木通皂苷D通过丝裂原活化蛋白激酶信号通路促进大鼠骨髓间充质干细胞分化为成骨细胞

目的:探讨木通皂苷D(ASD)是否促进大鼠骨髓间充质干细胞(BMSCs)分化为成骨细胞及其机制。方法:分离培养大鼠BMSCs;观察ASD对其向成骨细胞分化的影响以及p38丝裂原激活蛋白激酶(p38MAPK)抑制剂SB203580和细胞外信号调节激酶(ERK)抑制剂PD098059的干预作用;检测BMSCs分化过程中碱性磷酸酶(ALP)活性和骨钙素(OC)含量;实时荧光定量PCR检测护骨素(OPG)和核因子κB受体活化因子配体(RANKL)mRNA的表达;Westernblotting法检测p38MAPK和ERK活性水平。结果:ASD处理后第9d,成骨性分化标志物OPGmRNA表达量明显增高,RANKLmRNA的表达量明显降低,同时显著提高BMSCs分化为成骨细胞的ALP活性和OC的表达,而且p38MAPK和ERK活性也显著增加。SB203580和PD098059则显著抑制ASD的成骨作用。结论:ASD在体外具有促进大鼠BMSCs向成骨细胞分化的作用,这一作用与MAPK途径的p38MAPK和ERK蛋白有关。

Akebia saponin D promotes differentiation of bone marrow mesenchymal stem cells into osteoblasts through MAPK signaling pathways

AIM:To explore the role of Akebia saponin D(ASD) in the differentiation of rat bone marrow-derived mesenchymal stem cells(BMSCs) into osteoblasts.METHODS: The rat BMSCs were cultured using routine methods.The effects of ASD on the differentiation of MSCs into osteoblasts were observed.The p38 mitogen-activated protein kinase(p38 MAPK) inhibitor SB203580 and extracellular signal-regulated kinase(ERK) inhibitor PD098059 were used to evaluate the mechanisms.The activity of alkaline phosphate(ALP) and content of osteocalcin(OC) were assayed during differentiation.The mRNA expression of osteoprotegerin(OPG) and receptor activator of nuclear factor-κB ligand(RANKL) was determined by real-time fluorescence quantitative PCR.The activity of p38 MAPK and ERK was measured by Western blotting.RESULTS: Six days after treatment with ASD,the mRNA expression of OPG significantly increased,while the mRNA level of RANKL significantly decreased in induced cells.ASD increased the activity of ALP and the content of OC.Moreover,ASD enhanced the activity of both p38 MAPK and ERK,which was inhibited by SB203580 and PD098059.SB203580 and PD098059 also inhibited the positive role of ASD in the differentiation of MSCs into osteoblasts.CONCLUSION: Akebia saponin D significantly enhances differentiation of rat BMSCs into osteoblasts in vitro,which may be mediated by the p38 MAPK and ERK signaling pathways.