SLC6A4基因在5-HT系统调控射精功能中的作用及机制研究

Premature ejaculation (PE) is one of the most common sexual dysfunctions among men. However，the etiology and pathogenesis of PE are still unknown. Plenty of researches have found that 5-hydroxytryptamine(5-HT) might play a vital role in the pathogenesis of PE. And we have found that 5-HT transporter(5-HTT) encoded by gene SLC6A4 was significantly correlated with PE in our previous researches. To explore the relationship between SLC6A4 and PE further, and the mechanism of SLC6A4 in the ejaculatory regulating, the SLC6A4-knockout rats models will be prepared to investigate the changes of ejaculation at individual level. And the differences of SLC6A4 mapping in the spinal cord and brain between the knockout rats and normal ones will be investigated at organizational level. The polymorphism is an important way of the disease linked to gene, so we will screen the different loci of SLC6A4 in Han Chinese with or without PE. Then we will verify the loci in a large sample case-control study. Finally, we will explore the effects of different gene polymorphism on the expression of 5-HTT at cellular level by in vitro experiments. The results will help to find the mechanism of SLC6A4 in the ejaculatory regulating, and provide a new theoretical basis for the gene diagnosis and individualized treatment for PE.

早泄是男性最常见的性功能障碍疾病，其病因和发病机制尚不明确。国内外研究均显示神经递质5-羟色胺（5-HT）在射精调控中起重要作用，我们的初步研究发现，调控5-HT水平的5-HT转运体（5-HTT）编码基因SLC6A4与早泄的发病可能存在相关性。为了进一步明确SLC6A4在5-HT系统调控射精功能中的作用及机制，本课题拟在已有研究基础上，构建SLC6A4敲除动物模型，从个体水平探讨SLC6A4敲除大鼠射精功能的改变情况，再从组织水平探讨SLC6A4敲除鼠与对照鼠5-HTT在脊髓和大脑的定位及定量表达差异。由于多态性是基因致病的重要途径，我们拟筛选早泄患者与正常对照SLC6A4的差异性多态位点，并利用大样本病例对照实验确定易感多态性位点。最后通过细胞转染从细胞水平探索SLC6A4多态性对5-HTT表达的影响，进而阐明SLC6A4参与射精调控的可能机制，为早泄的基因诊断和个体化治疗提供理论依据。

早泄（premature ejaculation, PE）是男性最常见的性功能障碍疾病之一，发病机制尚不明确。研究表明5-羟色胺（5-hydroxytryptamine, 5-HT）在射精调控中起重要作用，调控5-HT水平的5-HT转运体（5-HT transporter, 5-HTT）编码基因SLC6A4与PE的发病可能存在相关性。本研究在此基础上，收集PE患者和健康对照血标本，构建SLC6A4敲除动物模型，通过基因芯片、生物信息学方法、免疫印迹实验、报告基因实验、实时定量PCR技术、免疫组化等，从临床上探索PE与SLC6A4基因多态性、慢性前列腺炎、勃起功能障碍等相关性，从个体水平探索基因敲除大鼠射精功能的变化，从组织水平探索敲除大鼠5-HTT在脊髓和大脑的定位及定量表达变化。结果发现：SLC6A4基因启动子区域多态性LA等位基因可能是PE的保护性位点，第二个内含子重复序列STin2.12/12可能是PE的易感位点，S等位基因和STin2.10等位基因可能在不射精患者中出现频率高；色氨酸羟化酶-2（Tryptophan hydroxylase 2，TPH2）基因上的SNV019和rs4290270多态性可能与LPE有一定的相关性；基因敲除纯合型大鼠相关射精控制脑区中的5-HT 水平显著升高，最终导致射精延迟、射精次数减少，而杂合型大鼠脑组织5-HT水平虽下降50%左右，但其行为未发生明显变化；射精过快大鼠脑组织TPH2、脑源性神经营养因子（Brain-derived neurotrophic factor, BDNF）水平下降，S100B蛋白、神经元特异性烯醇化酶（Neuron-specific enolase, NSE)水平升高，外周血BDNF、S100B、NSE水平变化与脑组织水平变化趋势一致，这表明TPH2、BDNF、S100B、NSE可能参与了射精的调控；流行病学资料显示PE患者国际勃起功能指数-15评分偏低、前列腺炎症状指数评分升高，提示PE与勃起功能障碍、慢性前列腺炎有一定相关性。对PE发病机制的深入研究，有助于对PE的临床诊断和个体化治疗提供理论依据。相关研究成果已发表论文14篇（SCI论文8篇，中文期刊论文6篇），待发表SCI论文3篇，其他数据正在整理和撰写中。且多次参加国内外学术交流，促进科研成果的传播，取得了良好的成效。