Abstract: Objective To study the expression of nitric oxide synthase（NOS）different isoforms in esophageal epithelium and its correlation with the severity of gastroesophageal reflux disease（GERD）. Methods 80 cases of GERD patients in our hospital during January 2015 to January 2017 were chosen as observation group,50 cases healthy people underwent physical examination at the same period were chosen as normal control group. The expression of nNOS and iNOS in esophageal epithelium in two groups were measured,serum contents of gastrointestinal function,oxidative stress were measured,expression of proliferation genes in esophageal epithelium were detected.Relationship between nNOS and iNOS nRNA in GERD patients and those disease related indexes were evacuated by Pearson test. Results the observation group of patients with lesions of esophageal epithelial expression of nNOS,iNOS mRNA in esophageal epithelium in observation group were higher than those in normal control group（P<0.05）; serum contents of gastrointestinal function indexes such as MTL,GAS,PG I and PG II were significantly lower than those in normal control group,oxidation stress indexes such as SOD was lower than that in normal control group,LPO,MDA were higher than those in normal control group（P<0.05）; expression of proliferation genes such as Ki-67,Caspase-3,WISP2 mRNA in esophageal epithelial were higher than those in normal control group. The Pearson test showed that the expression of nNOS and iNOS in esophageal epithelium in GERD patientswere directly related to the severity of the disease. Conclusion There are abnormally high expression of nNOS and iNOS in esophageal epithelium in GERD patients,and the degree of specific expression is directly related to the severity of the disease. It is one of the important causes of the occurrence and development of GERD.

Key words: Gastroesophageal reflux disease, Nitric oxide synthase, Gastrointestinal function, Oxidative stress, Proliferating gene