In the present study, the effect of emodin on pulmonary inflammation and MPO activity was evaluated. The TNF and IL 6 levels and MPO activity were decreased after treatment with emodin . Emodin promoted expression of claudin 4, claudin 5 and occludin in rats with acute pancreatitis The expression levels of claudin 4, claudin 5, and occludin were markedly lower in experimental group than in control group . Immunolocalization of claudin 4, claudin 5 and occludin in lung tissue samples was investigated with immunohistochemical staining. Moderate immunostaining of claudin 4, claudin 5, and occludin was detected in control group, which was distributed in alveolar epithelium, vascular endothelium, and bronchial epithelium, respectively . Immunostaining of claudin 4, claudin 5, and occludin was markedly decreased in experimental group , and moderately elevated after treatment with emodin . RT PCR analysis showed that emodin could increase the expression levels of claudin 4, claudin 5, and occludin mRNA in rats with acute pancreatitis .
Western blotting analysis showed that the expression levels of claudin 4, claudin 5, and occludin were significantly higher in emodin treatment group than in pancreatitis group . Emodin enhanced alveolar epithelial barrier function in rats with acute pancreatitis The pulmonary dye extravasation, as a marker of local paracellular permeability, was significantly reduced in rats with acute pancreatitis after treatment with emodin, indicating Roscovitine ic50 selleck that emodin can augment alveolar epithelial barrier function . DISCUSSION In the present study, we identified the down regulation of claudin 4, claudin 5, and occludin in rats with acute pancreatitis induced by sodium taurocholate. Intravenous administration of emodin promoted the downregulation of tight junctions, enhanced alveolar epithelial barrier function, attenuated pulmonary edema and inflammatory infiltration in rats with acute pancreatitis. Among the systemic complications of severe acute pancreatitis, pulmonary complication, also known as pancreatitis associated lung injury, is the most frequent and serious .
Pancreatitis associated lung injury is characterized by significant pulmonary edema, hyperemia and inflammatory infiltration in alveoli . Increased interstitial edema cuts down the transport of carbon dioxide through the alveolar barrier, Nafamostat kinase inhibitor causing respiratory distress syndrome. It has been recently reported that claudins, the key components of tight junctions, restrict paracellular movement of water, proteins, and solutes across cellular barriers including pulmonary vascular endothelium and alveolar epithelium . Disruption of claudins impairs barrier function and increases paracellular permeability, which may allow noxious contents to enter pulmonary interstitium and alveoli, further aggravating pulmonary edema and inflammation .