Time-Dependent Phenotypic and Contractile Changes of Pulmonary Artery in Chronic Hypoxia-Induced Pulmonary Hypertension

• Main Authors: Daigo Aoshima (Author), Takahisa Murata (Author), Masatoshi Hori (Author), Hiroshi Ozaki (Author)
• Format: Book
• Published: Elsevier, 2009-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Abstract.: Phenotypic and contractile changes in pulmonary arterial smooth muscle cells (PASMCs) were examined in rats with pulmonary hypertension induced by hypoxia. Exposure to hypoxia induced pulmonary hypertension within 1 - 4 weeks. Staining with BrdU revealed that proliferative activities of PASMCs peaked at 1 week of hypoxic exposure, and then moderate proliferative activity was maintained for the next 2 - 4 weeks. The β-actin/α-actin ratio also increased at 1 - 2 weeks of exposure to hypoxia. Absolute contractility of the pulmonary arterial ring continuously decreased during hypoxia, whereas the basal active tonus of the pulmonary artery increased at 1 - 3 weeks. Nicardipine, the ETA-receptor antagonis, CI-1034 and the rhokinase inhibitor Y27632 partially inhibited the elevated active tonus. Endothelin-1 content in the pulmonary hypertensive lung was continuously increased during exposure to hypoxia. In conclusion, the hypoxia-induced proliferative activity of PASMCs comprised a transient phase followed by a sustained phase. The change in PASMCs from a contractile to a synthetic phenotype also correlated with proliferative activity, which subsequently decreased PASMC contractility. The continuous production of endothelin-1 upon hypoxic exposure might contribute to the increased basal tonus of the pulmonary arterial wall, which might subsequently increase pulmonic arterial pressure, resulting in accelerated pulmonary hypertension. Keywords:: pulmonary artery, hypoxia, contraction, endothelin-1, proliferation

Item Description

1347-8613
10.1254/jphs.09059FP