IL-6 promotes the expression of vascular endothelial growth factor through the p38 signalling pathway in hypertrophied adenoids in children

ObjectivesTo examine the expression of vascular endothelial growth factor (VEGF) in hypertrophied adenoids in children and investigate the possible regulatory mechanism.MethodsThirty-eight children with hypertrophied adenoids (moderate, 16; severe, 22) were enrolled to investigate the VEGF expression in the adenoid tissues using immunohistochemistry (IHC) and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The IL-6 concentration in the nasopharyngeal secretions was measured using an enzyme-linked immunosorbent assay (ELISA). VEGF mRNA expression was further measured in isolated adenoidal cells in vitro after IL-6 stimulation, and the activation of the p38 signalling pathway was determined by Western blot analysis.ResultsOur findings showed extensive immunoreactivity of VEGF in the hypertrophied adenoids in children. The levels of VEGF protein and mRNA were significantly higher in severely hypertrophied adenoids than in moderately hypertrophied adenoids (P < 0.05). The expression of IL-6 was detectable in the nasopharyngeal secretions, which was significantly associated with the severity of the hypertrophied adenoid. VEGF mRNA expression was upregulated in isolated adenoidal cells in vitro after IL-6 stimulation, and the p38 signalling pathway was activated.ConclusionsThe increased expression of VEGF in adenoid tissues suggests a possible role of the IL-6/VEGF axis in the pathogenesis of hypertrophied adenoids in children.