ABSTRACT
Objective To establish a mouse model of biliogenic severe acute pancreatitis (SAP) by using a self-made device for retrograde injection of sodium taurocholate into common bile duct,and to investigate the improvement of the device on retrograde injection of sodium taurocholate into common bile duct and its safety.Methods Thirty-six adult male ICR mice were randomly divided into biliogenic SAP model group and sham group,with 18 mice in each group.A 40 U disposable insulin syringe,a 200 μL tips and a 25 μL micro-syringer were used as basic materials for making the mouse common bile duct injection device [National Utility Model Patent (ZL 2014 2 0694365.4)].In model group,3.5％ sodium taurocholate (1 mL/kg) was injected retrogradely into the common bile duct of mice,whilst in sham group,the mice underwent the injection of equal amount of normal saline instead.Six mice in each group were sacrificed at 6,24 and 48 hours after operation,and the abdominal aortic blood was collected.Serum amylase (AMY),alanine aminotransferase (ALT),creatine kinase-MB (CK-MB),serum creatinine (SCr),oxygenation index (PaO2/FiO2) as well as serum Ca2+ were.determined.Pathological change in pancreas was observed under conventional light microscopy after hematoxylin and eosiu (HE) staining,and the impairment was evaluated by a widely used score system.Results The injection device was easily placed into mouse common bile duct under macroscopic observation.Six hours after operation,the levels of serum AMY,ALT and SCr in model group were significantly higher than those in sham group,and peaked at 24 hours,and they slightly decreased at 48 hours,which were still significantly higher than those of the sham group [24-hour AMY (U/L):7 325 ± 1 154 vs.1 737 ± 197,24-hour ALT (U/L):176.0±5.0 vs.38.3 ± 2.0,24-hour SCr (tmol/L):46.3 ± 1.5 vs.17.8 ±0.6,all P ＜ 0.01].The level of CK-MB at 6 hours in the model group was significantly higher than that of the sham group,and peaked at 48 hours (U/L:749.8±42.2 vs.383.3±35.5 at 6 hours,3 340.1 ± 203.6 vs.704.6 ± 63.5 at 48 hours,both P ＜ 0.01).PaO2/FiO2 at 6 hours after the operation in model group was significantly lower than that of sham group,then it began to rise at the similar level in sham group at 48 hours [mmHg (1 mmHg =0.133 kPa):327.5±33.8 vs.424.8±31.0 at 6 hours,P ＜ 0.01;429.8 ±41.8 vs.464.7±43.3 at 48 hours,P ＞ 0.05].Ca2+ level in model group was continuously decreased after operation,and it was significantly lower than that of sham group at 48 hours (mmol/L:1.58 ± 0.14 vs.2.45 ± 0.21,P ＜ 0.01).The pancreatic edema was obvious after operation in sham group,with the observation time prolongation,the changes were gradually improved;pancreatic focal necrosis was found at 6 hours after operation in model group,and it was secondary aggravated,and pancreatic lobule structure disappearance and inflammatory cells extensive infiltration was found at 48 hours.Pathological score of the model group was significantly higher than that of sham group at each time point,and peaked at 48 hours (13.3 ±0.3 vs.3.0±0.1,P ＜ 0.01).Conclusion It is a highly efficient and low-cost way to induce biliogenic SAP in mice by retrograde injection of 3.5％ sodium deoxycholate into common bile duct via the self-made injection device,and the model conformed to the clinical characteristics of biliogenic SAP.