科学家成功利用骨髓培育出精子

    据4月13日《生殖：配子生物学》杂志刊登的一项研究报告，人骨髓细胞第一次被分化成早期精子细胞，这项科学进展将有助于研究者更多地了解精子的起源。

    这项研究由卡里姆·纳伊尼亚教授主持，纳伊尼亚教授原属德国戈丁根大学大学，现就职于英国纽卡斯尔生命科学中心的英格兰东北干细胞研究所（NESCI）。

    在实验中，纳伊尼亚教授和他的团队从男性志愿者骨髓中分离出间充质干细胞，这些细胞以前被发现可以分化出其它组织细胞如肌细胞。

    这些干细胞在实验室被培养诱导分化成男性生殖细胞，即精子细胞。遗传标记显示存在部分分化的精子细胞即精原细胞——男性生殖细胞发育的早期阶段。大多数男性的精原细胞最终分化发育为成熟、有功能的精子细胞，但是这一过程在实验中尚未实现。

    此前，纳伊尼亚教授主持的对小鼠的研究中，从鼠的骨髓细胞也分化出了精原细胞。这些细胞被移植到睾丸中，观察到它们进行了早期减数分裂（细胞分裂），尽管他们没有进一步分化出成熟的精子细胞。这项成果曾发表在《实验室研究》中。

    谈到新发表的论文，纳伊尼亚教授说，“我们对于这项发现很激动，尤其是我们此前研究鼠的工作提示我们可以做进一步的深入研究。”

     “我们下一个目标是，看能否在实验室里使精原细胞分化出成熟的精子细胞，这大约需要3~5年的时间。我们正在与研究所其他科学家合作开展这项工作。”纳伊尼亚教授说，在伦理和社会可接受的范围内，需要进行长期的科学研究，才能把研究推进到下一阶段，即探讨其在人类生殖治疗中有无潜在的应用价值。

    2006年7月，纳伊尼亚教授获得世人瞩目的是，他在《发育细胞》杂志宣称，他和他的同事从小鼠胚胎干细胞中分化出精子细胞，用这些精子细胞使小鼠卵子受精，诞生了七个新生命。

（原文见http://www.eurekalert.org/pub_releases/2007-04/uonu-esc041107.php）

Early-stage sperm cells created from human bone marrow

Breakthrough will help scientists understand more about how sperm cells are created

Professor Karim Nayernia in his laboratory in Newcastle, England.

    Human bone marrow has been used to create early-stage sperm cells for the first time, a scientific step forward that will help researchers understand more about how sperm cells are created.

  The research published today (Friday, April 13 2007), in the academic journal Reproduction: Gamete Biology, was carried out in Germany by a team of scientists led by Professor Karim Nayernia, formerly of the University of Getingen but now of the North-east England Stem Cell Institute (NESCI), based at the Centre for Life in Newcastle upon Tyne.

  For the experiment, Prof Nayernia and his team took bone marrow from male volunteers and isolated the mesenchymal stem cells. These cells have previously been found to grow into other body tissues such as muscle.

  They cultured these cells in the laboratory and coaxed them into becoming male reproductive cells, which are scientifically known as sperm cells? Genetic markers showed the presence of partly-developed sperm cells called spermatagonial stem cells, which are an early phase of the male germ cell development. In most men, spermatagonial cells eventually develop into mature, functional sperm but this progression was not achieved in this experiment.

How Prof Nayernia and his team cultured from human bone marrow.

  Earlier research led by Prof Nayernia using mice, published in Laboratory Investigations, also created spermatagonial cells from mouse bone marrow. The cells were transplanted into mouse testes and were observed to undergo early meiosis - cell division - the next stage to them becoming mature sperm cells, although they did not develop further.

  Talking about his newly published research paper, Prof Nayernia, of Newcastle University, said : "We're very excited about this discovery, particularly as our earlier work in mice suggests that we could develop this work even further.

  "Our next goal is to see if we can get the spermatagonial stem cells to progress to mature sperm in the laboratory and this should take around three to five years of experiments. It'll be collaborating with other NESCI scientists to take this work forward.

  Prof Nayernia says a lengthy process of scientific investigation is required within a reasonable ethical and social framework to be able to take this work to its next stage or to say if it has potential applications in terms of fertility treatments in humans.

  Prof Nayernia gained worldwide acclaim in July 2006 when he announced in the journal Developmental Cell that he and colleagues had created sperm cells from mouse embryonic stem cells and used these to fertilise mice eggs, resulting in seven live births.