Effects Of Abdominal Paracentesis Drainage On Gastrointestinal Motility Of Severe Acute Pancreatitis Rats And Its Mechanism

objective: In the previous studies,a stable and efficient model of rats with severe acute pancreatitis induced gastrointestinal dysfunction was established by retrograde pancreatic duct injection of 5% sodium taurocholate,and we combined with clinical practice to explore the treatme nt model of abdominal paracentesis drainage for rats.On the basis of this study,the effects of abdominal paracentesis drainage on gastrointestinal motility of severe acute pancreatitis rats and its Mechanism were discus sed.Methods : The models of SAP rats with gastrointestinal dysfunction were induced by retrograde injection of 5% sodium taurocholate into the cannulated biliopancreatic duct through a micro infusion pump.For intes tinal transit test,1.5 ml of 10g/L trypan blue solution was intragastrically gavaged for each rat.30 min later,rats were sacrificed,and then the ra tio of small intestine trypan blue forward distance and small intestine length was measured.Part 1,thirty male SD rats with SAP were randomly divided into three groups:6 hours group(n=10),12 hours group(n=10),24 hours group(n=10).And then the point-in-time whose small intestinal tran sit index was the lowest in the three groups through intestinal transit test showed the probable time of gastrointestinal motivation was the weakest after SAP model rats were established successfully.Part 2,30 SPF male SD rats were casually splited into 3 groups,10 rats in each group: sh am group(sham group): The rats were anesthetized and open the abdomi nal cavity,and the abdomen was closed after turning the pancreas several times.Severe acute pancreatitis group(SAP group): the SAP rat with gastrointestinal dysfunction models were induced as above.Abdominal para centesis drainage group(APD group): On the basis of the establishment of the rat model suffered from severe acute pancreatitis with gastrointestinal dysfunction,a special cruciate flower drainage tube was put in the abdominal cavity of rats to drainage of ascites produced by the SAP rat.According to the results of the first part,small intestine propulsion test was performed at 24 hours after the SAP rats were modeled successfully.30 min later,the condition of abdominal cavity was observed through a nesthesia laparotomy,and then bdominal aortic blood was collected to kill rats.We measured small intestinal transit index,and pancreas,ileum tis sue(beginning at 5 cm orally to the ileocecal orifice),and ascites sampl es were collected.Pathological changes in pancreas were detected by HE staining;The serum levels of tumor necrosis factor-α(TNF-α),interleuki n-1(IL-1β),motilin(MTL),cholecystokinin(CCK),α-amylase was assayed via iodine-starch colorimetric,and ascitesand vasoactive intestinal pep tide(VIP)were determined by ELISA;The contents of nitric oxide conte nt in serum were measured by Nitrate reductive enzymatic;Immunohistoc hemistry assessed neuronal nitric oxide synthase(n NOS)expression in ileal tissue.Neuronal NOS m RNA expression was evaluated by RT-PCR.Part 3.Because it was a long time for determining ileum myoelectricity a fter successful building 24 hours,and this would leaded to additional int ervention for small intestine propulsion test and specimen collection,so we choosed 30 SPF male SD rats and we put them splited into 3 group s randomly,10 rats in each group: sham group;SAP group and APD gr oup.After Successful building 24 hours,rats were narcotized by injecting 4% chloral hydrate into abdominal cavity.And then,BL-420-F biological function experiment system determined the ileum electromyography of every rat.Results: Comparing the index of small intestine propulsion at different time points,we found the slowest of the small intestine propulsion was 24 hours after the success of SAP rats building.The rat in Sham group did not produce ascites,but SAP group had,and a large number of amylase,TNF-α and IL-1β were detected in the ascites.Compared w ith the sham operated group,pathological score of pancreatic tissue were more marked,and the serum amylase,IL-1β,TNF-α and VIP were observably higher in SAP group and APD group,(the discrepancy was stat istically meaningful,P<0.05),however,small intestine propulsion index,MTL and CCK were observably lower,(the discrepancy was statistically meaningful,P<0.05);In addition,average slow wave frequency(brats per min)and amplitude(m V)of ileum myoelectricity reduced in SAP gro up and APD group(the discrepancy was statistically meaningful,P<0.05);NO content of rat serum,n NOS and nNOS-m RNA expression in ileum of SAP group and APD group were observably higher than that in the sham operated group,(the discrepancy was statistically meaningful,P<0.05).Compared with the rats in the severe acute pancreatitis group,patholo gical score of pancreatic tissue in APD group was more lower,and the serum amylase,IL-1β,TNF-α and VIP were observably lower in APD g roup,(the difference was statistically significant,P<0.05),however,sma ll intestine propulsion index,MTL and CCK were observably higher,(the discrepancy was statistically meaningful,P<0.05);In addition,average slow wave frequency(brats per min)of ileum myoelectricity increaced in APD group(P<0.05),but amplitude(m V)had no observably difference(P>0.05);NO content of rat serum,nNOS and n NOS-m RNA expression in i leum of APD group were observably lower than that in the SAP group,(the discrepancy was statistically meaningful,P<0.05),and the disease outcomes was better.conclusion: Abdominal paracentesis drainage could accelerate intestinal muscle activity,and maybe the reason was the content of neurotransmitter NO reduced through reducing the expression of nNOS in the intestinal tissue.Thus,it improve the gastrointestinal motility dis turbance of SAP rats.