Objective 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. Methods 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. Results 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) (P < 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 (P = 0.041, P = 0.029). Conclusion 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.

中文翻译：

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改良薯蓣丸通过 Ang/Tie 信号通路对慢性脑灌注不足血管重塑的促进作用。

目的探讨改良薯蓣丸（MDP）通过血管生成素（Ang）/酪氨酸激酶受体酪氨酸激酶与免疫球蛋白样和免疫球蛋白样受体结合对慢性脑低灌注（CCH）大鼠海马微循环重塑的影响。 EGF 样结构域（Ang 受体）2 (Tie-2) 信号通路，可能是在 CCH 大鼠中观察到的认知改善的基础。方法将40只雄性Sprague-Dawley大鼠随机分为3组：对照组（10只）、模型组（15只）和MDP组（15只）。模型组和MDP组大鼠采用双血管闭塞(2-VO)法双侧颈总动脉闭塞诱导CCH。对照组大鼠除颈动脉结扎、闭塞外，手术操作与模型组相同。2-VO 1周后，MDP组大鼠按1 ml/100 g体重（湖北省中医院制剂室配制）灌胃MDP浓缩汤，连续45 d。另两组大鼠灌胃生理盐水，剂量和持续时间与MDP组相同。干预后，将所有大鼠安乐死，并进行脑灌注，获取海马组织进行分析。对 CD43 进行免疫组织化学染色以评估微血管密度 (MVD)；采用蛋白质印迹和逆转录聚合酶链反应（RT-PCR）分析血管生成素-1（Ang-1）、血管生成素-2（Ang-2）、Tie-2和血管中蛋白质和基因的表达。海马组织中的内皮生长因子 (VEGF) 蛋白和基因并计算 Ang-1/Ang-2 比率。结果 MDP 治疗减少了 CCH 大鼠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）显着高于对照组（5.78±1.65）（P < 0.01），而MDP治疗进一步增加了MVD（21.19±2.62）。Western blot和RT-PCR分析显示，CCH显着增加了Ang-1、Ang-2、Tie-2和VEGF蛋白和基因的表达，而MDP处理进一步显着上调了这些蛋白和基因的表达。此外，与对照组相比，MDP显着升高了Ang-1/Ang-2比值的基因和蛋白表达（P = 0.041，P = 0.029）。结论 CCH诱导海马微血管新生，MDP通过Ang/Tie信号通路促进CCH大鼠血管新生和微循环重塑，这可能是其恢复CCH大鼠海马血流灌注、改善认知功能的重要机制。