Chronic restraint stress reduces esophageal expression of anti-oxidant proteins. Immunostaining of (A) Nrf-2 and (B) HO-1 in esophageal tissue from mice in the chronic restraint stress and control groups (magnification, ×200; scale bar. 50 µm). Quantification of the (C) Nrf-2 and (D) HO-1 positive areas. The relative mRNA expression of (E) Nrf-2 and (F) HO-1 was determined by reverse transcription-quantitative PCR in esophageal tissue from mice in the chronic restraint stress and control groups. The relative protein expression of Keap-1, p-Nrf-2, Nrf-2 and HO-1 in the (G) nucleus and (H) cytosol fractions were determined by western blot analysis in esophageal tissue from mice in the chronic restraint stress and control groups. Data presented as the mean ± standard deviation (n=15). **P<0.001 vs. control. Keap1, Kelch like ECH associated protein 1; Nrf-2, nuclear factor erythroid 2-related factor 2; p-, phosphorylated; HO-1, heme oxygenase 1.