Poster Topical Area: Aging and Chronic Disease
Poster Board Number: 94
OBJECTIVES: The decline in estrogen levels during the menopausal transition is associated with increased adiposity, which may be due in part to compromised integrity of the small intestinal epithelial barrier. The influence of estrogen on tight junction protein expression and integrity of the epithelial barrier has been explored in other tissues, but not the small intestine. The purpose of this project is to determine the extent to which estrogen deficiency affects the expression of tight junction proteins in the small intestine.
METHODS: Duodenal tissue from 17-week-old Sprague Dawley rats was collected two weeks post-ovariectomy (OVX) with or without exogenous 17β-estradiol administration (0.5 mg or 1.5 mg 90-day release pellet). Body weights were recorded weekly and prior to tissue collection. Expression of tight junction proteins was assessed via Western blot. Differences between groups in body weight and tight junction protein expression were analyzed via ANOVA using SAS 9.3.
RESULTS: Body weights of OVX rats without exogenous 17β-estradiol administration were significantly higher than those of the OVX rats receiving either dose of 17β-estradiol. Expression of tight junction proteins occludin and junctional adhesion molecule A (JAM-A) was significantly up-regulated by both doses of 17β-estradiol in the duodenum.
CONCLUSIONS: To our knowledge, the regulation of tight junction proteins by estrogen has not been reported in the small intestine. This study suggests that down-regulation of tight junction proteins may predispose postmenopausal women to pathophysiologies which result from increased intestinal permeability. Future work will focus on elucidating the mechanism(s) by which estrogen regulates tight junction protein expression and how this may contribute to the increased incidence of various chronic inflammation-associated diseases after menopause. Additionally, a future goal will be to identify food components that may attenuate the down-regulation of tight junction proteins expression in this model.
Funding Source: College of Allied Health Research Seed Grant Program
The University of Oklahoma Health Sciences Center
Oklahoma City, Oklahoma