In vitro maturation media, cysteamine concentration and glutathione level affect blstocysts development in mouse

Preparation of oocytes is one of the critical factors that determine thedevelopmental competence of embryos produced by in vitro fertilization (IVF).

In this study, the effect of cysteamine, type of media and glutathione (GSH)level on blastocysts development after in vitro maturation of mouse oocytes wereinvestigated.

Premature female mice were primed with pregnant marestimulating gonadotrophin (PMSG), and germinal vesicle (GV) stage oocytes wereobtained 45 hr later. GV oocytes were cultured in presence of 0, 50, 100, 200 and 500μm cysteamine in TCM199 and MEME media. After IVM, MII oocytes were in vitrofertilized (IVF) and in vitro cultured (IVC) in order to observe embryo development. Agroup of In Vivo Ovulated (IVO) oocytes after priming with PMSG and HCG also wereincluded in this study. 5,5-Dithio-bis (2nitrobenzoic acid) DTNB-recycling protocolwas used for GSH assay.

Rate of IVM and IVF were improved in all oocytes treated with cysteamine inthe two medium except 500 μm (81% MII rate in TCM and 64% MII in MEME). Rateof blastocyst in 100 μm cysteamine in TCM1199 and 200 μm in MEME was highercompared to control groups (In TCM 45% and in MEME 35%). In vivo MII and GVoocytes represented the highest and lowest GSH level respectively.

Our results revealed that the media and concentration of cysteamine canaffects on IVM, IVF and rate of blastocysts development on dose dependant manner.