Reproduction Abstracts

Introduction: Tight junctions (TJs) are composed of a branching network of sealing strands. TJs regulate paracellular conductance and ionic selectivity. The established paracellular transport barriers that control transportation of molecules within intercellular space.

Methods: We examined expression of mouse placental claudin family. Pregnant C57/BL6 mice were used in this study and TJ proteins including Claudin-1 to Claudin-24 expressions. The pregnant mice were divided into three groups depending on pregnant day (on days 12.5, 16.5, and 20.5 of gestation).

Results and discussion: In the transcription levels, Claudin-1, Claudin-2, Claudin-4, and Claudin-5 expression levels were relatively high expression when compared to other claudin family in all the periods of pregnant. The Claudin-4 expression, which reduces permeability of ions, was increased over a period of time. However, Claudin-5 expression that is the responsive protein for a decrease in paracellular conductance, were decreased. In previous study using the siRNA, Claudin-1 and Claudin-4 has been known as a responsive gene for a decrease in paracellular conductance. On the other hand, Claudin-2 and Claudin-5 has been known as increase paracellular conductance. In addition, immunohistochemistry was performed to identify their localization for inferring permeability in placenta. This study will provide the claudin expressions and their localization in the mouse placenta, which may contribute to assuming the roles of these tight junction genes regarding the maternal–fetal ion transportation in the placenta.