Increased expression of ICAM-1 and VCAM-1 in the lung of nitrofen-induced congenital diaphragmatic hernia in rats

Abstract

Recently, increased expression of inflammatory cytokine, tumor necrosis factor (TNF)-alpha, has been reported in both humans and animal models with CDH and the decreased TNF-alpha expression in CDH lung after antenatal dexamethasone (Dex) treatment. Intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1 are induced by several inflammatory cytokines such as TNF-alpha. The aim of this study was to investigate pulmonary ICAM-1 and VCAM-1 expression in CDH lung in rats and to determine the effect of antenatal glucocorticoid. CDH model was induced in pregnant rats following administration of nitrofen on day 9.5 of gestation. In control animals, the same dose of olive oil was given without nitrofen. Dex (0.25 mg/kg) was given on day 18.5 and 19.5 of gestation. RT-PCR was performed to evaluate the relative amount of ICAM-1 and VCAM-1 mRNA expression. Fluorescein immunohistochemistry using anti-ICAM-1 and anti-VCAM-1 antibody was performed using light and confocal microscopy. ICAM-1 and VCAM-1 mRNA expression and ICAM-1 and VCAM-1 immunoreactivity were markedly increased in CDH lung compared to controls. Dex downregulated the expression of both adhesion molecules in the hypoplastic lung. Increased ICAM-1 and VCAM-1 mRNA expression in hypoplastic lungs would suggest that the increased local synthesis of pulmonary adhesion molecules may induce respiratory distress in CDH. Decreased expression of adhesion molecules in CDH lungs after Dex treatment suggests that antenatal glucocorticoids therapy may improve pulmonary immaturity and associated respiratory distress in nitrofen-induced CDH lung.