Inflammatory mediators in acute pancreatitis

Application of caerulein and lipopolysaccharides in creating mouse models of mild or severe acute pancreatitis

AIM: To establish typical mouse models of mild or severe acute pancreatitis induced with caerulein (CAE) and/or lipopolysaccharides (LPS).

METHODS: Fifty healthy adult male C57 mice were randomly divided into five groups (with 10 mice in each group): a control group (CON group), the caerulein 7 group (CAE 7 group), a caerulein 7 plus LPS group (CAE 7 + LPS group), a caerulein 13 group (CAE 13 group), and a caerulein 13 plus LPS group (CAE 13 + LPS group). All the animals were killed three hours after the last intraperitoneal injection. The pancreas was carefully removed for microscopic examination and further observed under a transmission electron microscope (TEM). Serum amylase and lipase concentrations were assayed.

RESULTS: Enzyme levels and pathological score in all the experimental groups were significantly higher than those in the CON group (amylase lowest CAE 7 group: 27020 U/dL ± 3443 U/dL vs CON group: 2696 U/dL ± 400 U/dL, P < 0.01; lipase content lowest CAE 7 group: 1379 U/L ± 283 U/L vs CON group: 33 U/L ± 13 U/L, P < 0.01; pathological score lowest CAE 7 group: 5.8 ± 0.9 vs CON group: 0.1 ± 0.3, P < 0.01). Compared with the CAE 7 group, the enzyme levels and pathological score in the CAE 13 + LPS group increased more significantly (CAE 13 + LPS group amylase: 46969 U/dL ± 11852 U/dL vs CAE 7 group amylase: 27020 U/dL ± 3443 U/dL, P < 0.01; CAE13 + LPS group lipase: 1962 U/dL ± 496 U/dL vs CAE 7 group lipase: 1379 U/dL ± 283 U/dL, P < 0.05; CAE13 + LPS group pathological score : 11.1 ± 1.1 vs CAE 7 group pathological score : 5.8 ± 0.9, P < 0.05). The grade of pathological changes in the CAE 13 + LPS group was significantly higher than that in the CAE 13 group (CAE 13 + LPS group: 11.1 ± 1.1 vs CAE 13 group: 10.1 ± 0.99, P < 0.05). The ultrastructure of acinar cells was damaged in the CAE 7 group, and the rough endoplasmic reticulum and mitochondria were markedly swollen. However, in the CAE 13 + LPS group, the acinar cells were seriously damaged.

CONCLUSION: Caerulein alone by intraperitoneal injection 7 times can be used to prepare a typical model of acute edematous pancreatitis, and caerulein by intraperitoneal injection 13 times plus LPS at the last time can be used to produce typical acute necrotizing pancreatitis.