The Role Of Oxidative Stress In The Pathogenesis Of Esophageal Mucosa Injury In Children With Reflux Esophagitis

Background and Objective Acid reflux, bile reflux and their mixed reflux were regarded as the main pathogenesis of gastroesophageal reflux disease (GERD) and its complications, and the chief factors in the development of esophageal mucosa injury, but the mechanism is still unclear. Oxidative stress can cause directly biomembrane lipid peroxidation, protein and enzyme denaturation and DNA injury, which lead to cell apoptosis and tissue damage eventually. Therefore, oxidative stress have constituted the pathologic foundation of many diseases. This study aims to investigate the effects of oxidative stress in the pathogenesis of esophageal mucosa injury in children with reflux esophagitis (RE).Methods Gastroscopy and two biopsies of lower esophageal mucosa were performed in fifty-six patients aged 7 months to 16 years having gastrointestinal symptoms such as nausea, vomiting, heartburn, hematemesis and upper abdominal pain. One esophageal sample was fixed with 10% methanal and stained with routine HE, and then histopathological analysis was performed by light microscope. Another sample was weighted with electronic balance, and then manufactured 0.5-1.0% homogenate according the weight. The supernatant was store in -80 centidegree to be used for detecting. Protein content, the parameters such as malondialdehyde (MDA), glutathione (GSH) , nitric oxide (NO)and total superoxide dismutase (T-SOD)were determined in esophageal mucosa by colorimetric method.Results Fifty-six patients had gastroscopy were divided into RE group and NE group according to the esophageal mucosa injury and pathological changes. RE group consisted of 36 cases (male 26 and female 10) aged from 7 months to 16 years (average 9.3 ±3.9 years). NE group consisted of 20 subjects (male 12 and female 8) aged from 3 years to 16 years (average 10.3±3.3 years). The difference of sex and age between the two groups had not reached significance (P>0.05). The content of protein in the esophageal mucosa was no significant between the two groups (P>0.05). Thelevel of MDA(nmol/g prot)in RE group (15.36±16.67) was significantly increased than that in NE group (7.51±6.17) (P<0.01). The activity of T-SOD (U/mg prot) in RE group (30.43±35.09 ) was statistically decreased than that in NE group (56.34±51.73) (P<0.05). No significant difference of GSH (mg/g prot) was observed between the two groups (1298.47±770.51 and 1345.47± 1049.93, respectively) (P>0.05). The amount of NO (umol/g prot) in RE group (743.89±469.69) was not significantly different from those in NE group (649.38±559.45)(P>0.05).Conclusion Significantly increased amount of MDA and decreased level of SOD were observed in children with reflux esophagitis suggested that oxidative stress seems to be one of the important mediators in generation of esophageal mucosa injury.