Roles of NHE-1 in the proliferation and apoptosis of pulmonary artery smooth muscle cells in rats.
OBJECTIVE
To evaluate the roles of Na+/H+ exchanger-1 (NHE-1) in the proliferation and apoptosis of pulmonary artery smooth muscle cells in rats.


METHODS
Twenty Wistar rats were randomized into control group and 3-week hypoxic group. Intracellular pH (pHi) of the smooth muscle was determined with fluorescence measurement of the pH-sensitive dye BCECF-AM, and the expression of NHE-1 mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). Primary culture of pulmonary artery smooth muscle cells in vitro was performed. In situ cell death detection kit (TUNEL) was used for studying the effect of specific NHE-1 inhibitor-dimethyl amiloride (DMA) on the apoptosis of muscle cells which had intracellular acidification.


RESULTS
pHi value and NHE-1 mRNA expression of pulmonary artery smooth muscle cells were significantly higher in the hypoxic group than in the control group (P < 0.01, P < 0.001). DMA elevated the apoptotic ratio remarkably. The effect was enhanced when DMA concentration increased and the time prolonged.


CONCLUSIONS
With the function of adjusting pHi, NHE-1 may play an important role in the proliferation and apoptosis of pulmonary artery smooth muscle cells.
Yao
Wei
W
Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. yaowei@cta.cq.cn
Qian
Guisheng
G
Yang
Xiaojing
X
D000818:Animals; D017209:Apoptosis; D002455:Cell Division; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D011651:Pulmonary Artery / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D017923:Sodium-Hydrogen Exchangers / Q000502:physiology*
D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1