Effect and mechanism study on transcutaneous auricular vagus nerve stimulation for functional dyspepsia model rats

Objective:To explore the effect and its possible mechanism of the intervention of transcutaneous auricular vagus nerve stimulation(taVNS)for the functional dyspepsia(FD)model rats.Methods:Of the 25 male SD rats,6 rats were set as blank group,the other 19 rats were established to be the functional dyspepsia(FD)model by iodoacetamide intragastric administration,and 18 FD models were successfully established.The 18 model rats were randomly divided into a model group,a shamtaVNS group,and taVNS group,with 6 rats in each group.There was no intervention applied to the rats in the blank and model groups.Whereas,the rats in sham-taVNS group received stimulation to the rim of auricular concha of both sides,and those in taVNS group received stimulation to the cavity of auricular concha of both sides,for 30 min each time,once a day,7 days in succession.After the intervention,the gastric sensitivity of the rats in each group under different pressure conditions in the stomach,the expressions of serum brain-gut peptide motilin(MTL),cholecystokinin(CCK),glucagon-likepeptidel(GLP-1),and inflammatory factors IL-4,IL-10,and IL-1βwere detected.Results:(1)Gastric sensitivity:compared with the blank group,the gastric sensitivity of the model group was higher(P<0.05).Compared with the model group,the gastric sensitivity of the taVNS group was lower(P<0.05).Compared with the sham-taVNS group,the gastric sensitivity of the taVNS group was lower(P<0.05).(2)Expression of brain-gut peptide:compared with the blank group,MTL was lower,CCK and GLP-1 were higher in the model group(all P<0.05).Compared with the model group,MTL was higher,CCK and GLP-1 were lower in the taVNS group(all P<0.05).Compared with the shamtaVNS group,CCK and GLP-1 were lower in the taVNS group(both P<0.05).(3)Expression of inflammatory factors:compared with the blank group,IL-4 and IL-10 were lower and was higher in the model group(all P<0.05).Compared with the model group,IL-10 was higher and IL-1βwas lower in the shamtaVNS group(all P<0.05),while IL-4 and IL-10 were higher and IL-1βwas lower in the taVNS group(all P<0.05).Compared with the sham-taVNS group,IL-4 and IL-10 were higher and IL-1βwas lower in the taVNS group(all P<0.05).Conclusion:TaVNS can reduce the gastric sensitivity of FD model rats by peripheral anti-inflammatory action and regulating the abnormal secretion of brain-gut peptide.