宇宙での男子妊孕性

Abstract

擬似的な微小重力環境における哺乳類の造精機能や精子運動性, 受精, 初期発生に対する影響を検討した.微小重力環境における頭側への体液移動モデルである尾部懸垂マウスでは, 精巣/体重比と血清テストステロン値が有意に減少した.ジェット機のパラボリックフライトにより作り出された微小重力環境においてヒト精子運動能は低下した.クリノスタットを利用した擬似微小重力環境下では体外受精の受精率には影響しなかったが, 96時間の培養でマウス受精卵が桑実胚および胞胚形成した割合は有意に少なかった.微小重力環境下では, 精巣萎縮とテストステロン産生低下をきたし, 精子運動性の低下を認めるが, 受精能には影響を与えず, 受精卵の初期発生には障害を及ぼす可能性がある

The effects of simulated microgravity on mammalian reproduction were studied using tail-suspended mice, during parabolic flight in a jet plane and in a horizontal clinostat device. In the tail-suspended mouse, which is a model of the shift of body fluid in a microgravity environment, atrophy of the testis and decrease of serum testosterone level were observed. The sperm motility decreased in the muG condition produced by the parabolic flight. There were no statistically significant differences in the efficiency of achieving normal fertilization in vitro, but there was a statistically significant decrease in the number of embryos reaching the morula and blastocyst stages after 96 hours in culture under clinostat rotation. These results suggest that the process of fertilization in vitro is not sensitive to the gravitational vector. However, the possibility exists that microgravity increases the disturbance of spermatogenesis and sperm motility or the frequency of early embryonic lethality. On the possibility of reproduction in space, there are some problems such as the cosmic radiation besides gravity. It is necessary to carry out further experiments in outer space.