饮食对精子质量有快速影响 Diet has rapid effects on sperm quality

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精子受饮食影响,其作用迅速出现。这是林雪平大学研究人员的一项研究的结论,在该研究中,健康的年轻人接受了富含糖分的饮食。该研究已经发表在《 PLOS Biology》上,它对精子的功能提供了新的见解,并且从长远来看可能会为测量精子质量的新诊断方法做出贡献。

饮食部高级讲师安妮塔·奥斯特(AnitaÖst)表示:“我们发现饮食会影响精子的活力,我们可以将这些变化与精子中的特定分子联系起来。我们的研究表明,这种快速反应在一到两周后就很明显了。”林雪平大学的临床和实验医学,研究负责人。

精子质量可能受到多种环境和生活方式因素的损害,其中肥胖和相关疾病(例如2型糖尿病)是精子质量差的众所周知的危险因素。进行这项新研究的研究小组对表观遗传现象感兴趣,这些现象涉及物理特性或基因表达水平的变化,即使遗传物质,DNA序列没有变化也是如此。在某些情况下,这种表观遗传变化可能导致特性通过精子或卵从父母亲传给后代。

在先前的研究中,科学家们发现雄性果蝇在交配之前不久就消耗了过多的糖,而这种果蝇更经常繁殖而产生超重的后代。对小鼠的类似研究表明,称为tsRNA的RNA小片段在下一代出现的这些表观遗传现象中起作用。这些RNA片段大量存在于许多物种(包括人,果蝇和小鼠)的精子中。到目前为止,尚未对其功能进行详细检查。科学家推测,精子中的RNA片段可能与表观遗传现象有关,但现在说人类是否如此尚为时过早。这项新研究是由研究人员发起的,旨在研究高糖摄入是否会影响人类精子中的RNA片段。

这项研究检查了15名正常的,不吸烟的年轻人,他们按照饮食进行了为期两周的科学家饮食。饮食基于北欧人健康饮食的营养建议,但有一个例外:研究人员在第二周内每天添加糖,相当于约3.5升碳酸饮料或450克糖果。在研究开始时,第一周之后(他们饮食健康)和第二周之后(参与者另外消耗了大量糖分),对参与者的精子质量和其他健康指标进行了调查。 )。

在研究开始时,三分之一的参与者精子活力低。运动能力是影响精子质量的几个因素之一,本研究中精子运动能力低的人群与普通人群的比例相对应。研究人员惊讶地发现所有参与者的精子运动在研究过程中都恢复正常。

“这项研究表明,精子活力可以在短时间内改变,并且似乎与饮食密切相关。这具有重要的临床意义。但是我们不能说是否是糖引起了这种作用,因为它可能是基本健康饮食中对精子有积极作用的一种成分”,AnitaÖst说。

研究人员还发现,与精子活力有关的小RNA片段也发生了变化。他们现在计划继续进行这项工作,并调查男性生殖力和精子中RNA片段之间是否存在联系。他们还将确定RNA代码是否可用于新的诊断方法,以在体外受精过程中测量精子质量。

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News Release 

Diet has rapid effects on sperm quality

Linköping University

IMAGE
IMAGE: This is Anita Öst, senior lecturer at Linköping University. view more 

Credit: Ulrik Svedin/LiU

Sperm are influenced by diet, and the effects arise rapidly. This is the conclusion of a study by researchers at Linköping University, in which healthy young men were fed a diet rich in sugar. The study, which has been published in PLOS Biology, gives new insight into the function of sperm, and may in the long term contribute to new diagnostic methods to measure sperm quality.

“We see that diet influences the motility of the sperm, and we can link the changes to specific molecules in them. Our study has revealed rapid effects that are noticeable after one to two weeks”, says Anita Öst, senior lecturer in the Department of Clinical and Experimental Medicine at Linköping University, and head of the study.

Sperm quality can be harmed by several environmental and lifestyle factors, of which obesity and related diseases, such as type 2 diabetes, are well-known risk factors for poor sperm quality. The research group that carried out the new study is interested in epigenetic phenomena, which involve physical properties or levels of gene expression changing, even when the genetic material, the DNA sequence, is not changed. In certain cases such epigenetic changes can lead to properties being transferred from a parent to offspring via the sperm or the egg.

In a previous study, the scientists showed that male fruit flies which had consumed excess sugar shortly before mating more often produced offspring who became overweight. Similar studies on mice have suggested that small fragments of RNA known as tsRNA play a role in these epigenetic phenomena that appear in the next generation. These RNA fragments are present in unusually large amounts in the sperm of many species, including humans, fruit flies and mice. So far, their function has not been examined in detail. Scientists have speculated that the RNA fragments in sperm may be involved in epigenetic phenomena, but it is too early to say whether this is the case in humans. The new study was initiated by the researchers to investigate whether a high consumption of sugar affects the RNA fragments in human sperm.

The study examined 15 normal, non-smoking young men, who followed a diet in which they were given all food from the scientists for two weeks. The diet was based on the Nordic Nutrition Recommendations for healthy eating with one exception: during the second week the researchers added sugar, corresponding to around 3.5 litres of fizzy drinks, or 450 grammes of confectionery, every day. The sperm quality and other indicators of the participants’ health were investigated at the start of the study, after the first week (during which they ate a healthy diet), and after the second week (when the participants had additionally consumed large amounts of sugar).

At the beginning of the study, one third of the participants had low sperm motility. Motility is one of several factors that influence sperm quality, and the fraction of people with low sperm motility in the study corresponded to that in the general population. The researchers were surprised to discover that the sperm motility of all participants became normal during the study.

“The study shows that sperm motility can be changed in a short period, and seems to be closely coupled to diet. This has important clinical implications. But we can’t say whether it was the sugar that caused the effect, since it may be a component of the basic healthly diet that has a positive effect on the sperm”, says Anita Öst.

The researchers also found that the small RNA fragments, which are linked to sperm motility, also changed. They are now planning to continue the work and investigate whether there is a link between male fertility and the RNA fragments in sperm. They will also determine whether the RNA code can be used for new diagnostic methods to measure sperm quality during in vitro fertilisation.

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The study has been carried out in collaboration with the Reproductive Medicine Center at Linköping University Hospital, with financial support from the Swedish Research Council, the Knut and Alice Wallenberg Foundation, and the Ragnar Söderberg Foundation.

The article: “Human Sperm Displays Rapid Responses to Diet”, Daniel Nätt, Unn Kugelberg, Eduard Casas, Elizabeth Nedstrand, Stefan Zalavary, Pontus Henriksson, Carola Nijm, Julia Jäderquist, Johanna Sandborg, Eva Flinke, Rashmi Ramesh, Lovisa Örkenby, Filip Appelkvist, Thomas Lingg, Nicola Guzzi, Cristian Bellodi, Marie Löf, Tanya Vavouri, Anita Öst, PLOS Biology, published online on 26 December 2019, doi: 10.1371/journal.pbio.3000559

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