| Objective To establish rat model of irritable bowel syndrome,observe the expression of glial cell line-derived neurotrophic factor which is GDNF gene encoding produce in colonic myenteric plexus of rat model of IBS,and the changes of neurons in colonic myenteric plexus,preliminary to study on the correlation between them and both of the role in the pathogenesis of IBS.Methods 45 male SD rats were randomly divided into IBS1 (acetic acid enema) group,IBS2 (chronic anger) group and control group,n = 15.using the metheds of acetic acid enema and chronic anger to establish rat model of IBS,then used measurement of abdominal muscle activity and detection of colonic transport function to evaluate the models.Observed the expression of colon myenteric plexus neurons which were marked by cathepsin-D protein,and detected the expression of GDNF protein in colon myenteric plcxus of rat model,and the correlation between them.Results⑴The number of electrical activity of external oblique in IBS1 group under different expansions of capacity was significant higher than the control group (P <0.05). The time of the ball discharged by rectal in IBS2 group was significant less than the control group (P <0.05),and the number of fecal discharged in unit time was significant higher than the control group (P <0.05).In histological examination,all the rats'intestinal mucosa had integrated structure without hyperemia,edema,ulcers and the changes of infiltration by inflammatory cells observed with a microscope.⑵The number of neurons in IBS1 group was significantly less than the control group (P <0.05),compared the number of neurons in IBS2 group with the control group,the difference between the two groups was not significant (P> 0.05).⑶Expression of GDNF in colonic myenteric plexus in IBS1 group was significantly higher than the the control group(P <0.05),compared IBS2 group with the control group,there was no difference between the two groups statistically significant (P> 0.05).⑷CAD was negatively correlated with GDNF.Conclusions⑴Rat model of IBS made by the method of acetic acid enema made consistent with the mechanism of visceral hypersensitivity of IBS. Rat model of IBS made by the method of chronic anger made consistent with the mechanism of gastrointestinal motility of IBS,both of them can be used as successful animal models for the experimental study of IBS.⑵There was neuronal plasticity in colonic myenteric plexus of rat model of IBS made by the method of acetic acid enema but was not by chronic anger. Speculated that neuronal plasticity may be one of the reasons which is infected with IBS (PI-IBS) in the pathogenesis.⑶Injured neurons increase demands for GDNF,indicating that GDNF could maintain the role of neurons in the gastrointestinal tract. |
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