Chemiluminescence assay of mucosal reactive oxygen species in gastric cancer, ulcer and antral mucosa

Background/Aims: Reactive oxygen species (ROS) have been implicated in inflammatory and cancerous illness, including that of the gastrointestinal tract. The oxidative damage incurred during human gastric ulcer or cancer mucosa may be related to acumination of ROS. In this study, we aimed to demonstrate oxidative stress of gastric ulcer and cancer mucosa compared to gastric antral mucosa. Methodology: Patients: Thirty-four patients with gastric ulcer and gastric cancer were enrolled in this study. Gastric mucosa specimens, taken from upper GI endoscopic biopsy, from the lesion (ulcer or cancer) and antrum were sent for the activity of O-2(-) or H2O2 determined by chemiluminescence assay. Protein concentrations in the tissue homogenates were determined by Bio-Red protein assay. The production of O-2(-) or H2O2 per unit of protein was calculated by dividing the tissue CL level by the protein content of a tissue. Results: The oxidative stress metabolites O-2(-) and H2O2 of mucosa were evaluated by chemiluminescence assay in gastric lesions (27 ulcers and 7 cancers) and gastric antrum. Gastric lesion showed significantly increased O-2(-) than antral mucosa (18.77+/-45.18 (counts/sec . mu g), 95% CI 3.01, 34.53 vs. 3.58+/-6.89 (counts/sec . mu g), 95% CI 1.18, 5.98, p<0.05). There was also significantly greater expression of H2O2 in gastric lesion than gastric antral mucosa (76.06+/-148.36 (counts/sec . mu g), 95% CI 24.30, 127.83 vs. 912.41+/-20.22 (counts/sec . mu g), 95% CI 5.35, 19.46, p=0.008). Differences of mucosal O-2(-) and H2O2 between gastric ulcer and cancer were not significant. There was significant correlation of O-2(-) and H2O2 generation in gastric lesion mucosa. Conclusions: Oxidative stress is now thought to make a significant contribution to inflammatory disease and malignancy. The reason that overproduction of free radicals is a feature of such a broad spectrum of diseases derived from the fact that oxidative metabolism is a necessary part of every cell's metabolism. In this study, we demonstrated increased ROS production in gastric ulceration and cancer compared with gastric antral mucosa.