The Tolerance To Lipopolysacchride And The Therapeutic Effect Of Oxidized Phospholipids On Experimental Acute Pancreatitis

ObjectivesTo investigate the tolerance to lipopolysacchride(LPS) on experimental acute pancreatitis(AP) and explore the possible mechanism concerning gene expression profile changes of leucocytes; To investigate the therapeutic effect and mechanism of oxidized phospholipids, oxidized 1-palmitoyl-2-arachidonoyl-sn- glycero-3-phosphorylcholine (OXPAPC) on acute necrotizing pancreatitis(ANP) in rodent.Methods(1) Three hundred and ten C57BL/6J mice were randomly divided into normal control group(n=25), AP+NS group(n=25), NS+LPS group(n =130)and AP+LPS group (n=130) . The two latter groups were respectively subdivided into seven subgroups according to different dose of LPS. AP model was induced by seven times administration of cerulein (50 ug/kg). LPS was given 5 hours after the first celulein injection. LPS was replaced by NS in AP+ NS group. Cerulein was replaced by NS in NS+LPS group. Ten mice were randomly separated from every subgroup to investigate mortality rate for 7 days. Others were sacrificed at 12 hours after the first celulein or NS injection. Leucocytes were separated for gene chip test. Liver, lung, pancreas and blood serum were collected to investigate the pathological changes and serum levels of amylase (AMS) and lactate dehydrogenase (LDH). Gene expression profiles of leucocytes in control group, AP+NS group, NS +LPS (15mg/kg) group (n =25) and AP +LPS (15mg/kg) group (n =25) were studied with oligonucleotide microarrays of 12479 full length mouse genes respectively forthree times. (2) Eighty-eight C57BL/6J mice were randomly divided into two groups, ANP group(n =44) and ANP treated with OXPAPC group(n =44). ANP model was induced by seven times administration of cerulein (50 ug/kg) challenged by LPS(5 mg/kg)intraperitoneal injection. Treatment with OXPAPC (25mg/kg) was started 5 mins before LPS injection. Twenty mice of each group were separated to investigate survival rate. The others were sacrificed at the 9 h^ 12 hrs and 24 hrs after the first injection of cerulein, and the pancreas and blood serum were harvested. Eighty-eight SD rats were randomly divided into two groups, ANP group(n =44) and ANP treated with OXPAPC group(n =44). ANP model was induced by injecting sodium taurocholate(5%) into pancreatic duct. Treatment with OXPAPC (25mg/kg) was administrated at Ohr> 6 hrs after sodium taurocholate injection. Twenty rats of each group were separated to investigate survival rate. The others were sacrificed at 12 hrs, 24 hrs, 48 hrs and 72 hrs after injection of sodium taurocholate, and the pancreas and blood serum were collected. Serum levels of amylase(AMS) and lactate dehydrogenase (LDH) were measured by enzyme dynamics chemistry. Severity of pancreatitis was evaluated by histological scoring system. The activities of myeloperoxidase (MPO) in pancreas were determined by zymohistochemistry. Intrapancreatic TNF-alpha, IL-1P, ICAM-1 and E-selectin mRNA expressions in pancreas were studied by semi-quantitative RT-PCR. Inhibitor of kB kinase p (IKKp), protein38(p38) and c-Jun-N-terminal kinase 1(JNK1) protein were investigated by western blot. The binding activities of nuclear factor kB (NF-kB) and activated protein-1 (AP-1) to DNA were testifid by electrophoretic mobility shift assay (EMSA). Results(1) Mortality rate in both NS+LPS group and AP +LPS group was increased with the increasing of LPS dose. Mortality rate in AP +LPS group was significantly less than that in NS+LPS group with equal LPS dose(P<0.05). Serum level of LDH in AP +LPS group was significantly lower than that in NS+LPS group with equal LPS dose(P<0.05), but serum level of AMS was significantly higher than that in NS+LPS group with equal LPS dose(P<0.05).