Abstract: Objective To observe the time dependent changes of pancreas and lung injury in mice acute pancreatitis induced by caerulein，and compare the effects of mice acute pancreatitis model induced by different injection protocols of caerulein and lipopolysaccharides. Methods Mice acute pancreatitis were induced by different injection frequency of caerulein or caerulein combined with lipopolysaccharides, and plasma amylase activity was detected by starch-iodine colorimetry, and pancreas and lung injury severity was observed on paraffin section after HE staining. Results The injury of pancreas and lung in mice acute pancreatitis induced by caerulein was most severe at 4 h, which began to repair at 24 h, and basically returned to normal at 5 d. 4 h after last injection, the amylase activity in CAE7 group and CAE9 group was higher than that in the control group(6461±1078 U/dl vs 3093±331 U/dl; 6821±495 U/dl vs 3093±331 U/dl, all P<0.001), and that in CAE7+LPS group was higher than in CAE9 group(8912±465 U/dl vs 6821±495 U/dl, P<0.001), the histological score in CAE7 group and CAE9 group was higher than that in the control group(4.750±0.524 vs 0±0; 4.917±0.664 vs 0±0, all P<0.001), and that in CAE7+LPS group was higher than in CAE9 group(7.167±0.258 vs 4.917±0.664, P<0.001). Conclusion Mice acute pancreatitis can be successfully induced by 7 i.p. injections of caerulein (50 μg/kg body weight) at 1-hour intervals, caerulein combined with lipopolysaccharides other than increasing caerulein injection frequency can further exacerbate injury of pancreas.

Key words: mice, caerulein, lipopolysaccharides, acute pancreatitis, animal model