Mechanism Of Galantide Treats Acute Pancreatitis In Mice

Objective: To explore the effect of galanin receptor antagonist,galantide,on different timepoints inflammatory(IL-1) and anti-inflammatory(IL-10) cytokine during cerulein-induc-ed AP in mice.Matrials and Methods:One-hundred and twenty eight healthy KM male mice wererandomly divided into four groups:①control (NS) group (n=32);②acute pancreatitis(AP) group (n=32);③Galantide-treated (AP+GT) group (n=32);④Galantide control (GT)group(n=32).Each group was randomly again divided into4time points (3,6,12,24h) with8mice in each time point.Twelve hours before the start of the experiment,the mice weredeprived of food but allowde access to water. In NS group, mice were injectedintraperitoneally with normal saline repeatedly every1h (7injections in total) at a doseof10ml/kg. In AP group, mice were injected intraperitoneally with cerulein repeatedlyevery1h (7injections in total) at a dose of50μg/kg. In AP+GT group, mice wereinjected intraperitoneally with cerulein and galantide.Galantide at a dose of66μg/kg wasco-administered with each injection of cerulein(50μg/kg) commencing with the firstcerulein injection.Injection was repeatedly every1h (14injections in total). In GT group, mice were injected intraperitoneally with galantide repeatedly every1h (7injections intotal) at a dose of66μg/kg. Mice were dissected at3,6,12,24h according to therrespective time point group after the final injection under anaesthesia throughintraperitoneal injection10%chloral hydrate. The blood sample was collected from heartand serum amylase was assayed through using automatic biochemical analyzer.IL-1andIL-10were measured by enzyme linked immunosorbent assay(Elisa).Each pancreas washarvested and divided into two pieces:one piece was used for the MPO by Elisa and theother piece was for subsequent histopathological examination after H-E stain.Results:1.The serum level of amylase: The difference of serum level of amylase in each timepoint in NS and GT group was no significant (P>0.05). The serum level of amylasereached a peak at12h after the first injection and decreased significantly at24h in APgroup (P<0.05). The serum level of amylase was higher in each time point in AP groupcompared with those in other groups and the difference was significant (P<0.05).2.The level of MPO in pancrea: The difference of the level of MPO in pancrea in eachtime point in NS and GT group was no significant (P>0.05). The level of MPO in pancreareached a peak at12h after the first injection and decreased significantly at24h in AP andAP+GT group (P<0.05). The level of MPO in pancrea was higher in each time point inAP group compared with those in other groups and the difference was also significant(P<0.05).3. The serum level of inflammatory(IL-1) cytokine: The difference of serum level of IL-1in each time point in all the groups was no significant (P>0.05). The serum level of IL-1was higher in each time point in AP and AP+GT group compared with those in other twogroups and the difference was significant (P<0.05).While the difference was nosignificant in GT group compared to NS group.Moreover there was no difference in APand AP+GT group.4. The serum levels of anti-inflammatory(IL-10) cytokine: The difference of serum levelof IL-10in each time point in NS and GT group was no significant (P>0.05). The serumlevel of IL-10increased significantly with time and reached a peak at24h after the firstinjection in each time point in AP and AP+GT group (P<0.05). The serum level of IL-10 was higher in each time point in AP+GT group compared with those in other groups andthe difference was significant (P<0.05).5.The changes of pancrea in naked eyes and under the microscope: The pancrea in eachtime point in NS and GT group was no abnormal whatever in naked eyes and under themicroscope.In AP group,the pancrea in naked eyes showed bits of bleeding point, thepancrea turned pale and size enlarged with bits of ascite at3h.All the changes above weremore obvious at6h.Besides,the small intestine expanded with hyperemia and edema,andthe bleeding point increased in pancrea.The pancrea swelled and the intestine involvedliquids and there were pink ascite at12h.The pancrea swelled more even adhered to thesurrounding tissues, the intestine involved more liquids,the abdominal cavity involvedmore bloody ascites at24h. In AP group,the pancrea under the microscope showedinterstitial edema,minor inflammatory cells infiltration both in the pancreaticmesenchyme and around vessels at3h while the lobules were still clear to observe. Allthe changes above were more obvious at6h.The organizational structure of the pancreswas disturbed seriously at12h and24h.The pancrea were surrounded by massiveinflammatory cells.In AP+GT group,all the changes above were lesser compared with APgroup.6.The histopathological score of pancrea: The difference of the histopathological score ofpancrea in each time point in NS and GT group was no significant (P>0.05). Thehistopathological score of pancrea increased significantly with time and reached a peak at12h compared with3h,6h after the first injection in AP and AP+GT group (P<0.05). Thehistopathological score of pancrea was higher in each time point in AP compared withthose in other groups and the difference was significant (P<0.05).Conclusion:1.AP was induced successfully by intraperitoneal injection cerulein in mice.2.Galantide probably ameliorate the effects of AP by improving the levels ofinti-inflammatory(IL-10) cytokine,but it had no influences on inflammatory(IL-1)cytokine.