基于突触可塑性和BDNF/TrkB信号通路探讨柴胡-黄芩药对抗抑郁的作用及其机制研究

Depression is a common disorder of mental illness. Anhedonia is the core symptoms of a major depressive disorder, which is closely associated with the dysfunction of the brain reward pathway/circuit. Depression belongs to shaoyang syndrome in syndrome differentiation of six channels theory and thus serial xiaochaihu prescriptions are mainly used for the clinical treatment of depression. According to statistics, the common drug pair of "Bupleurum - skullcap" has the highest frequency in drug pairs of serial chaihu prescriptions. It has been shown in our previous work that to improve the stability of post-synaptic NR2B in the Nucleus Accumbens which plays a key role in reward pathway, can reverse the exacerbation of depressive symptoms and Baicalein, the main monomer ingredient of skullcap, exerts an antidepressant-like effect by regulating the level of BDNF in the brain. Hence, the project aims at studying the effects of "Bupleurum - skullcap", the key drug pair of xiaochaihu decoction which is representative in shaoyang syndrome, on the synaptic plasticity of Nucleus Accumbens and BDNF signaling pathway of reward circuit in chronic social defeat stress mice. By detecting behavior integration, the number of dendritic spines, synaptic density protein, the NAc excitatory postsynaptic potentials and two major signal transduction pathways (PI3K/Akt, ERK) of BDNF/TrkB, screening the optimal ratio of compatibility, concentration and the active time from in vitro and in vivo, the molecular mechanism of antidepressant is explored profoundly, and objective experimental evidence is provided for clinically-safe effective and rational usage of the drug pairs. This also helps to enrich the understanding of the theory of Correspondence of Prescription and Syndrome and Correspondence of drugs and syndromes in TCM

抑郁症是一种常见的情感障碍性精神疾病。快感缺失是其核心症状，主要与大脑奖赏通路（环路）功能异常有关。抑郁症在六经辨证属少阳，多用小柴胡类方治疗，“柴胡-黄芩”药对据统计在柴胡类方中频次最高。前期工作发现，提高奖赏通路关键区域伏隔核突触后膜NR2B的稳定性可逆转抑郁症状；黄芩主要单体成分黄芩素也能通过调节中枢BDNF信号起到抗抑郁效果。因此，本项目旨在研究少阳病代表方小柴胡汤之关键药对柴胡-黄芩，对慢性社会挫败抑郁模型(CSDS)小鼠伏隔核突触可塑性及奖赏通路BDNF/TrkB影响。通过检测行为学、树突棘数目、突触密度蛋白、NAc区兴奋性突触后电位及BDNF/trkB两条主要信号转导通路（PI3K/Akt、ERK），筛选药对的最佳配伍比例、浓度，从整体和离体角度，深入探讨其抗抑郁的分子机制，为临床安全、有效、合理使用该药对提供科学、客观的实验依据。

“柴胡-黄芩”药对多用于抑郁症治疗，其药理机制可能与作用于奖赏环路相关。本课题通过慢性社会挫败抑郁模型(CSDS)和慢性温和不可预知应激抑郁模型（CUMS），通过社会接触、自发活动、糖水消耗、强迫游泳等实验，观察柴胡-黄芩药对抗抑郁的疗效。行为学结果提示，各种浓度和比例的柴胡-黄芩药对均具备一定的抗抑郁作用。课题组通过westernblot对奖赏环路NAc区BDNF、TrkB以及突触可塑性相关蛋白PSD95的表达进行检测。发现低浓度2:1柴胡-黄芩药对降低了NAc区BDNF表达，但TrkB、PSD95的改变各组间差别不显著。根据预实验、行为学结果和BDNF检测结果，课题组选取柴胡黄芩2：1比例，观察奖赏环路NAc区Erk、CREB磷酸化的变化，结果发现高、低剂量组降低Erk磷酸化水平与模型组差异显著，CREB未见磷酸化。与可塑性相关的NR2B在中高剂量组中表达有增加趋势，NR2B上游的CDK5表达有下降趋势。以上结果提示柴胡-黄芩药对2：1可能是最佳配伍比例，其抗抑郁机制涉及到调节Erk磷酸化及通过调节CDK5影响NR2B的表达以调节突触可塑性等。网络药理学挖掘药对作用靶点，发现与五羟色胺受体（HTR2C）阿片受体、糖原合成酶激酶-3β等相关。综合所有结果，本研究为从“药物成分-神经环路-疾病靶点-信号通路”多层面系统探讨柴胡-黄芩药对抗抑郁的作用机制奠定了基础。项目资助发表核心论文2篇，待发表文章1篇。项目投入经费23万元，支出106,374.28元，此外尚有部分劳务费及检测费共计约2.5万元尚未报销，各项支出基本在预算范围内。剩余经费123,625.72元，剩余经费计划用于本项目研究后续支出。