Beta transforming growth factors (TGFβ) at the porcine conceptus-maternal interface.: Part I:: Expression of TGFβ1, TGFβ2, and TGFβ3 messenger ribonucleic acids

Spatial and temporal mRNA expression of beta transforming growth factors (TGF beta 1, TGF beta 2, and TGF beta 3) in porcine uterus and conceptuses was determined during the peri-implantation period (Days 10-14 of gestation). Northern blotting identified a major 3.5-kilobase (kb) and a minor 2.5-kb transcript for TGF beta 1 mRNA. TGF beta 2 transcripts were 6.2 kb, 5.4 kb, and 2.7 kb, and a single 3.5-kb transcript was detected for TGF beta 3. With semiquantitative in situ hybridization analysis, progressive increases were detected in TGF beta s 1, 2, and 3 mRNA expression in uterine luminal epithelium (ULE), uterine glands (UGs), and underlying stroma (stroma spongiosum, SS) from Days 10 through 14 of gestation (p < 0.05). In myometrium, TGF beta mRNA expression did not differ between Days 10 through 14 of gestation. In porcine conceptuses, TGF beta s 1, 2, and 3 mRNA expression was detected in trophectoderm, endoderm, embryonic ectoderm, and mesoderm. For the three TGF beta isoforms examined, mRNA expression increased 2- to 4-fold in trophectoderm and endoderm between Days 10 and 14 of gestation. TGF beta 1 mRNA levels increased significantly in embryonic ectoderm, but not mesoderm, between Days 12 and 14 of gestation; during that same time, TGF beta 2 mRNA levels increased, but no change was detected in TGF beta 3 mRNA levels, in embryonic ectoderm and mesoderm. Progressive increases in TGF beta mRNA expression in conceptus trophectoderm, endoderm, ULE, UGs, and SS suggest important roles for these growth factors in porcine conceptus development during the peri-implantation period.