Dose-dependent effect of sphingosine-1-phosphate in mouse oocyte maturation medium on subsequent embryo development

To investigate the dose-dependent effect of sphingosine-1-phosphate (S1P) supplementation on meiotic maturation, apoptosis and developmental competence of immature mouse oocytes.

Immature oocytes from 5- to 6-week-old BDF1 mice were incubated in maturation medium containing S1P with six different doses (10 nM, 50 nM, 100 nM, 500 nM, 1 μM, and 2 μM) for 18-19 h. Fertilization and blastocyst formation was assessed. All blastocysts were stained by anti-caspase antibody.

Treatment with 100 nM, 500 nM and 1 μM S1P showed significantly higher blastulation rate [66.0, 62.1 and 66.2%, respectively, p < 0.05 when compared with control (40.0%)]. Blastomere count was similar across six treatment groups, but the percentage of apoptotic blastomere was significantly lower in the 100 nM, 500 nM, and 2 μM S1P-treated groups [5.4, 6.5, and 3.7%, respectively, p < 0.05 when compared with control (10.6%)].

Considering the blastulation rate together with the apoptotic event in the blastocysts, adding 100 and 500 nM S1P within oocyte maturation medium could be beneficial in the development of immature mouse oocytes.