Phospholipase A(2) and cyclooxygenase gene expression in human preimplantation embryos

J Clin Endocrinol Metab. 2002 Jun;87(6):2629-34. doi: 10.1210/jcem.87.6.8532.


Phospholipase A(2) (PLA(2)) and cyclooxygenase (COX) are two key enzymes in PG synthesis; the latter has two forms, COX-1 and COX-2. mRNA was extracted from single preimplantation embryos and examined for PLA(2), COX-1, and COX-2 gene expression by RT-PCR to investigate whether PLA(2) and COX genes are expressed in human preimplantation conceptuses from zygote to blastocyst stage and to compare COX-1 and COX-2 gene expression within the same stage of embryonic development. Expression of PLA(2), COX-1, and COX-2 was detected in 48, 37, and 45%, respectively, of total embryos examined. COX-1 was expressed in approximately 66% of early human preimplantation embryos from zygote to two-cell stage, whereas COX-2 was expressed in about 58% of later stage embryos from eight-cell to blastocyst stage (P < 0.05). Furthermore, COX-2 mRNA and protein were localized to trophectoderm in blastocyst stage embryos. In conclusion, PLA(2), COX-1, and COX-2 are expressed during early human embryonic development and may contribute to the production of PGs such as PGE(2) in human embryogenesis. COX-1 and COX-2 are differentially expressed, with COX-2 being primarily expressed by trophectoderm in late-stage human preimplantation embryos, which may promote embryonic differentiation and implantation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blastocyst / physiology*
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • Embryonic and Fetal Development
  • Gene Expression*
  • Humans
  • Isoenzymes / genetics*
  • Membrane Proteins
  • Phospholipases A / genetics*
  • Prostaglandin-Endoperoxide Synthases / genetics*
  • RNA, Messenger / metabolism


  • Isoenzymes
  • Membrane Proteins
  • RNA, Messenger
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • PTGS1 protein, human
  • PTGS2 protein, human
  • Prostaglandin-Endoperoxide Synthases
  • Phospholipases A