Change of uterine histroph proteins during follicular and luteal phase in pigs

• Uterine histroph protein pattern is promising for understanding of intrauterine environment.
• For the first time, COL4A, MYG, CRP2 and FucT-IV were found in uterine histroph of pig.
• These data may facilitate the prediction of the intrauterine environment.

The aim of this study was to examine protein expression patterns of uterine histroph (UH) during the follicular phase (FP) and luteal phase (LP) in pigs. Forty-nine common proteins were identified from FP and LP samples; five were significantly down-regulated (>1.5-fold), while 15 were significantly up-regulated (>1.5-fold) in LPUH compared with FPUH (P < 0.05). The 20 differentially-expressed proteins are involved in cell proliferation, cell responses, translation, transport, and metabolism and their molecular functions include nucleic acid binding, oxygen activity, enzymatic activity, growth activity, iron binding, and redox binding. Protein expression of vascular endothelial growth factor D (VEGFD), coatomer subunit gamma-2 (G2COP), collagen alpha 4 chain (COL4), cysteine rich protein 2 (CRP2), myoglobin (MYG), and galactoside 3-L-fucosyltransferase 4 (FUT4) was analyzed by Western blotting. These proteins were significantly higher in LPUH compared to FPUH (P < 0.05). These data expand our understanding of changes in the intrauterine environment during the pre-implantation period in pigs.