Changes of electric activity of mesenteric nerve in guinea pig model with post-infectious irritable bowel syndrome / 中华消化杂志

ABSTRACT

Objective To investigate the changes of spontaneous activity of mesenteric nerve in guinea pig model with post-infectious irritable bowel syndrome (PI-IBS)and the response of mesenteric nerve to pressure and acid stimulation in order to clarify whether mesenteric nerve involves in the pathogenesis of the PI-IBS.Methods A total of 20 female adult guinea pigs were divided into PI-IBS group and control group,ten in each group.Guinea pigs of PI-IBS group were gastric lavaged with 8 000 to 10 000 Trichinella spiralis larves at a time,and were fed for six to eight weeks to establish PI-IBS model.The sample of proximal jejunum was taken and mesenteric nerves of guinea pigs of both groups were isolated.Spontaneous activity of mesenteric nerve was recorded in PI-IBS and control groups by extracellular electrophysiological recorder.The changes of mesenteric nerve activity were recorded after the intestine of two groups was stimulated with different dilation pressure (5 ,10,20 and 30 cmH2 O, 1 cmH2 O=0.098 kPa)and different concentration of hydrochloric acid (HCl)solution (1 ,10,20 and 30 mmol/L).Unpaired t test was performed for the comparison between the two groups.Results The spontaneous discharge frequency of mesenteric nerve of PI-IBS group was (75 .98±14.01)Hz,while that of control group was (31 .36±4.71)Hz,which was,obviously lower than that of PI-IBS group (t =9.55 ,P <0.01).After the intestine of PI-IBS group was dilated with 5 ,10,20 and 30 cmH2 O pressure, the discharge frequency of mesenteric nerve increased by (36.21±12.41)Hz,(40.18±10.48)Hz,(45.72± 10.11)Hz,and (56.05 ±9.27)Hz than baseline,respectively;likewise,in control group,after dilated with same pressure,the discharge frequency increased by (20.00±5.28)Hz,(22.13 ±3.34)Hz,(28.55 ± 4.80)Hz and (35 .07±7.56)Hz than baseline,respectively,which were significantly lower than those of PI-IBS group (t=3.80,3.19,4.85 and 5 .55 ,P =0.028,0.006,0.009 and 0.003).After the intestin of PI-IBS group was stimulated with 1 ,10,20 and 30 mmol/L HCl,the discharge frequency of mesenteric nerve increased by (2.10±0.89 )Hz,(10.87 ±3.30 )Hz,(19.59 ±2.99 )Hz and (34.49 ±6.80)Hz after stimulation respectively,while in control group after stimulated with same concentrations of HCl, the discharge frequency increased by (0.26 ±0.21 )Hz,(5 .55 ±3.91 )Hz,(7.70 ±2.53)Hz,(14.90± 10.10)Hz,respectively,which were significantly lower than those of PI-IBS group (t=6.36,3.29,9.60 and 5.09;P =0.002,0.049,<0.01 and 0.005).Conclusion The spontaneous electric activity of mesenteric nerve of PI-IBS guinea pig model increased and was more sensitive to pressure and acid,which indicated that hypersensitivity of mesenteric nerve might play an important role in the pathogenesis of PI-IBS.