title: Production of reactive oxygen species by gastric cells in association with Helicobacter pylori.
abstract: Reactive oxygen species (ROS) and Helicobacter pylori have been identified as pathogenic factors in several gastrointestinal disorders. Since little information is available regarding the mechanistic pathways of H. pylori-induced gastric injury, the potential role of ROS was investigated. The induction of ROS in gastric cells (GC) by H. pylori was assessed using chemiluminescence, cytochrome c reduction, nitrobluetetrazolium (NBT) reduction and lactate dehydrogenase (LDH) leakage. The dose-dependent protective abilities of selected ROS scavengers on LDH leakage were determined. Following incubation of GC with three strains of H. pylori (1:1), approximately 5.7-8.0 and 3.8-4.3 fold increases were observed in cytochrome c and NBT reduction, respectively, demonstrating production of ROS. Enhanced chemiluminescence responses of 2.1- and 3.7-fold were observed following incubation of GC with H. pylori (ATCC 43504) at ratios of 1:1 and 1:10, respectively. Approximately 2.2- and 3.5-fold increases in LDH leakage were observed at GC:H. pylori (ATCC 43504) ratios of 1:1 and 1:10, respectively. Substantial inhibition of LDH leakage from GC in the presence of H. pylori was observed following co-incubations with selected ROS scavengers with cimetidine serving as the best chemoprotectant. The antioxidants and H2-receptor antagonists had no effect on growth of H. pylori cells. This study demonstrates that H. pylori induces enhanced production of ROS in GC, and enhances membrane damage.
authors.affiliation: Department of Pharmaceutical, Creighton University, Omaha, NE 68178, USA.
authors.forename: D
authors.initials: D
authors.lastname: Bagchi
authors.forename: G
authors.initials: G
authors.lastname: Bhattacharya
authors.forename: S J
authors.initials: SJ
authors.lastname: Stohs
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D002470:Cell Survival; D016166:Free Radical Scavengers / Q000494:pharmacology; D005753:Gastric Mucosa / Q000378:metabolism; D016481:Helicobacter Infections / Q000503:physiopathology*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008163:Luminescent Measurements; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013270:Stomach / Q000382:microbiology*; D013481:Superoxides / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D006635:Histamine H2 Antagonists; D017382:Reactive Oxygen Species; D013481:Superoxides; D007770:L-Lactate Dehydrogenase