The Effects of Dexamethasone on Claudin Tight Junction proteins in 18-day Embryonic Chick Intestine

Claudin (cldn) protein family is the main component of tight junction (TJ) strands and it is directly involved in the barrier function of TJs. In addition to the contributing to the barrier function of TJs in mature tissues, these junctions are also present and required for normal embryonic development of epithelial sheets. Glucocorticoids (GC) are essential for the maturation of numerous tissues including the intestine during embryonic development. They also have stimulatory effects on the integrity of tight junctions. In this study, the effect of a synthetic glucocorticoid, dexamethasone (DEX) on mRNA expression of tight junctional proteins was investigated in 18-day embryonic chick intestine in vitro using quantitative Real-Time PCR (RT-PCR) analyses. Pre-hatched chick intestine will provide a convenient model because the organization of the barrier is not completely established, and it is relatively easy to maintain its morphological integrity for at least 24 hours in an organ culture system. RT-PCR analyses revealed that both claudin-3 (cldn-3) and claudin-5 (cldn-5) tight junction gene expressions were induced in response to DEX in a dose dependent manner