应用phfMRI研究苍艾挥发油的经鼻脑靶向作用和对抑郁症大鼠脑内单胺类神经递质通路的影响

The study of targeted medicine through the nose-to-brain route is one of the main research directions for central nervous system (CNS) medicines. The complex composition of Chinese medicines and the difficulties of detecting the representative components in vivo makes evaluating the brain targeting of Chinese medicines difficult and constrains the research and development of this therapy. The application of pharmacological functional magnetic resonance imaging (phfMRI) has drawn increasing attention due to its ability for noninvasively evaluating the effects of medicines on the living encephalic regional functions. Previous studies have found that intranasal administration of volatile oil of Cang Ai (VOCA) can significantly improve the activity level of cerebral functions in rats, which suggests that VOCA via intranasal administration has a nose-to-brain route. However, the brain targeting of VOCA requires further study. Moreover, VOCA can improve the activity level of depression related encephalic regional static functions and increase the content of encephalic monoamine neurotransmitters in rats with damaged olfactorius bulb. Therefore, VOCA may have an antidepressant effect. This project will evaluate the brain targeting of VOCA using the technique of phfMRI according to the biological effects method and also establish a preliminary brain-targeting evaluation method for Chinese medicine volatile oil using phfMRI. Furthermore, this project will adopt the chronic stress-induced depression rat model and seed-based correlation analysis method to analyze the effect of VOCA on the degree of correlation among different monoamine neurotransmitter pathways. The neurotransmitter contents and pathways related protein expression will also be tested.The possible mechanism of VOCA’s anti-depressant effect will be investigated at the asholistic level， organ level and molecular level.

经鼻脑靶向药物的研究是CNS药物研究的重要方向。因中药成分复杂、体内检测其代表性成分较难，使脑靶向性评价成为制约中药脑靶向药物研发的主要因素之一。利用phfMRI技术活体无创性评估药物对脑区功能活动的影响逐渐受到关注。前期研究发现苍艾挥发油（VOCA）经鼻给药，可显著提高大鼠脑功能活动水平，提示VOCA鼻腔给药存在鼻-脑通路，但其脑靶向性尚待研究。同时，VOCA能提高嗅球损毁大鼠抑郁相关脑区静态脑功能活动水平，增加脑内单胺递质的含量，因此推测VOCA具潜在抗抑郁活性。本课题拟利用phfMRI技术，按照生物效应法评价药物的脑靶向性，初步建立该技术评估中药挥发油鼻腔给药脑靶向性的方法。此外，拟复制大鼠慢性应激抑郁模型，采用基于种子区的相关分析法分析VOCA对不同单胺类神经递质通路之间相关度的影响，并用递质含量和通路相关蛋白表达加以验证，试从整体、器官和分子水平探讨VOCA治疗抑郁症的可能机制。

苍艾挥发油（VOCA）是由临床效验方提取得到的挥发油复方制剂。前期研究发现，VOCA经鼻给药，可显著提高嗅球损毁大鼠情绪相关脑区静态脑功能活动水平，增加脑内单胺递质的含量，因此推测VOCA具有脑靶向性和潜在抗抑郁活性。本课题利用脑功能核磁共振技术，观察了不同给药方式、不同剂量和给药后不同时间苍艾挥发油对正常大鼠脑区的激活作用，并与薰衣草挥发油和芝麻油做对照，证实了苍艾挥发油经鼻给药具有明确脑靶向性，初步建立应用该技术评估中药挥发油鼻腔给药脑靶向性的方法。为证实其抗抑郁作用和机制，本研究复制了多种行为绝望和抑郁样动物模型，发现VOCA 的能改善模型动物的抑郁样行为。采用fMRI基于种子区的相关分析法分析VOCA对抑郁样大鼠脑内不同单胺类神经递质通路之间的影响，发现VOCA可显著激活DA和5-HT通路。经检测，大鼠脑内DA和5-HT及其代谢产物含量升高，验证了核磁共振的数据结果。此外，蛋白组学研究发现苍艾挥发油发挥抗抑郁的作用还可能与γ-氨基丁酸信号通路、炎症信号通路、线粒体形态和功能调节相关的蛋白有关。进一步研究发现，VOCA可升高大鼠海马GABA和BDNF水平，激活BDNF通路，提高突触前SYP蛋白表达，降低脑促炎细胞因子含量。综上，本项目确证了VOCA的脑靶向性和抗抑郁作用。证实了脑功能核磁共振技术对单胺类神经递质通路功能检测的方法在药物抗抑郁作用机制研究中应用的可行性。同时通过蛋白组学技术揭示了VOCA可能的多环节多靶点的抗抑郁作用机制，并对部分机制进行了验证。本研究利用现代新技术和新方法为中药挥发油复方经鼻给药的抗抑郁作用和机制的研究作出了有益探索。