氚β粒子照射对发育中的中枢神经系统的影响及机制研究

Effects of tritium beta particles on the developing central nervous system and the underlying mechanisms

电离辐射对发育中的中枢神经系统的影响及其机制的研究是国际放射防护委员会和联合国原子辐射效应科学委员会的重要课题。对原子弹爆炸幸存者进行流行病学调查研究的结果是目前评价辐射对人类脑发育和神经行为危险度的主要依据。这些结果是基于对一次性短时间内高剂量率辐射所产生的影响的总结, 并不能准确反映氚β粒子在连续长时间内低剂量率辐射情况下所产生的生物效应。特别是中枢神经系统的辐射敏感性随着其发育阶段而变化, 这就造成了在不同的照射情况下所产生的辐射危险度的不同。笔者以原卫生部工业卫生实验所(现中国疾病预防控制中心辐射防护与核安全医学所)周湘艳的氚生物效应研究团队从二十世纪八十年代至今的研究成果为主线, 概述了中国研究人员在低剂量氚辐射对发育中的中枢神经系统的影响及其机制领域开展的一系列综合系统的研究中所取得的重要成果。研究者对仔鼠的生长发育、神经行为学、脑组织病理学、脑组织神经生物化学、初代培养大鼠大脑组织细胞电生理学和初代培养小鼠中脑细胞形态学和生物化学的变化等方面, 使用了总计56项生物学终点作为评价指标, 从多层次综合地探讨了低剂量氚β粒子子宫内照射对发育中的中枢神经系统的影响及其机制。该研究在世界上是第一次在同一系列实验系统中, 从分子、细胞、器官到整体, 从组织结构、神经生化、行为到学习记忆功能, 从动物的个体到细胞的离体培养, 综合评价了低剂量氚β粒子连续照射对发育中的中枢神经系统的危险度。这些重要的研究成果为全面系统地评价氚β粒子辐射的危险度提供了具有可信度和权威性的科学依据。

The study of the effects of ionizing radiation on the developing central nervous system and the underlying mechanisms is an important subject for the International Commission on Radiological Protection and United Nations Scientific Committee on the Effects of Atomic Radiation.Results from epidemiological investigations on A-bomb survivors are the main basis for evaluating radiation risk.However,given that these results reflect the biological effects of high-dose-rate single acute exposure,they cannot accurately reflect the biological effects of tritium beta particles under low-dose-rate continuous exposure.Radiation sensitivity of the central nervous system changes with its developmental stage,resulting in different radiation risks under various exposure situations.This paper reviews the achievements obtained in a series of comprehensive studies led by Dr.Zhou's research group of the former Laboratory of Industrial Hygiene,Ministry of Public Health(now National Institute for Radiological Protection,Chinese Center for Disease Control and Prevention)from the 1980s to the present.Researchers used a total of 56 biological endpoints as evaluation indicators for physiological development,neurobehavior,brain pathology,and neurobiochemistry in prenatally exposed offspring,as well as electrophysiology,morphological,and biochemical changes in brain cells in primary cultures,comprehensively explored the effects and mechanisms of low-dose tritiumβparticles intrauterine irradiation on the developing central nervous system from multiple levels.This work is the first time to use the same experimental systems,from molecules,cells,and organs to the whole body,from tissue structure,neurobiochemistry,and behavior to learning and memory functions,to evaluate the risk of continuous low-dose tritium beta particle exposure on the developing central nervous system.These important achievements provide the most reliable and authoritative scientific basis for comprehensively and systematically evaluating the radiation risk of tritium beta particles on the developing central nervous system.