基于小檗碱作为DNA插入子探讨其对正常与缺血再灌神经元基因转录作用差异的机制

Innovative research in this subject is to discuss, using oxygen and glucose deprivation neuronal injury as a carrier, the transcriptional initiation and its law of berberine in the regulation of gene transcription in non-specific inhibition in normal state and in the specificity in the pathological state. Our study showed that berberine can be distributed in the cell, and, as DNA intercalator, can inhibit the transcription of the gene of the normal cells. However, during oxygen and glucose deprivation, berberine can promote cell survival and inhibition of apoptosis-related protein expression, and thus play a protective effect on nerve cells. That is: there is non-specific inhibition of transcription in the normal state and specific transcription start in the pathological state. Such non-specific in the presence of step berberine would exist in specificity. The clarification of this problem will contribute to a fundamental understanding of berberine variety of pharmacological effects, but also helps to recognize of role of berberine and its traditional Chinese medicine Rhizoma coptidis from the perspective of Herbal Nature of Chinese medicine, as well as helps from the molecular biology level to understand and clarify the scientific connotation of the dialectical medication of traditional Chinese medicine.

本课题创新性的研究在于：以缺糖缺氧神经元损伤为载体来探讨小檗碱在基因转录调控时所表现出的非特异抑制与病理状态下特异性转录启动及其规律。我们的研究表明，小檗碱可以分布于细胞内，而其作为DNA插入子，可以抑制正常细胞的基因转录。但是它在缺糖缺氧损伤中可以促进细胞生存和抑制凋亡相关蛋白的高表达、进而对神经细胞起到保护作用。即存在着正常状态下非特异性抑制转录和在病理状态下的特异性转录启动。提示小檗碱的这种非特异性中存在着特异性。对此问题的阐明将有助于从根本上认识小檗碱药理作用的多种性，同时也有助于从中药药性角度认识小檗碱及其中药黄连的作用。有助于从分子生物学层面认识和阐明中药辩证用药的科学内涵。

本工作从实验角度证明了脑缺血再灌损伤过程中对基因转录区甲基化、并由此影响了小檗碱下调基因表达的药理作用。这种甲基化具有缺血缺氧复灌的病理有关，其中与自由基相关。不同的基因，转录启动区的CpG岛的数量是影响其基因转录表达的直接原因。本工作提示生物体内复杂的病理生理变化是影响小檗碱最终药理作用的主要原因，从而提示了机体作用的复杂性。本工作基本阐明了小檗碱药理作用的分子机制，同时也表明了小檗碱在机体内作用的复杂性。对于相关类似物的药物设计、临床上正确使用小檗碱、以及对其药用价值的综合开发提供了实验依据，具有积极的意义。