[Changes in smooth muscle cell proliferation in pulmonary arteries of rats given monocrotaline].

To study the relationship between proliferation of smooth muscle cells and structural changes in arteries of rats given monocrotaline, light microscopy with immunohistochemistry for bromodeoxyuridine (BrdU) was done after a single subcutaneous injection of monocrotaline. In increase in DNA synthesis in smooth muscle cells was seen from 3 days until 14 days after administration. Since this increase was seen before pulmonary hypertension and medial thickness developed some mechanisms that induce proliferation of pulmonary atrial smooth muscle may have been triggered soon after monocrotaline injection.