Fertility and Sterility, Volume 74, Issue 6, December 2000, Pages 1142-1147

Yoshiyuki Kojima M.D., Shoichi Sasaki M.D., Yasue Kubota M.D.,
Takahito Ikeuchi M.D., Yutaro Hayashi M.D., and Kenjiro
Kohri M.D.; Department of Urology, Nagoya City University Medical School, Nagoya, Japan

Received 28 January 2000; revised 1 June 2000; accepted 1 June 2000.
Available online 18 December 2000.


Objective: To study the effects of simulated microgravity on
mammalian fertilization and preimplantation embryonic development in
vitro with the use of a horizontal clinostat device.

Animal(s): B6D2F1 (C57BL/6 ? DBA/2) and ICR mice between 8 and 10 weeks old.

Intervention(s): The first experiment was performed to investigate
whether gravity is required for fertilization in vitro under three
conditions: clinostat rotation, rotational control, and stationary
control. In the second experiment, one-cell embryos were cultured
under each condition and their morphology and viability were
assessed at 96 hours.

Main Outcome Measure(s): The fertilized numbers and embryonic
numbers at the morula and blastocyst stages were recorded in each

Result(s): In the first experiment, there were no statistically
significant differences in the efficiency of achieving normal
fertilization in vitro among the conditions. In the second
experiment, 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.

Conclusion(s): These results suggest that the process of
fertilization in vitro is not sensitive to the gravitational vector.
However, the possibility exists that the frequency of early
embryonic lethality is increased by microgravity.