The Expression of Thrombospondin-1 and Epidermal Growth Factor Receptor in Lungs of Hypoxic Rats

Objective: To test the role of thrombospondin-1 (TSP-1) and epidermal growth factor receptor (EGFR) in the development of hypoxic pulmonary hypertension. Methods: Twenty male Wistar rats were divided into two groups,control group and hypoxia group. Rats were exposed to air and isobaric hypoxia for 3 weeks to establish models for pulmonary hypertension. The pulmonary artery pressure was measured by right cardiac catheterization in two groups. The expressions of TSP-1 and EGFR protein in the lungs of rats were measured by immunohistochemical staining and in situ hybridization. The lung histological sections were examined using a computerized image analyzer. Results: The pulmonary artery pressure of rats increased in hypoxia group. The chronic hypoxia elicited the thickening of the wall and the narrowing of the lumen of pulmonary arterioles. 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%) were significantly higher in hypoxia group compared to those of control group (P 0.05). The positive staining of TSP-1, EGFR, TSP-1 mRNA and EGFR mRNA were significantly stronger in the wall of pulmonary arteriole of hypoxia group than those of control group (P 0.01). Conclusion: The TSP-1 and EGFR may play an important role in the pathogenesis process of hypoxic pulmonary vascular remodeling and pulmonary hypertension.