OBJECTIVETo discuss the effect of taurine (Tau) on the proliferation of hypoxia-induced pulmonary artery smooth muscle cells (PASMCs), and study whether the extracellular signal-regulated kinase 1/2 (ERK1/2) signal pathway participated in the Tau-inhibited PASMC proliferation process and the possible molecular mechanism.

METHODThe primary culture was performed for PASMCs in rats. The second to fifth generations were adopted for the experiment. The Tau concentration was 80 mmol x L(-1). The concentration of ERK1/2 blocker (PD98059) was 50 micromol x L(-1). The drug administration time was 24 h. The effect of Tau on the PASMC proliferation was detected by MTT assay, immunofluorescence staining method and western blot under different conditions. The PASMCs were growing were divided into four groups: the normoxia group, the normoxia + Tau group, the hypoxia group and the hypoxia + Tau group. The Western blot was adopted to detect whether the ERK1/2 signal pathway participated in the Tau-inhibited PASMC proliferation process. Subsequently, the PASMCs were divided into five groups: the normoxia group, the hypoxia group, the hypoxia + Tau group, the hypoxia + Tau + PD98059 group and the hypoxia + PD98059 group.

RESULTHypoxia could induce the PASMC proliferation. Under the conditions of normoxia, Tau had no effect on the PASMC proliferation. Under the conditions of normoxia and hypoxia, Tau had no effect on the expression of the tumor necrosis factor-alpha (TNF-alpha) among PASMCs. Tau could reverse the expression up-regulation of hypoxia-induced proliferative cell nuclear antigen (PCNA) (P < 0.01) and Cyclin A (Cyclin A) (P < 0. 05). Under the conditions of normoxia, Tau had no effect on the expression of phosphoryl extracellular signal-regulated kinase 1/2 (p-ERK1/2). Hypoxia could up-regulate the p-ERK1/2 expression (P < 0.01). Tau could reverse the up-regulation of the hypoxia-induced p-ERK1/2 expression(P < 0.01). Both PD98059 and Tau could inhibit the up-regulated expressions of PCNA, Cyclin A and p-ERK1/2. According to the comparison between the single addition of Tau and PD98059 under conditions of hypoxia, the hypoxia + Tau + PD98059 group showed more significant down-regulation in the expressions of PCNA, Cyclin A and p-ERK1/2.

CONCLUSIONTau could inhibit the hypoxia-induced PASMC proliferation, and may regulate it through ERK1/2 pathway.