins and genes in angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), Tie-2, and vascular endothelial growth factor (VEGF) proteins and genes in the hippocampal tissue and compute the Ang-1/Ang-2 ratio.
MDP treatment reduced neuronal loss and promoted restoration of the damaged hippocampal structure in CCH rats. The model group showed significantly higher MVD (14.93 ± 1.92) compared to the control group (5.78 ± 1.65) ( < 0.01), whereas MDP treatment further increased MVD (21.19 ± 2.62). Western blot and RT-PCR analysis revealed that CCH significantly increased the expression of Ang-1, Ang-2, Tie-2, and VEGF proteins and genes, while MDP treatment further significantly upregulated the expression of these proteins and genes. In addition, MDP significantly elevated the gene and protein expression of the Ang-1/Ang-2 ratio compared to the control group ( = 0.041, = 0.029).
CCH induces microvascular neogenesis in the hippocampus, and MDP promotes angiogenesis and microcirculation remodeling in CCH rats via the Ang/Tie signaling pathway, which may be an important mechanism for its restorative effects on hippocampal perfusion and improvement of cognitive function in CCH rats.
本研究旨在通过血管生成素（Ang）/含免疫球蛋白样和表皮生长因子样结构域的酪氨酸激酶受体（Ang受体）2（Tie-2）信号通路，探讨改良山药丸（MDP）对慢性脑灌注不足（CCH）大鼠海马微循环重塑的影响，这可能是CCH大鼠认知功能改善的潜在机制。
将40只在无特定病原体条件下饲养的雄性Sprague-Dawley大鼠随机分为三组：对照组（10只大鼠）、模型组（15只大鼠）和MDP组（15只大鼠）。模型组和MDP组大鼠采用双动脉结扎法（2-VO）进行双侧颈总动脉闭塞以诱导CCH。对照组大鼠接受与模型组相同的手术操作，但不结扎和闭塞颈动脉。2-VO术后1周，MDP组大鼠以1 ml/100 g体重的剂量灌胃给予MDP浓缩煎剂（由湖北省中医院制剂室制备），持续45天，而其他两组大鼠以与MDP组相同的剂量和持续时间灌胃给予生理盐水。干预后，所有大鼠均安乐死，进行脑灌注以获取海马组织进行分析。采用CD43免疫组织化学染色评估微血管密度（MVD）；采用蛋白质印迹法和逆转录聚合酶链反应（RT-PCR）分析海马组织中血管生成素-1（Ang-1）、血管生成素-2（Ang-2）、Tie-2和血管内皮生长因子（VEGF）蛋白及基因的表达，并计算Ang-1/Ang-2比值。
MDP治疗可减少CCH大鼠的神经元损失，并促进受损海马结构的恢复。模型组的MVD（14.93±1.92）显著高于对照组（5.78±1.65）（P<0.01），而MDP治疗进一步增加了MVD（21.19±2.62）。蛋白质印迹法和RT-PCR分析显示，CCH显著增加了Ang-1、Ang-2、Tie-2和VEGF蛋白及基因的表达，而MDP治疗进一步显著上调了这些蛋白及基因的表达。此外，与对照组相比，MDP显著提高了Ang-1/Ang-2比值的基因和蛋白表达（P=0.041，P=0.029）。
CCH可诱导海马微血管新生，MDP通过Ang/Tie信号通路促进CCH大鼠的血管生成和微循环重塑，这可能是其对CCH大鼠海马灌注恢复和认知功能改善的重要机制。
