Therefore much effort today is devoted to the development and improvement of culture media.
Addition of certain substances that would be of importance for early embryo development may be valuable.
Follicular Fluid-Meiosis Activating Sterol (FF-MAS) is a C-29 oxysterol occurring naturally in the biosynthetic pathway between lanosterol and cholesterol and is found in high concentrations in the follicular fluid in the ovaries in mammals including humans (∼1.6 μM) (Byskov , 1995, 2002).
BACKGROUND: The objective of the study was to investigate the effect of Follicular-fluid meiosis activating sterol (FF-MAS) when added to the culture media on the incidence of chromosomal abnormalities and pre-embryo development in human pre-embryos.
METHODS: 243 women undergoing IVF/ICSI treatment donated 353 oocytes in a multicentre, prospective, randomized, double blind, four-arm, controlled trial performed at Danish and Swedish public and private IVF centers.
Metaphase II oocytes were randomly assigned to: FF-MAS 5 μM, FF-MAS 20 μM, ethanol 0.2% (vehicle control) or water for injection (inert control).
The exposure regimen of FF-MAS to the human oocytes was 4 h prior to fertilization by ICSI and 20 h exposure post ICSI.
The primary endpoint was the incidence of numerical chromosomal abnormalities.
Secondary endpoints were cleavage rate and pre-embryo quality.RESULT: On the pre-embryo level, no significant differences in chromosomal abnormality rate were observed among the four groups.However, the percentage of uniformly normal pre-embryos was significantly lower in the pooled FF-MAS group (5 μM: 12% and 20 μM: 17%) than in the pooled control group (inert control 32% and vehicle control 42%).A high level of mosaicism (41–60%) was found in all groups.At the blastomere level, the percentage of blastomeres categorized as normal was significantly lower in the FF-MAS 5 μM group (41%) and the FF-MAS 20 μM (29%) group versus the inert (52%) and the vehicle (61%) groups.Significantly reduced cleavage and good quality pre-embryo rates were found in both FF-MAS groups.