人参皂甙Rb1通过Rho/Rho激酶通路影响低氧诱导大鼠肺动脉平滑肌细胞增殖及SERT和5-HT_(1B)R表达

目的:观察人参皂甙Rb1对低氧性大鼠肺动脉平滑肌细胞(PASMCs)5-羟色胺转运体(SERT)和5-羟色胺1B受体(5-HT_(1B)R)表达及细胞增殖的影响,并探讨Rho/Rho激酶通路在其中的作用。方法:分离并培养健康雄性SD大鼠PASMCs,随机分为常氧组(normal组)、低氧组(hypoxia组)以及低氧加50、100和200 mg/L人参皂甙Rb1组(HR50、HR100和HR200组),采用CCK-8、Brd U结合流式细胞术、Western blot及RT-PCR等方法,观察大鼠PASMCs的增殖程度以及SERT和5-HT_(1B)R的mRNA和蛋白表达变化;另取PASMCs分为normal组、hypoxia组、HR200组和低氧加Y-27632组(HY组),检测Rho激酶(ROCK1)mRNA表达和肌球蛋白磷酸酶目标亚单位1(MYPT1)磷酸化水平。结果:与normal组比较,hypoxia组PASMCs增殖明显(P0.01);与hypoxia组比较,人参皂甙Rb1可明显抑制PASMCs的增殖(P0.01),并浓度依赖性抑制SERT和5-HT_(1B)R的mRNA与蛋白表达(P0.05);HR200组可明显抑制ROCK1的mRNA表达和MYPT1磷酸化水平(P0.01),与HY组相比较,差异无统计学显著性。结论:低氧能诱导大鼠PASMCs增殖,上调SERT和5-HT_(1B)R表达;人参皂甙Rb1能浓度依赖性抑制这种作用,其机制可能与抑制Rho/Rho激酶通路表达有关。

Effect of ginsenoside Rb1 on proliferation and serotonin transporter and 5-HT1B R expression in hypoxia-induced rat pulmonary artery smooth muscle cells via Rho/Rho-kinase pathway

AIM: To observe the effect of ginsenoside Rb1 on the proliferation and the expression of serotonin transporter (SERT), 5-hydroxytryptamine 1B receptor (5HT_1BR) in rat pulmonary artery smooth muscle cells (PASMCs) under hypoxia condition and the relationship with Rho/Rho-kinase signal pathway.METHODS: PASMCs were isolated from the adult male SD rats and primarily cultured. The subcultured cells from the 4th generation to the 6th generation were harvested and divided into normal group, and hypoxia group, different concentrations of Rb1 incubation groups treated with 50, 100 and 200 mg/L ginsenoside Rb1 under hypoxia (HR50, HR100 and HR200 groups, respectively). The viability of the PASMCs was measured by CCK-8 assay. BrdU positive cells were determined using flow cytometry. The expression of serotonin transporter and 5HT_1BR at mRNA and protein levels was detected by RT-PCR and Western blot, respectively. The PASMCs were randomly divided into normal group, hypoxia group, HR200 group and hypoxia+Y-27632 incubation group (HY group). The mRNA expression of Rho-kinase and phosphorylated myosin phosphatase target subunit 1 (p-MYPT1) protein level were investigated by RT-PCR and Western blot, respectively.RESULTS: Compared with normal group, the proliferation of PASMCs in hypoxia group was significantly increased (P<0.01). The cell viability and the expression of SERT and 5HT_1BR at mRNA and protein levels in all different concentrations of Rb1 groups were obviously decreased compared with hypoxia group (P<0.05). The mRNA expression of Rho-kinase and protein level of p-MYPT1 were markedly decreased in HR200 group, and no significant difference compared with HY group was observed (P<0.01).CONCLUSION: Treatment with ginsenoside Rb1 might prevent hypoxia-induced proliferation of PASMCs and over-expression of SERT and 5HT_1BR through inhibiting the Rho/Rho-kinase pathway.