ABSTRACT
Background: Ammonium is produced in culture medium due to amino acids degradationand has adverse effect on in vitro culture of embryo. In the current study, thepurpose was to evaluate the effects of ammuniom chloride [AC] on in vitro oocytematuration rate and early embryo development in the sheep and its effect on the expressionof Bcl-2
Methods: In vitro maturation [IVM] was performed in the presence of various concentrations[0, 29, 88,132,176 M/ml] of ammonium chloride [NH4CL][AC]. Meioticmaturation, embryonic development and expression of Bcl2 gene in Blastocystcells were determined. The data were analyzed by one-way ANOVA and Tukey postHOC test, and values with p<0.05 were considered statistically significant
Results: The highest concentration [176micro M] of AC significantly decreased the rateof fully expanded cumulus cells 24 hr after IVM compared with the control group[p<0.05]. Moreover, significantly lower rates of MII oocytes were found in the 176micro M AC group compared with the 29micro M AC group. The percentage of zygotes developingto blastocysts in 176micro M AC was lower than the other group. Also, supplementationof the oocyte maturation media with 176micro M AC decreased Bcl2 expression
Conclusion: Our results suggested that significant increase in IVM rate could be obtainedwith supplementation maturation medium with AC in a dose dependent manner.Increased AC concentration led to lower blastocyst rate under normal condition.However, regulation of pro-apoptotic [Bcl-2] gene did not change with differentconcentrations of AC supplementing