Abstract: Abstract: Objective　To observe the protective effect of CDDO-Me on the esophageal mucosal barrier, and explore the feasibility of CDDO-Me as a mucosal barrier enhancer. Methods　The Het-1A cell lines were treated with acids of different pH values (pH4, pH5, pH6) for 5, 10, 30 and 60 min. The changes of the transepithelial electrical impedance (TEER) value of Het-1A cell line were detected. The Het-1A cell line was pre-stimulated with different concentrations of CDDO-Me (0, 0.25, 0.5, 1, 2.5 and 5 μmol/L), and then the Het-1A cell line was treated with acid to observe changes of TEER values. Results　There were significant differences in the effects of pH treatment (pH4, pH5 and pH6) on the TEER of Het-1A cells (P＜0.01). With the increase of the treatment time (10, 30 and 60 min), the decrease of TEER was larger. When the treatment time was 10, 30, and 60 min, there were  significant differences between the groups, and the TEER decreased most significantly in the pH4 group at 60 min (P＜0.01). After CDDO-Me pre-stimulation, the Het-1A cell line was treated with pH4 acid for 12, 24, and 48 h, there were  significant differences in TEER values between different CDDO-Me pre-stimulation groups (P＜0.05). At 24 h, with the increase of stimulus concentration, TEER values gradually increased in all groups (1, 2.5, and 5 μmol/L), and the most obvious increase was in the 5 μmol/L group (P＜0.05). At concentrations of 0.5, 1, 2.5, and 5 μmol/L, the differences between the groups were statistically significant (P＜0.05). Conclusion　Acid damages esophageal epithelial barrier function, which is related to acidity and duration of action. CDDO-Me has a protective effect on the damage of acid to esophageal epithelial barrier.

Key words: electric impedance, esophageal mucosa, gastroesophageal reflux, Het-1A cells, CDDO-Me；transepithelial electrical impedance, esophageal mucosal epithelial barrier