Defense Date


Document Type


Degree Name

Master of Science



First Advisor

Dorne Yager


The inner surface of the stomach is lined by a mucous membrane known as the gastric mucosa. The integrity of the gastric mucosa is critical for protecting the stomach from the low pH and proteolytic environment within the lumen. Both clinically and experimentally, exposure of gastric mucosal cells to bile salts is known to cause injury. Bile salts present in duodenogastric reflux are thought to play a significant role in gastric ulcer formation and alkaline gastritis. In vitro, studies using physiologic concentrations of the secondary bile salt, deoxycholic acid, indicate that bile salts can induce apoptosis in cultured human gastric epithelial cells in a caspase-dependent manner. Therefore, there is interest in developing approaches that can protect gastric cells from bile salt-induced damage. It has been shown that induction of the stress protein, heme oxygenase-1, can provide protection against apoptosis. Therefore, the objective of this study was to test the hypotheses that heme oxygenase-1 expression could be induced in human gastric epithelial cells and that furthermore; this would provide protection from deoxycholic acid-induced apoptosis. Heme oxygenase-1 expression was induced pharmacologically or by introduction of a plasmid expressing heme oxygenase-1 into the gastric epithelial cell line, AGS. Induction of heme oxygenase-1 prior to challenge with deoxycholate reduced apoptotic-associated morphological changes, DNA fragmentation, the appearance of oligonucleosomes in the cytoplasm, and activation of caspase-3 and caspase-9. Based on these results, it was concluded that expression of heme oxygenase-1, or the introduction of its products, can provide protection to human gastric epithelial cells against sodium deoxycholic acid induced-apoptosis.


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Is Part Of

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Date of Submission

August 2010

Included in

Physiology Commons