The immunolocalization of Galectin-1 and Progesterone-Induced Blocking Factor (PIBF) in equine trophoblast: Possible roles in trophoblast invasion and the immunological protection of pregnancy.

The research investigates the presence and potential roles of galectin-1 and Progesterone Induced Blocking Factor (PIBF) proteins in equine pregnancies, particularly in relation to trophoblast invasion and immunological protection.

Objective of the Study

• The primary objective of the study was to determine whether galectin-1 or Progesterone Induced Blocking Factor (PIBF), two proteins found on human and murine trophoblast, could be immunolocalised in either the invasive or non-invasive components of the equine placenta.

Methodology

• Equine embryos and placental tissues between Days 12 and 124 of gestation were studied.
• Immunohistochemical staining was performed with antibodies raised against galectin-1 and PIBF.
• Different stages of gestation were observed to detect the presence and location of these proteins.

Findings

• Galectin-1 stained the non-invasive trophoblast from Days 15 to 20, and then transitioned to staining only the invasive trophoblast cells known as the chorionic girdle.
• PIBF was located in both the invasive and non-invasive trophoblast throughout the period of gestation studied.
• In mule pregnancies, there was a marked reduction in the staining of the endometrial cup cells prior to their premature death and desquamation, compared to horse pregnancies.

Conclusion

• The differences in protein expression suggest a likely role for galectin-1 and PIBF in shielding the fetal trophoblast from maternal immune attack. They might also influence the invasiveness of endometrial cup cells.
• The difference in lifespan between the endometrial cups in horse pregnancies compare to mule pregnancies further supports the potential significance of these proteins.