Expression of epidermal growth factor receptor in the lung of rats exposed to hypoxia

【Objective】 To test the role of epidermal growth factor receptor(EGFR) in the development of hypoxic pulmonary hypertension.【Methods】 Twenty male Wistar rats were divided into two groups and exposed to air and isobaric hypoxia for 3 weeks,respectively.The pulmonary artery pressure was measured by right cardiac catheterization.The expression of EGFR protein and EGFR mRNA in the lungs of rats were measured by immunohistochemical staining and in situ hybridization.The histological sections of the lungs were examined using a computerized image analyzer.【Results】 The pulmonary artery pressure in the exposed rats increased.The chronic hypoxia also elicited the thicking of the wall and the narrowing of the lumen of pulmonary arterioles.It led to the increases of the pulmonary artery pressure,the index of right ventricular hypertrophy(RV/(LV+S),the ratio of vascular wall thickness/vascular external diameter(WA%) and the ratio of vascular wall area/total vascular area(WT%) compared to the controls PAP(2.86±0.39) kPa vs(1.35±0.28 kPa);(RV/(LV+S):(43.53±3.38) vs(23.68±3.48);WT%:(35.24±11.2) vs(23.63±9.74);WA%:(55.09±12.38) vs(41.62±12.83) respectively,P 0.05).The positive staining of EGFR protein and EGFRmRNA in the wall of pulmonary arteriole of the exposed rats were significantly stronger than those of controls(P 0.01).【Conclusions】 The EGFR may play an important role in the pathogenesis process of hypoxic pulmonary vascular remodeling and pulmonary hypertension.