人成骨细胞增殖和分化与生长激素释放肽

Effects of ghrelin on the proliferation and differentiation of human osteoblasts

背景:有研究表明生长激素释放肽对体外培养大鼠成骨细胞增殖有促进作用,但对人成骨细胞增殖和分化是否有影响却少有报道。目的:探讨生长激素释放肽对人成骨细胞增殖和分化的影响。方法:取正常成人髂前上棘松质骨,分离出成骨细胞并进行体外培养,应用RT-PCR法检测生长激素促分泌素受体的表达;3H-掺入法检测成骨细胞增殖;Westernblot检测与成骨细胞分化相关的Runx2蛋白表达;α-磷酸奈酚法和放射免疫法观察生长激素释放肽对人成骨细胞分化的影响。结果与结论:人成骨细胞可表达生长激素促分泌素受体mRNA和生长激素促分泌素受体蛋白。生长激素释放肽促进人成骨细胞增殖(P<0.05或P<0.01),且呈剂量依赖性,而且可增加碱性磷酸酶的活性并促进骨钙素的分泌(P<0.05或P<0.01),但对人成骨细胞中Runx2蛋白的表达无影响。结果提示,生长激素释放肽能促进人成骨细胞增殖和分化。

BACKGROUND： Ghrelin has been reported to have a role in the regulation of bone metabolism on rats, but whether it has the effects on the proliferation and differentiation of human osteoblasts remains unclear. OBJECTIVE： To investigate the effects of ghrelin on the proliferation and differentiation of human osteoblasts. METHODS： Human osteoblasts were separated from normal human cancellous bone in anterior superior spine, and cultured in vitro. The expression of GHS-R1a in human osteoblasts was verified by semiquantitative reverse transcription-polymerase chain reaction （RT-PCR）. Human osteoblasts proliferation was assessed by measuring [3H] thymidine （2Ci/ml） incorporation into trichloroacetic acid （TCA）-insoluble material. The differentiations of human osteoblasts were evaluated by RIA and ELISA. The expression of Runx2 in human osteoblasts was detected by Western blot. RESULTS AND CONCLUTION： The mRNA and protein of GHS-R1a were expressed in human osteoblasts. Ghrelin promoted the proliferation of human osteoblasts in a dose-dependent manner （P0.01）. Ghrelin increased the activity of alkaline phosphatase （P0.01） and the secretion of osteocalcin （P0.01） in human osteoblasts. But the protein expression levels of Runx2 in human osteoblasts were no significantly changed by the intervention of ghrelin. The findings demonstrated that ghrelin can efficiently promote the proliferation and differentiation of human osteoblasts.