Background: Research studies on reproductive mechanism of laboratory animals are essential for further advancement of assisted reproductive techniques (ART). One of these studies includes the assessment of the effect of types of sera in culture medium on development of pre-implantation embryos. This study evaluated for the first time the effect of different protein supplements (BSA), mouse serum and mouse serum which treated by casein; on development, ICM, TE and apoptotic cell number and expression of Oct4, Cdx2, Bax, Bcl2 and recep-tor of
GM-CSF (Csf2ra) genes in blastocysts of NMRI strain mouse.Materials and Methods: Mice were injected IP with 2 ml of 0.2% (wt/vol) solution of casein in mouse tonicity phosphate-buffered saline (MTPBS) and at 3 hours after injection blood collected from heart and serum separated. Two pro-nucleuses stage embryos from in vivo were collected by oviduct flush-ing. The 2PN’s were randomly divided into three groups. 1) culture medium supplemented with 4mg/ml bovine albumin serum (BSA), 2) culture medium supplemented with 10% mouse serum (M), and 3) culture medium supplemented with 10% mouse serum that treated by casein. Then embryos were cultured up to the blastocyst stage. In 4th group embryos were developed in-vivo in to blastocyst stage. The rate of blastocyst development, apoptotic rate and number of Inner cell mass and Trophectoderm of blastocysts were measured, also quantitative expression of Oct4, Cdx-2, Bax, Bcl-2 and
GM-CSF receptor (Csf2ra) were performed in these groups, using RNA extraction and Real Time PCR.Results: Serum
GM-CSF levels were measured by ELISA kit0.348 ɳg/ml. The difference in the percentages of development to blastocyst stage in culture medium containing BSA, M, treat-ed M serum by casein and in-vivo groups were not significant. There were no significant difference between ICM numbers but TE and total cells of blastocyst were significantly increased in in vitro groups. Embryos that cultured with BSA had significantly more apoptotic cells in comparison the other groups. Quantita-tive PCR analysis showed that the difference in the expression level of Oct4, Cdx2, Bax, Bcl2 and
Csf2ra was not significant. Conclusion: In this study developmental rate was similar to embryos that cultured in 2 ɳg/ml recombinant
GM-CSF even though serum
GM-CSF levels didn’t increase up to optimized dose (2 ɳg/ml). Considering the fact that the
GM-CSF is endog-enous and appropriate developmental rate usage of this serum could be a possible alternative.