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Expression of Cyclooxygenase‐1 and ‐2 in the Porcine Endometrium during the Oestrous Cycle and Early Pregnancy
Author(s) -
Blitek A,
Waclawik A,
Kaczmarek MM,
Stadejek T,
Pejsak Z,
Ziecik AJ
Publication year - 2006
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.2006.00646.x
Subject(s) - estrous cycle , immunostaining , andrology , messenger rna , endometrium , western blot , biology , endocrinology , medicine , immunohistochemistry , cyclooxygenase , enzyme , gene , biochemistry
Contents Cyclooxygenase (COX) is the rate‐limiting enzyme that catalyses the initial step in prostaglandins (PGs) production. In the present studies, endometrial COX‐1 and COX‐2 expression throughout the oestrous cycle and early pregnancy was analysed in pigs using real‐time reverse transcriptase‐polymerase chain reaction (RT‐PCR), Western blot and immunohistochemistry. There were no changes in messenger RNA (mRNA) and protein expression for COX‐1 in cyclic pigs. In pregnant animals, mRNA levels of this enzyme increased on days 22–25 (p < 0.001). However, no upregulation of COX‐1 protein was detected. Quantification of COX‐2 mRNA expression during the oestrous cycle revealed significant increases on days 10–12 and 14 (p < 0.001 and p < 0.01 vs days 2–4, respectively). Protein levels were also increased on day 14 when compared with days 2–12 and 18–20 after oestrus. In pregnant animals, the patterns of both COX‐2 mRNA and protein expression were similar. Messenger RNA levels were higher on days 16 and 22–25 (p < 0.01 vs day 10). Moreover, the protein content tended to increase on days 16 and 22–25. COX‐1 and COX‐2 were localized in the luminal and glandular epithelium as well as in the uterine stroma. In contrast to COX‐1, a positive immunostaining reaction for COX‐2 was detected only on days 12–16 after ovulation and on days 14–16 of pregnancy. In conclusion, these results indicate specific patterns of COX‐1 and COX‐2 expression in the porcine endometrium throughout the oestrous cycle and early pregnancy. COX‐2 rather than COX‐1 seems to be the primary enzyme responsible for modulated PGs production at the time of luteolysis in cyclic and during implantation in pregnant animals.