| PartⅠChange of the Mesenteric afferent nerve electric activity in the PI-IBS guinea pig modelObjective To study the electric activity changes of mesenteric afferent nerve in the guinea pigs infected with trichina spiralis in different periods and to study the response of the mesenteric afferent nerve of the guinea pigs infected with trichina spiralis in chronic infection stage. To identify whether the mesenteric afferent nerve involve the pathophysiology process of the post-infectious irritable syndrome and the mechanisms.Methods Forty female guinea pigs were randomly divided into control group, acute infection group and chronic infection group. The control group was 20 guinea pigs and the other two group was 10 guinea pigs respectively. After one week adaptive feeding, the acute group and chronic group were orally administered 0.2ml PBS with 8000 Trichinella Spiralis larvae and the control group was orally administered 0.2ml PBS. In different periods, the guinea pigs were sacrificed. Segments of proximal jejunum,3-5cm long, were harvested and placed into a Sylgard-lined organ chamber (20ml) which was continually superfused with Krebs solution gassed with carbogen (95%O2,5%CO2) at a flow rate of 10ml min-1. The mesenteric bundle was pinned out to the base of the chamber and a mesenteric nerve was dissected out from the bundle under dissecting microscope. Extracellular multi-unit mesenteric afferent nerve recordings were obtained in the proximal jejunum from the different groups. The discharge frequency was recorded in the control group and chronic infection group after the bowels were treated with different pressure distension(0cmH2O,5cmH2O, 10cmH2O,20cmH2O,30cmH2O,0cmH2O) and different concentration hydrochloric acid perfusion (0mM,1mM,10mM,20mM,30mM).Results (1)The average discharge frequency was 10.48±3.89 Hz in the acute infection group, which was significantly lower than that in the control group(31.36±4.71 Hz, p<0.001) and the discharge amplitude in the acute infection group was also decreased compared with the control group. However, the average discharge frequency in the chronic group was 75.98±14.01 Hz, which was obviously higher than that in the control group and acute group(p<0.001,p<0.001) and the discharge amplitude was also increased compared with the other tow groups. (2) The average discharge frequency in the chronic group was 63.39±4.56Hz,93.6±23.18Hz, 92.56±13.38Hz,107.11±15.26Hz,107.44±21.83Hz,112.79±20.85Hz after different pressure distension respectively (0cmH2O,5cmH2O,10cmH2O,20cmH2O, 30cmH2O,40cmH2O), which was significantly higher than that in the control group (32.86±3.73Hz,52.86±3.2Hz,49.99±3.9Hz,56.22±7.19Hz,67.57±4.53Hz, 52.38±9.86Hz,p<0.01). (3) The average mesenteric nerve discharge frequency in the chronic group was 66.28±6.96Hz,68.38±8.17Hz,77.23±9.88Hz,85.95±6.48Hz, 101.75±10.9Hz after different concentration acid perfusion respectively (0mM, 1mM, 10 mM,20mM,30mM), which were obviously higher than that in the control group(33.99±8.95Hz,34.25±7.64Hz,40.14±6.69Hz,41.65±3.63Hz,48.96±11.77Hz,p<0.01).Conclusion The increased spontaneous electric activity and more sensitive to the pressure and acid stimulation in the mesenteric afferent nerve in the PI-IBS guinea pig model may have an important role in the visceral hypersensitivity formation in the PI-IBS.Part II Effect of intestinal mucosa extract from the PI-IBS animal model to the mesenteric afferent nerve electric activityObjective:To investigate the effect of intestinal mucosa extract from the PI-IBS animal model to the mesenteric afferent nerve electric activity and the role of mast cell in this effect.To identify the action of the secretions from intestinal mucosa of the PI-IBS animals to the mesenteric afferent nerve.Methods:Twenty female guinea pigs were randomly divided into two groups, which were control intestinal mucosa extract group and chronic infection intestinal mucosa extract group with different location. The chronic infection intestinal mucosa extract group was divided into two subgroups which were without sodium cromoglicate treatment group and pretreatment with sodium cromoglicate group. After one week adaptive feeding, the chronic group were orally administered 0.2ml PBS with 8000 Trichinella Spiralis larvae and the control group was orally administered 0.2ml PBS. In the eighth week after Trichinella Spiralis infection, the animals were sacrificed. The intestinal mucosa secretions were got from the ileum, proximal colon and distal colon of different groups. In the chronic infection group pretreatment with sodium cromoglicate, the intestinal mucosa was incubated with Krebs solution containing 1mg/ml sodium cromoglicate and then the secretions were got. Then the intestinal mucosa extract supernatant from different groups were perfused into the normal guinea pigs proximal jejunum and the afferent nerve activity was recorded using extracellular