[Effects of hypoxia on the release of PDGF-B chain from pulmonary artery endothelial cells and on growth of pulmonary artery smooth muscle cells].

Platelet-derived growth factor (PDGF), content in hypoxic endothelial cells conditioned medium (HECCM) and normoxic endothelial cells conditioned medium (NECM) was determined using protein dot blot assay. The effects of HECCM and NECCM on the growth of pulmonary artery smooth muscle cells (PASMC) were assessed with [3H]-thymidine incorporation technique and flow cytometric analysis. PDGF content in HECCM was higher than that in NECCM. HECCM dramatically enhanced the DNA synthesis in PASMC and significantly promoted the cell cycle progression of PASMC from G0/G1 phase to S phase. In addition, administration of anti-PDGF-B chain monoclonal antibodies blocked markedly the DNA synthesis of PASMC stimulated by HECCM and obviously inhibited the entry of the cells from G0/G1 phase to S phase. These results suggest that increased PDGF release from pulmonary artery endothelial cells under hypoxia could stimulate the proliferation of PASMC which may induce pulmonary vascular reconstruction and involve in the development of hypoxic pulmonary hypertension.