| Severe acute pancreatitis (SAP) is a common clinical severe acuteabdomen with an acute onset, rapid progression and complexcomplications.Except edema, hemorrhage, necrosis of pancreas, it is oftenaccompanied by other viscera dysfunction, clarifying the pathogenesis ofSAP is of great significance. Studies have shown that,the physiological andpathological changes mediated by the intestinal mucosa barrier damage inSAP which cause infection, abdominal cavity effusion, abscess formation,induce and aggravate the systemic inflammatory response syndrome(SIRS),multiple organ dysfunction syndrome (MODS)played a very criticalrole in the process and even lead to the death of the patient..Autophagy, referred to as type II apoptosis,attracts lots of concern inrecent years, several studies have confirmed that autophagy is associatedwith many diseases, but there are few researches on the role of autophagy inthe intestinal mucosa barrier, The expression of autophagy in intestinalmucosal barrier has been found, but the mechanism and function remains tobe further explored.We established the model of SAP and observedautophagy expression in intestinal mucosa.We used pyrrolidine dithiocarbamate(PDTC),namely nuclear factor kappa B(NF-κB) predominateinhibitors to explore the effect of NF-κB signaling pathways in theregulation of autophagy in intestinal mucosa,and new molecularmechanisms of intestinal mucosa barrier damage in SAP.We tried to providenew treatment strategies for the treatment of SAP.Objective: To observe the expression and effect of autophagy in theintestinal mucosa of rats with SAP induced by L-arginine intraperitonealinjection.Methods:120clean adult SD rats with average weight of250±30g, were randomly divided into normal control group (N), the model of severeacute pancreatitis (SAP) group and PDTC group.According to the dosage,PDTC group were divided into1mg/kg (P1),10mg/kg (P10) and100mg/kg(P100) groups.Each group was divided into12hours and24hourssubgroups.There was12rats in each group. Before the experiment, toinduce SAP model, rats were fasted for12h and water was given, twiceintraperitoneal20%L-arginine injection was given,2.5g/kg each time withinterval of1hour.1hour before the SAP model was established, PDTCgroups were given1mg/kg,10mg/kg and100mg/kg PDTC intraperitonealinjection; The control groups were injected with equal volume of0.9%sodium chloride. Rats were killed12h or24h later, serum,pancreas andsmall intestine tissue were collected.The pancreatic tissue and small intestine tissue was observed bymicroscope, The content of LC3and Beclin1protein,NF-κB p65proteinwere detected by Western blot. Intestinal tissue homogenate was used forthe determination of superoxide dismutase (SOD) and malondialdehyde(MDA) content, ELISA was applied to detect serum intestinal fatty acidbinding protein (I-FABP).Results:1The pathobiology changes of pancreatic tissue: In thecontrol group, pancreatic tissue structure complete, gland flocculus andglands visible, no bleeding and necrosis, there was no difference in the twotime points. In SAP group:Pancreatic interlobular edema, acinar cellvacuolar degeneration, wide infiltration of inflammatory cell in intralobular,patchy necrosis and hemorrhage. We found that changes in24h subgroupswere more serious than the12h subgroups.The intervention group (P1, P10,P100): each group showed relatively obvious inflammatory changes, TheP100groups were the most serious, visible diffuse acinar cell necrosis, partof acinus like an island, pancreatic inflammation significantly reduced inP10and P1groups.2The pathobiology changes of intestinal tissue: In the controlgroup,the intestinal villi arranged in neat rows, the epithelial cell layer intact, brush border was smooth, no significant sigh of inflammation.Therewas no significant difference between24h group and12h group.However,in SAP groupdegeneration, necrosis, partial nudity shedding even in thelamina propria could be found in the intestinal mucosal epithelial cells,intestinal villi became shorter, disorganized,small intestinal lamina propriainfiltration of neutrophils, blood capillary dilate, hyperaemia. The intestinalmucosal damage at24h subgroups were more serious than the12hgroups.Among the whole PDTC groups the degree of intestinalinflammatory injury of P100group were the most serious, P1and P10groups’ mucosal damage were ruduced compared to P100groups and SAPgroups.3The expression of serum I-FABP: I-FABP in SAP group significantlyelevated than that in the normal group both at12h’s and24h’s. After theintervention, notable decrease was found compared with SAP group,but stillhigher than control group (P <0.05). P100group was similar to that in SAPgroup(P>0.05).At12h,there’s no significant diffence between P1and p10group,but at24h,the expression of serum I-FABP in P10group was lowerthan that in P1group.SAP and P1group at24h increased significantlycompared with that of12h(P <0.05),The rest three groups had nosignificant difference in different time points (P>0.05).4The expression of Beclin1protein small intestine:SAP group wasevidently higher than control group(P <0.05), P1,P10group clearlydecreased compared with SAP group(P <0.05). At12h,P100group has nosignificant diffence with SAP group,while higher at24h. Beclin1in P100group at24h increased significantly than that at12h (P <0.05).5The expression of LC3protein in small intestine: Compared withcontrol group, LC3of SAP group in12h and24h significantly increased (P<0.05).After PDTC pretreatment, both in the12h and24h group, P1andP10group’s expression reduced compared with SAP group (P <0.05),whereas P100group’s LC3protein expression increased significantlycompared with SAP (P <0.05), P1and P10groups at the same time has no significant difference (P>0.05); Except control group,the other fourgroups’ LC3protein expression increased at24h (P <0.05).6The expression of NF-κB p65protein in small intestine:SAP groupwas obviously higher than that of control group at both12h and24h(P <0.05). P1,P10group notable decreased compared with SAP group (P <0.05), but higher than control group (P <0.05), P100group group has nosignificant difference compared with SAP group (P>0.05), P10group waslower than those of P1group (P <0.05); SAP,P1and P100groups at24hincreased compared with that at12h (P <0.05),.The control group and P10group had no difference between the two time points (P>0.05).7Changes of MDA in small intestinal homogenate:SAP group wasevidently higher than control group, P1,P10groups clearly decreasedcompared with SAP group, control group was the lowest(P <0.05); SAPand P100group had no notable difference(P>0.05), P1and P10group hadno significant differences in the results of the12h group. P1group at24hourwas higher than P10group at24hour;Compared12h with24h group,SAP,P100,P1groups at24h were higher than12h, while P1and contrlol groupshad no significant differences (P>0.05).8Changes of SOD insmall intestinal homogenate: at two time points,the SAP group were significantly lower than the control group (P <0.05),P100group was lower than those of SAP group at12h,P10group hasimproved(P <0.05), P1group was not different from that in SAP group(P>0.05),; At24h, SAP, P100groups continued to decrease, P10groupcontinues to improve, P1group had no significant change (P>0.05).Conclusion:1Intraperitoneal injection of L-arginine cansuccessfully establish severe acute pancreatitis model and form theintestinal mucosa barrier damage at the same time.2A moderate amount of NF-κB inhibitors PDTC intervention helpspromote acute pancreatitis and intestinal mucosal barrier function recovery.3The expression of autophagy protein Beclin1and LC3in smallintestine tissue of acute pancreatitis increase, the expression level is associated with damage drgee of intestinal mucosa.4The NF-κB signaling pathway may be involved in regulation ofintestinal mucosa autophagy, inhibition NF-κB lead to inhibition ofautophagy.5Reactive oxygen species may induce autophagy formation. |
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