低氧诱导因子-1α在绝经后骨质疏松中调控作用的实验研究

目的探讨在绝经后骨质疏松的发生、发展过程中,低氧诱导因子-1α（HIF-1α）对于成骨细胞功能的调控作用。方法2004年10月至2006年5月,应用Cre—Loxp重组酶技术,建立成骨细胞条件性敲除HIF-1α小鼠,取3个月龄雌性野生型和敲除型小鼠各24只行卵巢切除术,术后0、4、8周取材行HE染色、四环素荧光双标记、Micro-CT、RT—PCR、Western-blotting检测。结果与野生型小鼠相比,敲除型小鼠骨小梁的数目、体积、厚度,骨密度,骨矿沉积速度,血管内皮生长因子（VEGF）、RunX2、ALP、OC基因在mRNA水平的表达,VEGF、RunX2在蛋白水平的表达均明显降低,尤其以术后8周最为明显。结论在绝经后骨质疏松的发生、发展过程中,成骨细胞条件性敲除HIF-1α后成骨功能降低,HIF-1α能够调控成骨细胞的成骨功能。

The regulation of hypoxia inducible factor-1alpha on osteoblast function in postmenopausal osteoporosis

OBJECTIVE: To study the regulation of hypoxia inducible factor-1alpha (HIF-1alpha) on osteoblast function in postmenopausal osteoporosis. METHODS: From October 2004 to May 2006, Cre-Loxp recombinase was used to create mice which the HIF-1alpha gene in osteoblasts was conditional knock-out, 24 female wild-type (WT) mice and 24 female conditional knock-out (CKO) mice of 3 months old were operated on ovariotomy. At 0,4,8 weeks after operation, bone histomorphometry parameters were measured with computer image analysis in HE stain sections and in tetracycline bone double labeling fluorescence sections; Bone density and the trabecular bone architecture parameters were measured by Micro-CT; The mRNA expression of vascular endothelial growth factors (VEGF), RunX2, OC, ALP were detected with quantitative RT-PCR; The protein expression of VEGF and RunX2 were detected with Western-blotting. RESULTS: In CKO mice, the trabecular number, volume, thickness, bone density, mineral apposition rate (MAR), the expression of VEGF, RunX2, OC, ALP on mRNA level and the expression of VEGF, RunX2 on protein level decreased significantly compared with WT mice especially in 8 weeks after operation. CONCLUSIONS: The bone formation ability of osteoblasts in CKO mice was reduced compared with WT mice after ovariotomy. HIF-1alpha can regulate the bone formation ability of osteoblasts in postmenopausal osteoporosis.