Expression and distribution of cell adhesion-related proteins in bovine parthenogenetic embryos: The effects of oocyte vitrification

The objective was to investigate expression of cell adhesion-related proteins (E-cadherin, β-catenin, and the cytoskeletal protein F-actin) in bovine parthenogenetic embryos derived from vitrified-warmed oocytes. Bovine oocytes at metaphase II were randomly allocated into three groups: (1) untreated (control); (2) exposed to vitrification solution without freezing (toxicity); and (3) vitrified and warmed by the open-pulled straw method (vitrification). After parthenogenetic activation, in the vitrification group compared with the control, the timing of compaction was delayed in (108-120 vs. 96-108 hours, respectively), and the percentage of blastocysts that developed from eight-cell embryos was lower (32.08% vs. 61.03%; P < 0.05). To investigate whether vitrification delayed embryo compaction by affecting adhesion junction formation and function, immunostaining and quantitative reverse transcription polymerase chain reaction were done to characterize distribution patterns (E-cadherin, β-catenin, and the cytoskeletal protein F-actin) and expression levels of cell adhesion-related proteins (β-catenin). Distribution of β-catenin in eight-cell embryos from the vitrification group changed dramatically compared with the control and toxicity groups. Relative expression of β-catenin at the mRNA and protein levels was lower (P < 0.05) than that of the fresh and toxicity groups. However, expression and distribution of E-cadherin were similar among groups. In conclusion, abnormal distribution and decreased expression of β-catenin in bovine parthenogenetic eight-cell embryos derived from vitrified-warmed oocytes were associated with embryo compaction and reduced competence for subsequent embryo development.