The expression of NADPH oxidase-4 and acid sensitive receptors in the esophagus of chronic restraint mice / 中国医师杂志

ABSTRACT

Objective:To investigate the chronic restraint stress induced expressions of acid sensitive receptors and its role in the esophageal inflammation and oxidative stress.Methods:Twenty male specific pathogen free (SPF) Kunming mice were randomly divided into two groups stress group and control group (each group, n=10). Stress mice were restrained in self-made restraint device for 2 hours per day and lasted for total 14 days. The histopathological changes of esophageal mucosa were observed by hematoxylin eosin (HE) staining under light microscope. The expression of nicotinamide adenine dinucleotide phosphate (Nox-4) was detected by immunohistochemistry, real time fluorescent quantitative polymerase chain reaction (qRT-PCR) and enzyme linked immunosorbent assay (ELISA). The mRNA expressions of acid sensitive receptors were detected by qRT-PCR. Results:HE staining showed that stress mice had obvious infiltrations of neutrophils and eosinophils, and also showed inflammatory change in esophgus, while no significant abnormality was found in the esophagus of control mice. The inflammotory scores in stress group were significantly higher than that in control group ( P<0.001). Immunohistochemistry showed that Nox-4 was mainly expressed in the lamina propria, mucosa and submucosa of esophagus. The mRNA expression levels of Nox-4 in stress group was (2.67±0.62) times higher than control group, with statistically significant difference ( P<0.001). In addition, the plasma concentration of Nox-4 in stress group was significantly higher than that of control group [(0.42±0.01)ng/ml vs (2.13±0.35)ng/ml, P<0.001]. The transcription levels of acid sensitive receptors in stressed mice, such as transient receptor potential vanilloid-1 (TRPV-1), TRPV-4, acid-sensing ion channel-1 (ASIC-1), ASIC-2 and ASIC-3 were significantly higher than those in the control group, with statistically significant difference ( P<0.001). Pearson correlation analysis showed that there was a positive correlation between Nox-4 mRNA expression and TRPV-1, TRPV-4, ASIC-1, ASIC-2, ASIC-3 mRNA expression in stress group ( r=0.97, 0.94, 0.98, 0.95 and 0.99, P<0.01). Conclusions:Stress may increases the expression of acid sensitive receptors and result in an esophageal inflammation and oxidative stress, which may contribute to the formation of esophageal hypersensitivity.