[Effects of hypoxia on proliferation of pulmonary arterial smooth muscle cells].

To investigate the effects of hypoxia on the proliferation of different diameter intra-pulmonary artery smooth muscle cells (PASMCs), and to study the possible signal transduction pathway in proliferation caused by hypoxia. PASMCs were isolated from three different size of pulmonary arteries (>1 000 microm, 500-800 microm, 300-400 microm diameter) and cultured separately. 3H-TdR incorporation and cell number were used to measure cell proliferation. 3H-TdR incorporation and cell number of PASMCs from three sizes of pulmonary artery (> 1 000 microm, 500-800 microm, 800-400 microm diameter) increased 23.5% and 11.1%, 60.0% and 33.8%, 141.4% and 52.0%, respectively. Calcium antagonist (verapamil), PKC inhibitor (staurosporine), and Na(+)-H+ exchange inhibitor (amiloride) were used in PASMCs isolated from 300-400 microm diameter pulmonary artery. The results showed that verapamil, staurosporine and amiloride could notably block hypoxia-induced increase 3H-TdR incorporation and cell number. Proliferation of pulmonary artery smooth muscle cell responded to hypoxia differently according to the artery size; activation of calcium channel, PKC and Na(+)-H+ exchange might mediate the proliferation initiated by hypoxia.