Effects of Glucosamine on the Development and Related Gene Expression of Buffalo (Bubalus bubalis) Embryos

O-linked beta-N-Acetylglucosamine Glycosylation (O-GlcNAc) is one of the main types of glycosylation in mammalian cells while Glucosamine (GlcN) is an O-GlcNAc substrate Thus, effects of GlcN on the embyonic development, level of O-GlcNAc and related gene expression of buffalo embryos were examined m this study Buffalo zygotes derived from In Vitro Fertilization (IVF) were randomly allocated into culture in the medium supplemented with different concentration of GlcN (0, 1, 2 and 4 mM) during the different culture period (0-72, 72-172 and 0-172 h) When GlcN was added to the medium m the culture period of 0-72 h after IVF, addition of 2 mM GlcN resulted m more zygotes developing to blastocysts (26 1%) in comparison with control (14 3%), 1 mM (13 6%) and 4 mM (11 3%) groups (p<0 05) However, the blastocyst yield decreased gradually when GlcN was added to the medium during 72-172 h of culture and decreased significantly when the concentration of GlcN was arrived at 4 mM (3 1 vs 14 2%, p<0 05) When GlcN was added to the medium in the whole culture period (0-172 h) there were no significant difference in either cleavage rate or blastocyst yield among the four groups (p>0 05) Immunofluorescence analysis revealed that addition of 2 mM GlcN to medium from 0-72 h after IVF resulted in a significant increase (p<0 05) m the O-GlcNAc level of embryos at 2, 4, 8 cells and morula stage with the exception of blastocysts QRT-PCR revealed that culture of zygotes with 2 mM GlcN in the culture period of 0-72 h after IVF resulted in a significant increase (p<0 05) m the expression of O-GlcNAc transferase gene in the embryos at the 2, 4, 8 cells and morula stage and did not affect the expression of O-GlcNAc-selective N-acetyl beta-D-glucosaminidase gene These results indicate that appropriate concentration of GlcN can improve the development of buffalo embryos and this action is stage dependent and mediated by O-GlcNAc transferase gene