Objective: To investigate the expression of neurokinin-1 receptor (NK-1R) in the lung tissue, and the relationship between expression of NK-1R and lung injury in rats with acute necrotizing pancreatitis (ANP).
Methods: One hundred and twenty adult Sprague-Dawley rats were randomly divided into ANP and control groups. Animals in group ANP were induced by the retrograde intraductal infusion of 5% sodium taurocholate (0.1 ml/kg), and animals in normal control group received laparotomy only. The accumulation of polymorphonuclear leukocytes in lung tissues was measured with myeloperoxidase (MPO) assay. Lung endothelial barrier destruction was measured by lung capillary permeability (LCP). Reverse transcription polymerase chain reaction (RT-PCR) was used to determine the mRNA expression of NK-1R, western blot analysis was used to determine NK-1R protein expression levels, and immunohistochemistry was used to localize expression site of NK-1R.
Results: NK-1R mRNA level was enhanced in the lung of ANP compared with normal control group. Western blot analysis showed overexpression of NK-1R protein level exited in ANP group. Statistical analysis revealed correlation between NK-1R mRNA and MPO (r=0.83, P<0.01) and LCP (r=0.79, P<0.01) respectively. With immunohistochemistry staining, moderate to strong NK-1R immunoreactivity was localized to alveolar membrane, I epithelium, II epithelium and polymorphonuclear leukocytes in the lung of ANP.
Conclusion: In ANP, overexpression of NK-1R contributes to disturbance of neuropeptides loop, resulting in aggregation of neutrophilic granulocyte and promoting deterioration of lung injury.