Proteomic profiles of the embryonic chorioamnion and uterine caruncles in buffaloes (Bubalus bubalis) with normal and retarded embryonic development

The aim of this study was to compare the proteome profiles of the chorioamnion and corresponding caruncle for buffalo embryos that had either normal or retarded development on Day 25 after artificial insemination (AI). In experiment 1, embryos that were to subsequently undergo late embryonic mortality had a smaller width on Day 25 after AI than embryos associated with pregnancy on Day 45 after AI. In experiment 2, 25 Italian Mediterranean buffaloes underwent transrectal ultrasonography on Day 25 after AI, and pregnant animals were categorized as one of two groups based on embryonic width: normal embryos (embryonic width > 2.7 mm) and retarded embryos (embryonic width < 2.7 mm). Three buffaloes of each group were slaughtered on Day 27 after AI to collect chorioamnion and caruncle tissues for subsequent proteomic analyses. Two-dimensional difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight mass spectrometer analysis were used to ascertain the proteomic profiles. To confirm 2D-DIGE-results, three selected proteins were analyzed by Western blot. The proteomic profiles of the chorioamnion of retarded embryos and the corresponding caruncles showed differences in the expression of several proteins compared to normal embryos. In particular, a down-regulation was observed for proteins involved in protein folding (HSP 90-alpha, calreticulin), calcium binding (annexin A1, annexin A2), and coagulation (fibrinogen alpha-chain) (P < 0.05), whereas proteins involved in protease inhibition (alpha-1-antiproteinase, serpin H1, serpin A3-8), DNA and RNA binding (heterogeneous nuclear ribonucleoproteins A2/B1 and K), chromosome segregation (serine/threonine-protein phosphatase 2A), cytoskeletal organization (ezrin), cell redox homeostasis (amine oxidase-A), and hemoglobin binding (haptoglobin) were up-regulated (P < 0.05).