| Objective: To investigate the relationship between colonic H2S-producing enzyme CSE and colonic motility in a rat model of diabetes mellitus. Methods:50 rats were randomly divided into 2 groups: the NC group（n=10） and DM group（n=40）. The DM rats were modelled by intraperitoneal injection of streptozotocin（STZ, 65mg/kg）. After 10 days of injection, 10 DM rats and 10 NC rats were sacrificed for basic analysis. The other 30 DM rats were further divided into 3 groups: the DM + blank group（without further injection）, the DM+NS group（9%NS 50ml/Kg.d）, and the DM+PAG group（PAG 50mg/Kg.d）,for 15 days. Samples from all the rats were tested for: the organ bath recordings to test the colonic motility of colonic longitudinal smooth muscle;immunohistochemistry and double immunofluorescence lableling method were performed to detect the distribution of CSE; Western blot was performed to detect the expression of CSE on rat colonic samples that devoid of mucosa and submucosa. Results: The colonic motility in the DM rats were decreased compared with that in the rats of NC group（p < 0.05）, and the colonic motility in the rats of DM+PAG group were increased compared with those in the rats ofDM+NS group and the DM+blank group（p < 0.05）. CSE was strongly expressed in the cytosols of the circular and longitudinal smooth muscle cells and the nucleus of the myenteric plexus neurons. The expression of CSE was increased on DM rat colonic samples that devoid of mucosa and submucosa（p <0.05）. The expression of CSE was decreased on DM+PAG rats compared to the DM+NS group and the DM+blank group in the colonic samples that devoid of mucosa and submucosa（p < 0.05）. There was a negative correlation between the AUC and the expression of CSE in our study（p < 0.05）. Conclusion: The decreased colonic motility of DM rat may be significantly associated with the increased production of H2S-producing enzyme. |
