Abstract: Tight junction is a fundamental junctional complex of the adjacent epithelial cells，with multiple functions including the barrier effect regulating intercellular permeability and maintaining cellular polarity, which was consisted of several protein families including transmembrane proteins (such as occluding, claudin) and peripheral proteins (such as ZO protein). The structure and function of tight junction can be changed by many physio-/pathological factors such as anoxia, hormonal, inflammatory factors and estrogen. Tight junction has already been detected in human uterine endometrium and placenta. Factors of tight junction expressed in those tissues and organs. Abnormality of tight junction may be involved in the pregnancy complications.

Key words: Tight junctions, Permeability, Cell polarity, Anoxia