<正> Objective : To investigate the effects of the transfection of NHE-1 ribozyme gene on the apoptosis of pulmonary artery smooth muscle cells （PASMC） in vitro. Methods: After NHE-1 ribozyme gene was designed

synthesized and then cloned into plasmid pLXSN

the recombined plasmid was tansfected into cultured rat PASMC. Expression of NHE-1 mRNA was detected with semi-quantitative RT-PCR. Intracellular pH （pHi） was measured by using fluorescence dye BCECF-AM. Cell cycle was measured with aid of flow cy-tometric DNA analysis. Cell apoptosis was observed with electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNED respectively. Results: The NHE-1 mRNA expression level and pHi value were significantly lower in PASMCs transfected with NHE-1 ribozyme gene than those transfected with pLXSN or without transfection. Meanwhile

the apoptosis rate of cells transfected with NHE-1 ribozyme gene was increased significantly. Morphology of cell apoptosis was observed in the cell