Relation between esophageal visceral hyperesthesia and expression of acid-sensing ion channel 1 in rats with reflux esophagitis / 中华消化杂志

ABSTRACT

Objective To explore the role of the visceral afferent nerve hyperesthesia and acid-sensing ion channel 1 (ASIC1) in rats with reflux esophagitis (RE).Methods Sixty male Sprague-Dawley rats were selected and animal model was established.Rats were divided into control group (n=20) and RE group (n=40).The esophageal mocosa biopsy were routinely performed in two groups.The esophageal specific DRG neurons were identified by 1,1'dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate tracing method and the whole-cell patch clamp assay was performed.The expression of ASIC1 in esophageal mucosa and thoracic spine cord three to five segments at protein level and mRNA level were detected by Western blotting and quantitative real time-polymerase chain reaction (qPCR).Two independent samples t test was performed for statistical analysis.Results The body weight of RE group was significantly lower than that of control group ((179.41±-16.38) g vs (290.75 ±-22.20) g),and the difference was statistically significant (t=17.090,P＜ 0.01).Esophageal basal cell hyperplasia,papillary elongation,vascular dialation and congestion,inflammatory cells infiltration were found in RE group rats.The results of whole-cell patchclamp showed depolarization of the resting potential of esophageal-specific DRG neurons of RE group was more significant than that of control group (-(46.20 ± 1.92) mV vs-(51.60 ± 1.52) mV),and the difference was statistically significant (t=4.930,P＜0.01).The threshold current of RE group was much lower than that of control group ((18.00±13.04) pAvs (80.00±12.25) pA),and the difference was statistically significant (t=7.750,P＜0.01).When stimulated with two to three times the threshold current,the frequency of action potential of RE group significantly increased (5.80 ±1.48 vs 3.00 ±1.58,10.60±2.30 vs 5.20±1.92),and the differences were statistically significant (t=2.890 and 4.030,both P＜0.01).The results of Western blotting indicated that the expression of ASIC1 in esophageal mucosa of RE group was significatly lower than that of control group (0.614±0.120 vs 0.976±0.283),and the difference was statistically significant (t =2.885,P＜ 0.05),while there was no statistically significant difference in the expression of ASIC1 in DRG between RE group and control group (0.804 ± 0.182 vs 1.032±0.316;t=1.528,P＞0.05).The results of qPCR showed that the expression of ASIC1 mRNA in esophageal mucosa of RE group was lower than that of control group (0.694 ± 0.118 vs 1.036 ±0.137),and the difference was statistically significant (t=4.642,P＜0.01).However there was no statistically significant difference in ASIC1 at mRNA level between RE group and control group (1.002± 0.074 vs 0.985±0.120;t=0.294,P＞0.05).Conclusion The sensitivity of esophageal visceral afferent nerve of rats in RE group increases and ASIC1 may negatively regulate the formation of esophageal visceral hypersensitivity.