The Changes Of NOS Immunoreactive Neurons, VIP Immunoreactive Neurons, ChAT Immunoreactive Neurons And SP Immunoreactive Neurons Of Colonic Submucous Ganglia In Rats With Severe Acute Pancreatitis Complicated By Gastrointestinal Dysmotility

Object: To investigate the changes of nitric oxide synthase (NOS)immunoreactive neurons， vasoactive intestinal peptide （VIP）immunoreactiveneurons，choline acetyl transferase (ChAT) immunoreactive neurons，substanceP (SP)immunoreactive neurons in colonic submucous ganglia in enteric nervoussystem (ENS)of rats with severe acute pancreatitis (SAP) complicated bygastrointestinal dysmotility. Methods:Twenty Sprague Dawley rats wererandomly divided into two groups: sham operated group (n=10)and SAPgroup(n=13). The SAP model was made by retrograde injection of5%sodiumtaurocholate into biliopancreatic duct of rat through duodenal wall. In shamoperated group, the duodenum and pancreas were only flapped several times andthen abdominal cavity was closed. Small intestinal transit index was obtained bygavaging gastrically with trypan blue.24h after the operation, rats weresacrificed. Stools were collected, weighed and dried in order to get stool watercontent. Pancreas and colon were collected for HE staining and pathological evaluation. Frequency of colonic peristalsis in virto was measured.Whole-mount preparation of colonic submucous ganglia was prepared anddouble immunofluorescence was employed to observe and calculate thepercentage of NOS immunoreactive neurons, VIP immunoreactive neurons,ChAT immunoreactive neurons and SP immunoreactive neurons in colonicsubmucous ganglia. The correlation analysis between the frequency of colonicperistalsis and the score of pancreas lesion and the percentage ofNOS/VIP/ChAT/SP immunoreactive neurons were made. Results: Comparedwith sham operated group, small intestinal transit index, frequency of colonicperistalsis, water of content of fecal matter were significantly lower (0.41±0.04vs0.14±0.02, P<0.01;13.4±1.35vs3.9±0.88, P<0.01;0.42±0.07vs0.14±0.08,P<0.01) in the SAP group. The score of pancreatic lesion was higher (1.2±0.63vs15.5±1.72，P<0.01). And a significant negative correlation was observedbetween the frequency of colonic peristalsis and score of pancreas lesion. Thepercentages of VIP immunoreactive neurons was significantly higher(14.54±2.30%vs41.04±4.36%, P<0.01) and the percentages of ChATimmunoreactive neurons was lower (43.85±13.58%vs16.27±6.97%, P<0.05).However, there was no significant changes in NOS immunoreactive neurons（22.49±5.14%vs26.36±2.57%，P>0.05）and SP immunoreactive neurons（8.54±4.47%vs5.56±3.15%，P>0.05). Correlation analysis showed that therewere irrelevant between NOS/SP immunoreactive neurons and the frequency ofcolonic peristalsis. And there was a positive correlation between frequency ofcolonic peristalsis and ChAT immunoreactive neurons (r=0.728， P<0.01).Negative correlation was observed between frequency of colonic peristalsisand VIP immunoreactive neurons (r=-0.575，P<0.05). Conclusion：Severe acutepancreatitis rats complicated by gastrointestinal dysmotility express decreased transit index of small intestine, and slowed frequency of colonic peristalsis. Theseverity of gastrointestinal dysmotility is related to the pathological changes ofpancreas. The mechanism of underlying gastrointestinal dysmotility may berelated with the plasticity of VIP immunoreactive neurons and ChATimmunoreactive neurons, leading to an increased VIP and reduced acetylcholine.A breaking balance between excitatory neurotransmitters and inhibitoryneurotransmitter and gastrointestinal dysmotility may be results.