抑郁症肝郁致脾虚的中枢海马—下丘脑调控机制研究

Basic research on traditional Chinese medicine prescription cannot be separated from syndrome, which has less toxicity and side effect compared with chemical medicine for depression. Preliminary studies indicate that stagnation of liver and spleen deficiency syndrome is the main syndrome of depression. Our previous experimental study has established and successfully replicated a stable depression stagnation of liver depression and spleen deficiency rat "three-dimensional" model with macro characterization and behavior tests, microscopic physicochemical indexes, and prescription disproof, which showed that liver stagnation syndrome can develop into liver stagnation and spleen deficiency. Considering our basic work on rats function NMR BOLD and serum biochemical index test results of depression rats with stagnation of liver stagnation and spleen deficiency syndrome, we presume that in depression rats with liver stagnation syndrome caused by chronic stress, their CRH - ACTH - CORT pathway activity lead to hippocampal neuronal damage, resulting in changes of some receptors or neurotransmitters, which in turn acts in the hypothalamus to further increase the CRH - ACTH - CORT pathway, forming a positive feedback effect, which become the causes of liver stagnation and spleen deficiency syndrome. Our research group intends to use dynamic grouping method, using molecular biology, digital gene expression profile sequencing and bioinformatics mining technology to get involved in the regulation molecular of this positive feedback effect, and initially reveal the biological mechanism of depression development from liver stagnation to spleen deficiency syndrome, which help to explore new regulatory mechanism of hippocampus.

治疗抑郁症的化学药物毒副作用大，而中药方剂的基础研究离不开中医证候的研究。前期文献研究表明，肝郁证和脾虚证为抑郁症的主要证候。前期实验研究中，课题组通过宏观表征和行为学试验、微观理化指标、方剂反证“三维”建立了稳定的抑郁症肝郁证和肝郁脾虚证大鼠模型并且成功复制，发现肝郁证可以演变为肝郁脾虚证，并结合抑郁症肝郁证和肝郁脾虚证大鼠功能核磁BOLD和血清理化指标检测结果等工作基础，推测慢性应激造成抑郁症肝郁证时CRH—ACTH—CORT通路异常活跃导致海马神经元损伤，使某些受体或神经递质改变，反过来又作用于下丘脑使其进一步上调了CRH—ACTH—CORT通路，形成了持续放大的正反馈效应，导致了肝郁脾虚证的发生。课题组拟采用动态分组的方法，利用分子生物学、数字化基因表达谱测序和生物信息学等技术挖掘参与调控这一正反馈效应的分子，初步揭示抑郁症肝郁致脾虚的生物学机制，这有助于探索海马新的调控机制。

本课题通过宏观表征和行为学、微观理化指标、方剂反证“三维”建立了稳定的抑郁症肝郁证和肝郁脾虚证大鼠模型，抑郁症大鼠肝郁证稳定的证候时间窗为应激4周时，抑郁症大鼠肝郁脾虚证稳定的证候时间窗为应激8周时。课题组对抑郁症肝郁证和肝郁脾虚证两种病证结合大鼠进行了脑功能核磁（fMRI）检测，发现肝郁脾虚证大鼠大脑海马和下丘脑脑区功能相对于抑郁症肝郁证大鼠和正常大鼠明显减弱。因此，课题组对海马和下丘脑进行了有参转录组测序对比分析，发现海马有8个、下丘脑有112个与消化相关（纳呆、便溏等症状）的差异表达基因，通过GO富集和KEGG富集以及蛋白互作网络分析，得出主要差异基因集中在HPA轴CRH-ACTH-CORT通路上，该通路位于下丘脑，抑郁症肝郁证时该通路异常激活，肝郁脾虚证时极度异常激活，表现在CRH和CORT含量显著升高，从而使海马HMDA受体过度激活，海马神经元细胞膜表面Ca2+通道开放，大量Ca2+内流，使海马神经元损伤，神经递质5-HT水平急剧降低，使得外周（肠）5-HT水平急剧升高，5-HT 在胃肠道通过作用于不同受体来调节胃肠道的运动，其中包括同时作用于肠平滑肌上的5-HT2A（收缩作用）、5- HT4和5-HT7（舒张作用）受体，使肠道痉挛，出现便溏等脾虚证症状。.同时，课题组发现肝郁脾虚证大鼠肝总动脉血流量和收缩期血流速度明显低于肝气郁结证组，而肝气郁结证组与正常组相比无显著差异。课题组认为肝郁证大鼠出现脾虚证症状时，肝血流发生变化，意味着全身的血液分布可能出现了异常，课题组随即对脑动脉血流进行了检测，发现肝郁脾虚证组大脑前动脉充盈量低于肝气郁结证组，而大脑中动脉和后动脉充盈量高于肝气郁结证组，这说明抑郁症肝郁致脾虚存在外周调控机制，且与“肝藏血”储藏血液调节血量功能异常有关。课题组对肠循环的血液灌注情况尚未做研究，因此，对于肝郁致脾虚的外周生物学机制有待于深入的研究。