β_2肾上腺素能受体激动剂/拮抗剂对大鼠OB IGF-Ⅰ受体mRNA表达的影响

The effect of β_2 adrenergic agonist /antagonist on the mRNA expression of IGF-Ⅰ receptor in rat osteoblasts

目的通过研究β2肾上腺素能受体(ADRβ2R)激动剂/拮抗剂对大鼠成骨细胞(OB)成骨性指标胰岛素样生长因子-Ⅰ受体(IGF-ⅠR)mRNA表达的调控作用,探讨交感神经系统(SNS)对骨代谢影响的分子机制。方法取24 h内出生的新生SD大鼠的颅盖骨OB进行体外培养,通过细胞形态学观察、碱性磷酸酶重氮盐法染色和矿化结节茜素红S染色法来鉴定OB。将传至第三代的OB分成A组(ADRβ2R激动剂)、B组(ADRβ2R拮抗剂)和C组(对照组),分别用不同浓度的ADRβ2R激动剂(salbutamol)或ADRβ2R拮抗剂(ICI-118551)对OB处理24 h、72 h和96 h,检测IGF-ⅠR mRNA的表达变化,观察时间效应和剂量效应的关系。结果 ADRβ2R拮抗剂ICI-118551可以上调OB上IGF-ⅠR mRNA的表达;而ADRβ2R激动剂salbutamol则下调IGF-ⅠR mRNA的表达。两种调节作用均具有时间剂量依赖性。说明β2肾上腺素能受体(ADRβ2R)激动剂/拮抗剂可以通过作用于SD大鼠OB上的ADRβ2R而影响OB的骨形成指标IGF-ⅠR mRNA的表达,间接影响了骨形成因子IGF-Ⅰ的促进骨形成能力,从而调节骨代谢。

Objective By study of the effect ofβ2 adrenergic receptor （ ADRβ2 R） agonist/antagonist on the mRNA expression of insulin-like growth factor type Ⅰ receptor （ IGF-Ⅰ R ） in cultured rat osteoblasts （ OB ） in vitro, to explore the molecular mechanism of the effect of the sympathetic nervous system （ SNS） on bone metabolism.Methods Osteoblasts were isolated from the neonatal cranium of SD rats younger than 24 hours and passage cultured in vitro. The osteoblasts were identified using cytomorphology, ALP staining, and the Alizatin Bordeaux staining of mineralized nodules .The 3rd passage of osteoblasts were divided into 3 groups：A （ ADRβ2 R agonist group ） , B （ ADRβ2 R antagonist group ） , and C （ normal control group , NC） .Cells in group A and group B were treated with different concentrations of ADRβ2R agonist （salbutamol） or ADRβ2R antagonist （ICI-118551）.After culturing for 24 hours, 72 hours, and 96 hours, the mRNA expression of IGF-ⅠR was detected .The relationship between time-and dose-dependent efficiency was observed .Results ADRβ2 R antagonist ICI-118551 could up-regulate the mRNA expression of IGF-ⅠR, while ADRβ2 R agonist salbutamol down-regulated the mRNA expression of IGF-Ⅰ R.Both regulations showed time-and dose-dependent efficiency.Conclusion ADRβ2 R agonist/antagonist can regulate the mRNA expression of IGF-Ⅰ R through ADRβ2 R in rat OBs, thus indirectly influencing the ability of IGF-Ⅰin promoting bone formation and regulating bone metabolism .