multi-unit recorder after perfusion.Results (1)The average discharge frequency after perfused with intestinal mucosa extract supernatant from the ileum, proximal colon and distal colon of the chronic infection group was 41.01±7.6 Hz,45.9±11.2 Hz and 48.25±9.7 Hz respectively, which was apparently higher than the baseline discharge frequency before perfusion(24.24±7.0Hz,p= 0.001,25±9.35Hz,p<0.001,25.43±7.6Hz,p<0.001)and higher than that from the control group(p=0.001,p=0.002,p<0.001). The afferent discharge frequency after perfused with intestinal mucosa extracts from the ileum, proximal colon and distal colon of the control group was 26.55±0.67Hz,30.88±6.92Hz and 29.47±6.13Hz respectively, which was no difference compared with the baseline before perfusion (25.93±2.37Hz,p= 0.666,27.25±6.97Hz,p= 0.417,28.18±6.71 Hz,p=0.694). (2) The average discharge frequency after perfused with intestinal mucosa extract supernatant from ileum, proximal colon and distal colon of the chronic infection group pretreatment with sodium cromoglicate was 32.71±2.52Hz,30.94±4.44Hz and 7.51±5.83Hz respectively. Compared with baseline before perfusion, the discharge frequency in the ileum and proximal colon group pretreatment with sodium cromoglicate increased somewhat (25.98±1.42Hz,p= 0.015; 26.14±2.15Hz,p= 0.01). However, the distal colon intestinal mucosa extract pretreatment with sodium cromoglicate had no difference compared with the baseline before perfusion (26.75±1.18Hz,p=0.722). Compared with chronic infection group without sodium cromoglicate treatment, the average discharge frequency after perfused with the ileum, proximal colon and distal colon intestinal mucosa extract pretreatment with sodium cromoglicate was significantly reduced (p=0.03,p= 0.002, p<0.001).Conclusion The intestinal mucosa extracts from the PI-IBS animal model can excite the mesenteric afferent nerve and may involve the pathophysiology process of the PI-IBS. In that process, the secretions from the mast cells may have an important role, and other factors also involve that process. PartⅢEffect of intestinal mucosa extract from the PI-IBS patients to the mesenteric afferent nerve electric activityObjective:To investigate the effect of intestinal mucosa extract from the PI-IBS and non-PI-IBS patients to the mesenteric afferent nerve electric activity and identify the action of the secretions from the intestinal mucosa of PI-IBS patients to the mesenteric afferent nerve.Methods:The intestinal mucosa extracts were got from post-infectious irritable bowel syndrome (PI-IBS) patients, non-PI-IBS patients and ten healthy volunteers who were biopsied in the rectum-sigmoid juncture. Then the intestinal mucosa secretions from different groups were got and perfused into the normal guinea pigs proximal jejunum and the afferent nerve electric activity was recorded using extracellular multi-unit recorder.Results (1) The average discharge frequency after perfused with intestinal mucosa extracts from PI-IBS patients was 54.96±14.49 Hz, which was significantly higher than the baseline before perfusion(26.59±2.1Hz, p<0.001), however, the average discharge frequency from the healthy volunteers was 32.37±4.89 Hz,which had no difference compared with the baseline before perfusion(30.24±2.62Hz, p=0.091). The intestinal mucosa extracts from PI-IBS patients obviously increased the mesenteric nerve discharge frequency compared with healthy volunteers (54.96±14.49Hz Vs.32.37±4.89 Hz,p<0.001). (2) The afferent discharge frequency after perfused with intestinal mucosa extracts from non-PI-IBS patients was56.79±19.11Hz, which was significantly higher than that from healthy volunteers(32.37±4.89 Hz, p<0.001), however, there was no difference between the PI-IBS patients and the non-PI-IBS patients(54.96±14.49Hz Vs.56.79±19.11Hz, p=0.66).(3) The average discharge frequency after perfused with intestinal mucosa extracts of the IBS patients who had abnormal defecation process such as sense of urgency was 66.03±12.6 Hz, which was significant higher than that who didn’t have abnormal defecation process (52.57±11.8Hz,p=0.045). In addition, the average discharge frequency in the patients who exceeded one year was 58.26±18.81 Hz, which was higher than that who didn’t exceed 1 years, but statistics have no significance(49.37±10.84Hz, p=0.09). There was no relationship between the discharge frequency after perfused with intestinal mucosa extract and the sex, smoking, alcohol consumption, body mass index, somnipathy, number of the defecation, abdominal distension of the patients(all p>0.05).Conclusion The intestinal mucosa extracts from PI-IBS and non-PI-IBS patiens can obviously excite the mesenteric afferent nerve, which indicate that the cross-talk between the mesenteric afferent nerve and intestinal mucosa may participate the pathophysiology process of the IBS. |
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