Role of MDA in the pathogenesis of GERD esophagus mucosal inflammatory injury

Abstract

Objective To investigate the expression of malondialdehyde (MDA) in esophageal mucosa of different types of gastroesophageal reflux disease (GERD) patients and its role in the esophageal inflammation. Methods According to the inclusion and exclusion criteria, 42 patients hospitalized in the the Xinjiang Uygur Autonomous Region People′s Hospital from December 2017 to October 2018 were selected as the research group. 8 healthy subjects completed physical examination were set up as healthy control group. GERD completed GERDQ score, 24 h pH monitoring, and taken 3 cm on the dentate line of the esophagus as a specimen. The study group was divided into non-erosive reflux disease (NERD) group (17 cases) and Erosive reflux disease [erosive esophagitis (RE)] group (25 cases). Then hematoxylin-eosin (HE) staining, immunohistochemistry, real-time polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA) methods were used to detect inflammation, oxidative stress (MDA), antioxidant enzyme [manganese superoxide dismutase (Mn SOD), glutathione (GSH), catalase (CAT)], and proinflammatory cytokines [monocyte chemotactic protein-1 (MCP-1), interlukin-8 (IL-8), tumor necrosis factor α (TNF- α)]. Results There was no significant difference in body mass index (BMI) between the three groups (P>0.05). 24 h pH monitoring of esophagus showed that the indexes of weak acid reflux (4 0.05). In RE group , the infiltration of immune cells (neutrophils, eosinophils), nipple lengthening, edema and other inflammatory changes were found in the esophageal mucosa, and the inflammation score reached the peak, which was significantly higher than that in NERD group, with statistical significant difference (P<0.001). The positive expression of MDA in the two groups (NERD, RE) was higher than that in the control group, and the MDA expression in the RE group was almost covered with the full layer esophagus.The serum MDA concentration in the NERD and RE groups was significantly higher than that in the control group (P<0.001). Compared with the NERD group, the serum MDA in the RE group reached the peak (P<0.01). The relative expression of mRNA (Mn SOD, GSH and CAT) in NERD group and RE group was significantly decreased, and there was a significant difference between the three groups (P<0.001). Compared with the NERD group, the mRNA expression level of Mn SOD and CAT in RE group was significantly decreased (P<0.01). The relative expression of mRNA (MCP-1, IL-8, TNF- α) increased significantly in the two groups (NERD, RE), and there was a statistically significant difference between the three groups (P<0.001). Compared with the NERD group, the expression of its inflammatory factors in the RE group significantly increased (P<0.01). Conclusions The expression level of MDA in different types of GERD is significantly higher, which may be closely related to esophageal inflammation induced by acid reflux. Key words: Malondialdehyde; Gastroesophageal reflux; Esophageal mucosa; Inflammation; Oxidative stress