[66]

A major effect of simulated microgravity on preimplantation mouse development is lethality   Daniel A. Rappolee1, Yingchun Wang, Yufen Xie, Dana Wygle1, Hayley Shen2, and Elizabeth Puscheck1,    1Department of Obstetrics and Gynecology, Hutzel Hospital, Wayne State Univ School of Medicine, Detroit MI, 48201. 2Department of Civil & Environmental Engineering Clarkson Univ Potsdam, NY 13699-5710.

   We tested whether microgravity has effects on preimplantation mouse embryo development after fertilization. Embryos were put into rotating wall vessel cell culture system (RCCS, Synthecon) at 7.5RPM after being obtained at 1.5 days after fertilization (E1.5 2-cell), E2.5  (8-cell) or E3.5 (blastocyst) in microgravity simulation (MGS) or rotational control (RC) or put in normal IVF culture as static control (SC). The rotational velocity in MGS developed approximately simulated 0.1% gravity. After 24hr of rotation, embryos were removed from the RCCS and cultured in static culture to test for recovery. For each of the three ages of embryos obtained, we tested for morbidity, lethality, and progression to the next key developmental event as criteria for MGS and RC effects. We assayed for signs of morbidity and lethality, failure to proliferate immediately after rotation or after 24hr or 48hr 'recovery' in static culture. We assayed total number and fraction of embryos developed to the next crucial developmental stage. We tested for activation of SAPK/JNK phospho. MGS results in lethality and E2.5 is more critical than E1.5 or E3.5 in preimplantation development. At peak sensitivity, RC is as lethal, but has a delayed lethality compared with MGS. SAPK phospho is activated in MGS. MGS simulation causes lethality, a novel phenotype not often observed in microgravity or MGS. The most sensitive period of lethality is at compaction at E2.5, but E1.5 and E3.5 lethal for most embryos. RC also causes morbidity and lethality, but these are less severe and slower than MGS. SAPK/JNK activation is associated with lethality. Research support by grants from NASA (NRA-NAG2-1503) and the NIH, (R01-HD40972).