Helicobacter pylori Inhibits Repair of DNA Damage Caused by Oxidative Stress but Does Not Increase Mutation Rate in Host Cells
| Autor: | Jheng Da Song, 宋政達 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Gastric cancer is the world’s second commonest malignancy. The most potential gastric carcinogen responsible for gastric cancer is the infection of Helicobacter pylori, a gram-negative bacterium resident in gastric mucosa. One of the possible mechanisms that H. pylori causes cancer is that it generates large amount of reactive oxygen species (ROS) in gastric mucosa. Our hypothesis is that H. pylori not only produce ROS, but also inhibit repair of the ROS-caused DNA damage. To test this hypothesis, we investigated the repair ability in gastric cells for Bleomycin (BLM)- and MNNG-caused DNA damage after coincubation with H. pylori. Measuring the tail moment with comet assay, we found that the repair of strand breaks induced by BLM significantly decreased in H. pylori-infected cells. Analyzing the hprt mutation rate with 6-thioguanine assay, we found that H. pylori infection does not increase BLM- and MNNG-induced mutation rate. In conclusion, H. pylori may inhibit the repair ability and enhance ROS-induced DNA damage but does not increase mutation in gastric cells. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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