Influence Of Estrogen And H.pylori On Human Duodenal Mucosal Bicarbonate Transport Protein

Backgrounds&Purpose:Duodenal mucosal bicarbonate secretion is an important protective factor of duodenal mucosa against acid-induced injury. In this study, we investigated the influence of estrogen and H.pylori on human duodenal mucosal bicarbonate transport protein. We expected to further elucidate the cellular mechanisms whereby estrogen increases duodenal mucosal bicarbonate secretion and pathogenesis of H.pylori-related duodenal ulcer.Methods:Healthy female volunteers in the 20-30 years without H.pylori infection confirmed by C-14 breath test were selected. During their ovulatory periods and menstrual periods which is considered as the peak and low values of estrogen production in female menstrual cycle, duodenal mucosa was taken by endscopic biopsy for mRNA expression analysis of duodenal mucosal bicarbonate transport protein CFTR, SLC26A3, and SLC26A6 and venous blood was taken for serum estrogen measurement. In addition, healthy female volunteers in the 20-30 years and 60-70 years, and healthy male volunteers in the 20-30 years and 60-70 years were also selected. All subjects were H. pylori-negative which was confirmed by rapid urease test. Duodenal mucosa was taken by endoscopic biopsy for mRNA and protein expression analysis of CFTR, SLC26A3, and SLC26A6. Selecting patients with H.pylori-infected duodenal ulcer and H.pylori-infected chronic gastritis in the age of 20-40 years, and healthy controls without H.pylori infection in the age of 20-40 years, duodenal mucosa was taken for mRNA expression analysis of CFTR, SLC26A3, and SLC26A6.Results:strogen levels in women's ovulatory and menstrual periods were 592±171pmol/L and 242±86pmol/L, respectively. RT-PCR results showed that there was no significant difference in the mRNA expression of CFTR, SLC26A3, SLC26A6 between women's ovulatory and menstrual periods (p>0.05). The CFTR mRNA expression of normal female in the age of 20-30 years was markedly higher than those of male in the age 20-30 years and 60-70 yaers, and female in the age of 60-70 years (P<0.05), but there were no significant differences between males of 20-30 years and 60-70 years, and females of 60-70 years (P>0.05). There were no significant differences SLC26A3, SLC26A6 mRNA expressions between them (p>0.05). Likewise, the expression of CFTR protein of female in the age of 20-30 years by western-blot was higher than those in females of 60-70 years and males 20-30 years and 60-70 years (P<0.05). mRNA expressions of SLC26A6 in patients with H.pylori-infected duodenal ulcer and chronic gastritis were decreased in comparison with healthy controls without H.pylori infection (P<0.05), but there were no significant differences in mRNA expression fo CFTR and SLC26A3 between them (P>0.05).Conclusion:The results indicate that female estrogen might regulate the expression of duodenal mucosal bicarbonate transport protein CFTR, and H.prlori reduces SLC26A6 expression, which is contributed to elucidate the mechanisms whereby estrogen increases duodenal bicarbonate secretion and the pathogenesis of H.pylori-associated duodenal ulcer.