基因一环境相互作用与男性生殖功能

Gene-environment interaction and male reproductive function

由于遗传因素无法解释短时期内发生的改变，环境和生活方式相关因素被认为是引起与时间相关的男性生殖功能衰退的原因。但是，鉴于不同人群之间以及相同人群内部男性生育力存在很大差别，遗传因素可能极大地影响到人们对环境或生活方式的不利影响的个体易感性。尽管我们对这种和生殖系统相关的相互作用的机制还知之甚少，最近已经有研究表明一些特异的基因型会使得男性在接触某些环境因素后生殖疾病风险大大提高。本文对一些基因如何调节环境对男性生殖功能影响的人类和动物学研究进行了回顾和评论。虽然已经发现一些证据支持这一说法，但是研究数量依然有限。这类基因一环境相互作用的研究可以帮助我们更好地了解正常生理学，并且确定男性生殖疾病的风险因素。我们还简短讨论了与生殖相关的其它基因一环境相互作用方面的话题，即环境和生活方式因素引起精子DNA损伤。这些基因到底改变到什么程度，是通过自然方式，还是辅助生殖技术的应用传给下一代，从而引起子代发病率上升？这些问题还有待于研究探讨。

As genetic factors can hardly explain the changes taking place during short time spans, environmental and lifestyle-related factors have been suggested as the causes of time-related deterioration of male reproductive function. However, considering the strong heterogeneity of male fecundity between and within populations, genetic variants might be important determinants of the individual susceptibility to the adverse effects of environment or lifestyle. Although the possible mechanisms of such interplay in relation to the reproductive system are largely unknown, some recent studies have indicated that specific genotypes may confer a larger risk of male reproductive disorders following certain exposures. This paper presents a critical review of animal and human evidence on how genes may modify environmental effects on male reproductive function. Some examples have been found that support this mechanism, but the number of studies is still limited. This type of interaction studies may improve our understanding of normal physiology and help us to identify the risk factors to male reproductive malfunction. We also shortly discuss other aspects of gene-environment interaction specifically associated with the issue of reproduction, namely environmental and lifestyle factors as the cause of sperm DNA damage. It remains to be investigated to what extent such genetic changes, by natural conception or through the use of assisted reproductive techniques, are transmitted to the next generation, thereby causing increased morbidity in the offspring.