Effects Of The NO On The Motility Funtion Of The Proximal Colon Of Diabetes Mellitus Mice

Colonic dysfunction is a frequent complication of diabetes mellitus(DM). Even though autonomic neuropathy, gastrointestinal hormone, vasodilation and hyperglycemia are regarded as the important factors in colonic dysfunction of DM, there are many problems without clarification.The nitric oxide (NO) signaling pathway are major nonadrenergic-noncholinergic transmitter mechanism in the enteric nervous system. NO is a Inhibitory neural transmitter on the gastrointestinal tract. We substantiated that No occur to DM and the course of chronicity complication. And we found there is a distributing of oxide synthase (NOS) in entire gastrointestinal tract of the human being and else animal. The content of neuronal (nNOS ) increases in evidence on the colon of DM rat up to the minute.But there are a fat lot news about the particular mechanism and their connection of NO,ICC in DM Colonic dysfunction. There are now direct evidences from some studies that the ICC are pacemakers in specified regions of the gut in some species and play an central role on intestine nerve signaling. Some studies acquire that the DM rat undergoes a decrease in the number of stomach ICC, and the observation of ultramicro-pathology infers the one of reasons is that decrease or the change of function of ICC induce colonic dysfunction of DM. To address this issue, thefollowing studies were designed and performed.In the first study, the distribution,expression of nNOS in the proximal colon were evaluated by immunofluorescence staining and Western-blotting. The study is to investigate the effect of nitric oxide (NO) on the isolated mouse the proximal colon muscle strips. With the control group, expression of nNOS in the proximal colon was increased in DM group (P<0.05). Compared to the controls, the proximal colon muscle strips muscular tension were easily distinguished from diabetes mellitus mice by 7-nitroindazole (7-NI )(P<0.05). l-arginine (L-arg) decreased the proximal colon muscle strips contractile amplitude(P<0.05). But, there was no changes when Amino guanidine (AG) was added. At the same time,we could not find the difference of contractive frequency in the study.In the second study, With the control group( concentration of glucose 5.5mmol/L), ICC in vitro from the proximal colon were treated with mannitol(concentration of glucose 5.5mmol/L,concentration of mannitol glucose 27.5mmol/L ) high-glucose ( concentration of glucose 33mmol/L) respectively for 24h. The morphologic changes characteristic of apoptosis were observed under light microscopy. Cells viability was tested by MTT assay. Expression and activat of nNOS were evaluated by Western-blotting. Compared to the controls, Cells with this morphology were easily distinguished from under high-glucose(P<0.05), most cells began to lost a characteristic network of each other and cells began to circular. No changes of morphological feature in the control and mannitol groups (P>0.05).The activation of nNOS was gradually reduced under hyperglycemia(P<0.05). In the meantime, no changes of nNos expression occurred in control and mannitol groups(P>0.05).Together with our stidies, we conclude that:1. This suggests that the increaseing of nNOS may play an important role in the pathogenesis of diabetic the proximal colonic dysfunction by the decreaseing of muscular tension and steadiness of contractive frequency.2. Dissociation, culture of interstitial cells of Cajal in vitro was established. Hyperglycemia could inhibit the proliferation and funtion of ICC and nNOS expression. The abnormal expression of nNOS suggests that the decreaseing of expression of nNOS because of the proliferation and funtion of ICC.3. Effects of the NO on the motility funtion of the proximal colon of diabetes mellitus mice by funtion of restraining of smooth muscle cell and the form,funtion of changing of ICC.