日本理化学研究所和广岛大学共同成立的研究小组在8月25日出版的美国《公共科学图书馆·综合》（PLoS ONE）杂志上发表的一项研究成果指出：在国际空间站、航天飞机等接近失重的环境中，老鼠受精卵的发育会受到抑制，产仔率也大幅下降。

这一结果表明同为哺乳动物的人类可能也很难在太空繁衍后代。理化学研究所发生和再生科学综合研究中心(神户市)的研究小组组长若山照彦表示“通过调查受精卵发育需要多少重力，或许可以知道是否有可能在月面基地培育后代。”

研究人员使用特殊装置通过让实验容器旋转制造出地面重力千分之一的微重力环境，调查其对老鼠体外受精和产仔造成的影响。

结果发现，虽然能正常受精，但在受精卵分裂过程中，胎盘一侧聚集的细胞数少于通常情况，发育速度也有所减慢。将其注入雌鼠子宫之后可以正常产仔，但产仔率下降了将近一半。

过去开展的太空实验表明，鱼类和两栖类可以在太空正常发育。研究小组分析认为“造成这一状况可能是因为哺乳动物特有的胎盘的发育和重力有关”。

推荐原始出处：

PLoS ONE 4(8): e6753. doi:10.1371/journal.pone.0006753

Detrimental Effects of Microgravity on Mouse Preimplantation Development In Vitro

Sayaka Wakayama1, Yumi Kawahara2, Chong Li1,3, Kazuo Yamagata1, Louis Yuge2, Teruhiko Wakayama1,3*

1 Laboratory for Genomic Reprogramming, RIKEN, Center for Developmental Biology, Kobe, Japan, 2 Division of Bio-Environment Adaptation Sciences, Graduate School of Health Sciences, and Space Bio-Laboratories, Hiroshima University, Hiroshima, Japan, 3 Department of Bioscience, Graduate School of Science and Technology, Kwansei Gakuin University, Sanda, Japan

Sustaining life beyond Earth either on space stations or on other planets will require a clear understanding of how the space environment affects key phases of mammalian reproduction. However, because of the difficulty of doing such experiments in mammals, most studies of reproduction in space have been carried out with other taxa, such as sea urchins, fish, amphibians or birds. Here, we studied the possibility of mammalian fertilization and preimplantation development under microgravity (μG) conditions using a three-dimensional (3D) clinostat, which faithfully simulates 10–3 G using 3D rotation. Fertilization occurred normally in vitro under μG. However, although we obtained 75 healthy offspring from μG-fertilized and -cultured embryos after transfer to recipient females, the birth rate was lower than among the 1G controls. Immunostaining demonstrated that in vitro culture under μG caused slower development and fewer trophectoderm cells than in 1G controls but did not affect polarization of the blastocyst. These results suggest for the first time that fertilization can occur normally under μG environment in a mammal, but normal preimplantation embryo development might require 1G.