Differences in platelet endothelial cell adhesion molecule-1 expression between peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis

Abstract

Aim: To investigate the changes of platelet endothelial cell adhesion molecule-1 (PECAM-1) expression on polymorphonuclear leukocytes (PMNs) in peripheral circulation and pancreatic microcirculation in cerulein-induced acute edematous pancreatitis (AEP).

Methods: Fifty Wistar rats were randomly divided into control group (n = 10) and AEP group (n = 40). A model of AEP was established by subcutaneous injection of cerulein 5.5 and 7.5 mug/kg at 0 and 1 h after the beginning of experiment respectively. PECAM-1 expression on PMNs from splenic vein and inferior vena cava was determined by RT-PCR at mRNA level and determined by flow cytometry at protein level.

Results: In experimental rats, an increased PECAM-1 mRNA expression was seen from 4 to 8 h of AEP in peripheral circulation (0.77+/-0.25%, 0.76+/-0.28%, 0.89+/-0.30%, 1.00+/-0.21%), while in pancreatic microcirculation, expression decreased from 2 h and reached the lowest level at 6 h of AEP (0.78+/-0.29%, 0.75+/-0.26%, 0.62+/-0.28%, 0.66+/-0.20%). There were significant differences at 8-h time point of AEP between peripheral circulation and pancreatic microcirculation (1.00+/-0.21% vs 0.66+/-0.20%, P<0.05). Meanwhile, the difference at protein level was also found.

Conclusion: A reverse expression of PECAM-1 on PMNs was found between peripheral circulation and pancreatic microcirculation, suggesting that inhibition of PECAM-1 expression may improve the pathological change of AEP.

Figure 1

RT-PCR analysis of PMNs PECAM-1. A: Expression of on PMNs PECAM-1 mRNA in peripheral circulation. Lanes 1, 2, 3 and 4: PECAM-1 cDNA after amplification from RNA of PMNs from inferior vena cava at 2, 4, 6 and 8-h time points of AEP respectively; B: Expression of on PMNs PECAM-1 mRNA on in pancreatic microcirculation. Lanes 1, 2, 3 and 4: PECAM-1 cDNA after amplification from RNA of PMNs from splenic vein at 2, 4, 6 and 8-h time points of AEP respectively; C: Values of the density of PECAM-1 RT-PCR product normalized to that of β-actin in the same RNA sample. Symbols are: (ν) peripheral circulation; (ο) pancreatic microcirculation. ^aP<0.05, by one-way ANOVA.

Figure 2

Flow cytometry analysis of PECAM-1 on PMNs. ^aP<0.05 vs peripheral circulation values.