AMPK/mTOR信号通路介导的细胞自噬在电磁辐射致精细胞DNA损伤中的作用及其机制研究

Electromagnetic radiation (EMR) induced impairments of male reproductive system, while the mechanism underlying impairments of male reproductive system is not very clear. Our previous studies about germ cells of male mice which was exposed by EMR, showed that the level of reactive oxygen species (ROS) was increased, DNA was damaged and the level of autophagy was decreased. It was reported that cell autophagy could maintain the normal function of cells by clearance the redundant ROS and damaged DNA, and promotion to repair the damaged DNA. Thus, it was speculated that the EMR exposure may induce DNA damaged by decreasing the elimination level of autophagy. This study will analyze the effects of EMR exposure on the germ cell autophagy, and through inhibition and promotion of autophagy in the germ cells to identify the function of autophagy on the EMR induced DNA damage. Due to the importance of AMPK/ mTOR signal pathway in the autophagy, the effects of EMR exposure on the related genes with AMPK/mTOR signal pathway was detected, and the expression of AMPK was regulated to reveal the mechanism of EMR induced the change of autophagy. It is expected that our study will provide a new target to medical safe guard underlying the EMR-induced impairments the function of reproductive system.

电磁辐射可引起雄性生殖功能的损伤，但其损伤的机制尚不清楚。本项目组前期研究发现，电磁辐射可以引起精细胞DNA损伤，活性氧自由基(ROS)产生增加，并引起自噬发生水平降低。报道显示，细胞自噬能够清除细胞内多余的ROS及受损DNA，并能促进DNA损伤后修复，维持细胞内正常功能。据此推测：电磁辐射可能通过诱导自噬清除障碍，进而促进精细胞DNA损伤。本项目拟通过定性定量分析电磁辐射对精细胞自噬的影响，并通过抑制和促进自噬发生，明确自噬在电磁辐射致精细胞DNA损伤中的作用；基于AMPK/mTOR信号通路在自噬发生中的重要性，检测电磁辐射对精细胞AMPK/mTOR信号通路相关基因表达的影响，并通过干预AMPK的表达，揭示电磁辐射致精细胞自噬水平变化的分子机制。通过本研究，有望为电磁辐射致雄性生殖功能损伤的医学防护提供新的靶点和依据。

雄性生殖系统对电磁辐射具有高度的敏感性。电磁辐射能使机体发生氧化应激及能量代谢异常，致使睾丸结构和功能损伤，精子质量下降，睾酮水平显著降低等。电磁辐射引起精细胞DNA损伤，可能是电磁辐射致雄性生殖功能紊乱的重要机制之一。而细胞自噬能够清除受损的DNA，并激活DNA损伤后修复的信号通路，有助于维持DNA完整性，是DNA损伤后细胞内发生的一种保护性反应。明确自噬在电磁辐射致精细胞DNA损伤中的作用，以及电磁辐射诱导自噬水平降低的机制，开展这部分工作对阐明电磁辐射引起生殖功能障碍的原因具有重要意义。.本研究建立了电磁辐射导致精细胞DNA损伤的稳定细胞模型。我们的实验体系中，通过电磁辐射1800MHz（1, 2, 4 W/kg）辐射小鼠精母细胞GC-2 24hr，结果显示，4 W/kg电磁辐射1800MHz不仅能够导致精细胞存活率下降、DNA单链损伤和ROS水平增加，而且还能够导致精细胞自噬水平升高。我们进而利用westernblot方法检测精细胞经电磁辐射（4 W/kg）暴露24hr后，自噬信号通路AMPK/mTOR的蛋白磷酸化水平，并通过干扰和过表达AMPK，抑制或促进自噬发生，检测电磁辐射对精细胞DNA损伤的影响。结果显示，干扰AMPK后，小鼠精母细胞经电磁辐射1800MHz（4 W/kg）辐射24hr，自噬水平显著降低，DNA损伤水平明显升高。当抑制AMPK表达后，小鼠精母细胞经电磁辐射1800MHz（4 W/kg）辐射24hr，自噬水平显著升高，DNA损伤水平明显降低。结果表明，自噬在电磁辐射致精细胞DNA损伤中，通过AMPK/mTOR信号通路发挥保护作用。