AIMTo investigate the impact of human urotensin II (hUII) on pulmonary arterial smooth muscle cell (PASMCs) cycle in vitro.

METHODSPASMCs dissected from Wistar rats were cultured in vitro, and incubated with series of concentrations of hUII (10(-7) mol/L, 10(-8) mol/L, 10(-9) mol/L) for 12 hours under normoxia or hypoxia condition, in order to analyze cell cycle progression and sub-G1 of PASMCs by using flow cytometric analysis stain of propidium iodide, which represented the proliferative and apoptotic changes in PASMCs.

RESULTSThe study showed a dose-dependent effect of hUII on PASMCs proliferation, which reflected the increase both in percentage of S phase of cell cycle and proliferative index (PI). The response of PASMCs to hUII was different under normoxic and hypoxic conditions. Compared with the control group, the treatment of 10(-7) mol/L, 10(-8) mol/L and 10(-9) mol/L hUII produced an increase of 175%, 136% and 118% under normoxia, respectively, and 135%, 118% and 103% under hypoxia, respectively. The concentration 10(-7) mol/L hUII played a significant role in PASMCs proliferation both under hypoxia and normoxia (P < 0.01). The results of cell cycle did not show sub-G1 of PASMCs at various concentrations of hUII.

CONCLUSIONhUII may stimulate DNA synthesis in S phase cell cycle of PASMCs and the proliferation of PASMCs under normoxia and hypoxia conditions, which promote cell growth in a dose-dependent manner.