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【科普】新西兰研究发现抗氧化剂或促男性生育
提观点
新西兰奥克兰大学研究人员把研究对象锁定为生育能力低的男性，即生育能力低于平均水平但仍能生育。
路透社1月20日报道，统计结果显示，每20名男性中会有一人承受低生育能力困扰，夫妇晚育一半源于男性生育能力低。医学专家认为，男性生育能力低80%是因为精子受到氧化，数量减少，质量降低。
精子氧化由一种名为自由基的分子引发。自由基是细胞新陈代谢产物，具有强氧化性，可损伤机体组织和细胞功能。抗氧化剂含有某些维生素和营养成分，能够帮助细胞抵御自由基损伤。
一些学者设想，男性服用抗氧化剂或许能够帮助精子保持游动能力。研究人员回顾以往生殖研究，希望获得数据，支持这一观点。
溯研究
研究人员回顾34项生育治疗研究，涉及近3000对夫妇。治疗方法包括体外受精和宫腔内人工受精，即两种针对男性精子质量低所致不孕症的最常用方法。
分析15项研究中96个成功受孕案例，研究人员发现，男性服用抗氧化剂后，生育能力增强4倍多，配偶分娩活胎的可能性增加5倍。
研究项目主管玛丽安·肖维尔说：“口服抗氧化剂可能在一定程度上提高夫妻受孕几率。”
研究报告由网上医学电子杂志《科克伦图书馆》（The Cochrane Library）发表。不过，研究人员认为，抗氧化剂增强男性生育能力的观点并非绝对正确，有待更多研究结果加以确认。
遭质疑
这项研究遭到一些生育专家质疑。美国伊利诺伊大学泌尿学教授劳伦斯·罗斯说：“男性精子功能存在障碍，不查明原因而单纯借助抗氧化剂施行治疗不合适。”
另一些专家质疑研究方法和研究对象数量。研究人员回顾的34项研究中，没有一项研究的参与人数超过1000人，一些研究仅10人参与。
美国布朗大学教授马克·西格曼说：“研究表明，抗氧化剂能够提高婴儿安全出生可能性，这一结论仅以20个案例为依据，样本数量相对较少。”他认定，研究涉及的抗氧化剂种类和数量不同，无法确定每一种抗氧化剂的效用。
“一种治疗方法对多数夫妻有效的想法不现实，”西格曼说，“虽然没有证据表明抗氧化剂有害人体健康，但我们不清楚哪一种抗氧化剂或者多少剂量能够增强生育能力，没有一种抗氧化剂获得（美国）食品和药物管理局批准用于不孕不育症治疗，消费者不应该偏听偏信。”
Antioxidants may improve male fertility
(Reuters Health) - Couples who struggle to conceive could find baby-making help from antioxidants such as vitamin E and zinc, hints a new review of more than 30 studies.
The researchers focused on men who were subfertile -- less fertile than average but still capable of making a baby -- and found that those who took antioxidants were more than four times as likely to get their partners pregnant than subfertile men who did not take the supplements.
The New Zealand team stops short of saying that antioxidants actually improve fertility, however. More research is needed to be sure.
Subfertility affects one in 20 men and is responsible for half of delayed conceptions. Up to 80 percent of cases are thought to be due to the effects of oxidative stress on sperm cells, lowering both their numbers and their quality.
Oxidative stress happens when molecules known as free radicals, byproducts of cell metabolism, damage DNA and cells' ability to function. Antioxidants, including certain vitamins and nutrients, help to protect cells by stabilizing free radicals.
This has led some experts to wonder if antioxidants might help sperm stay swimmingly healthy.
"Oral supplementation with antioxidants may go some way to improve a couple's chance of conception," lead researcher Marian Showell of the University of Auckland, in New Zealand, told Reuters Health in an e-mail.
To see if the research to date backs up that idea, Showell and her colleagues reviewed 34 studies that involved nearly 3,000 couples undergoing fertility treatments, including in vitro fertilization and intrauterine insemination -- two of the most commonly used methods of boosting conception odds when sperm-related issues are involved. Each study investigated the potential role of one or more antioxidants.
Based on 96 pregnancies among 964 couples in 15 of the studies, the researchers found that antioxidant use by the male partner increased the odds of conception four-fold.
Further, men taking antioxidants improved the likelihood of their partners giving birth to a live baby by a factor of five, the researchers report in The Cochrane Library. Only three of the studies contained data on live births, however.
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作者:admin@医学,生命科学 2011-01-24 13:12
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