The Change Of Nitric Oxide Synthase Neurons In Enteric Nervous System In Severe Acute Pancreatitis Rat

Objective To explore the nervous mechanism of gastrointestinal dysmotility in severe acute pancreatitis(SAP) rat, by observing the change of nitric oxide synthase(NOS) neurons in enteric nervous system (ENS).Methods 20 Sprague Dawley rats were randomly divided into sham operation group and SAP group. SAP model was induced by retrograde cholangiopancreatic duck injection with 5% sodium taurocholate. Abdominal X-ray, small intestinal transit index, pathological score of pancreas were detected. Double-immunofluorescent stain was employed for myenteric plexus whole-mount preparations and submucosal plexus preparations of intestine. The morphology of NOS neurons was observed and the percentage of NOS neurons was calculated based on the total neurons of Hu-immunoreactivity. Total RNA of intestine was extracted according to Trizol reagent protocol, mRNA expression of neuronal NOS (nNOS) was evaluated by RT-PCR.Results Compared with sham operation group, intestine significantly expanded, small intestinal transit index was significantly lower (P<0.01),the pathological score of pancreas was significantly higher(P<0.01)in SAP group. In ileal and colonic myenteric plexus, NOS neurons of were bigger and more deeply stained, NOS nerve fibers between ganglions were thicker in SAP group than those in sham operation group. The percentages of NOS neurons in ileal and colonic myenteric plexus in SAP group were(37.32±3.97)% and (40.74±5.15)%, significantly higher than those in sham operation group(P<0.01). The percentage of NOS neurons in colonic submucosal plexus in SAP group was not significantly higher than that in sham operation group(P>0.01). mRNA expressions of nNOS in ileum and colon in SAP group were(1.02±0.10)and (1.24±0.28) , significantly higher than those in sham operation group(P<0.01).Conclusions The increased quantity of NOS neurons and increased nNOS mRNA expression in myenteric plexus in ileum and colon may suggest that nNOS over expression is one of the nervous mechanisms of gastrointestinal dysmotility in SAP rat.