【作者】 王宝利；

【导师】 邱明才；

【作者基本信息】 天津医科大学 ， 内分泌与代谢病学， 2002， 博士

【摘要】 护骨素(osteoprotegerin，OPG)及其同源配基核因子-κB受体激活物配基(receptor activator of nuclear factor κB ligand，RANKL)在破骨细胞分化和激活的调控中具有十分关键的作用。它们都由成骨细胞／骨髓基质细胞谱系表达。在允许浓度的M-CSF存在时，RANKL有力促进破骨细胞的分化、成熟和激活，并抑制细胞凋亡，是这些过程所必需的终极效应分子。OPG是RANKL的诱骗受体，通过与表达于成骨细胞／骨髓基质谱系表面的RANKL结合阻断RANKL对破骨细胞生成等的诱导作用。多数趋钙激素和细胞因子通过影响RANKL与OPG的相对表达水平来调控破骨细胞的分化和功能。 本实验通过研究RANKL和OPGmRNA在OVX小鼠骨组织中的相对表达水平，探讨RANKL和OPG在PMO发病中的意义。 我们将40只6周龄昆明小鼠随机分为5组，分别为Ⅰ组：对动物行假手术，术后1周处死；Ⅱ组：行卵巢切除手术，安慰剂治疗，术后1周处死；Ⅲ组：行卵巢切除手术，安慰剂治疗，术后5周处死；Ⅳ组：行卵巢切除手术，术后给苯甲酸雌二醇治疗，5周后处死；Ⅴ组：行假手术，术后5周处死。动物处死后，提取胫、股骨骨组织总RNA，以GAPDH作为内参照，RT-PCR扩增检测OVX小鼠RANKL和OPG mRNA表达水平，发现手术后第1、5周去卵巢小鼠骨组织RANKL mRNA表达水平都较假手术组明显增高，采用雌激素治疗可显著降低RANKL mRNA表达水平。而OPG mRNA表达水平在去卵巢后第1周时较假手术组显著降低，在第5周时却比假手术组显著升高，可能是机体的一种代偿机制。雌激素治疗组则介于去卵巢5周组和假手术组之间，但与二者均无显著性差异。以RANKL／OPG来表示RANKL和OPG mRNA的相对表达水平，我们发现，去卵巢后，RANKL／OPG显著增高，采用雌激素防 天津医科大学博士学位论文 治可使RANKL／OPG与假手术组无显著差异。 本研究结果提示PMO发病中雌激素减退所导致的骨丢失与骨组织RANKL 和OPG的mRNA相对表达水平紊乱有关。更多还原

【Abstract】 Receptor Activator of Nuclear Factor-Kappa B Ligand (RANKL), a membrane-bound protein expressed on osteoblasts and bone marrow stromal cells,is believed to induce osteoclast differentiation and activation by direct cell to cell interaction with osteoclast lineage cells.This induction is interrupted by osteoprotegerin (OPG),a soluble receptor of RANKL. Thus, OPG conteracts the stimulatory effect of RANKL on osteoclast differentiation and activation and it has been suggested that a high RANKL/OPG ratio is associated with an increased osteoclatogenesis while a low ratio with a decreased osteoclatogenesis. Previous in vitro studies indiated that other osteotropic hormones and factors such as PTH, 1, 25(OH)2D3, IL-1, IL-6 and TNF regulated osteoclastogenesis through the effect on RANKL/OPG ratio. The aim of the present study was to investigate the expression and regulation of RANKL and OPG in vivo in ovariectomized mice.forty female mice at six weeks of age were allocated into 5 groups, 8 in each. Group II > El and IVwere ovariectomized. Group IV were injected subcutaneusly with Benzoic estradiol for 5 weekstaneusly with Benzoic estradiol for 5 weeksone day after the ovariectomy. Group II and III were given placebo instead and sacrificed 1 and 5 weeks after the ovariectomy respectively. Group I and V were sham-operated and treated with placebo,then sacrificed l,and 5 weeks after ovariectomy. The tibia and femor were dissected out and mRNA levels of RANKL and OPG were studied using reverse transcription polyraerase chain reaction technique. The data showed that the mRNA level of RANKL was increased by ovariectomy while that of OPG was reduced in one week but increased in 5 weeks after ovariectomy, which seemed a compensation to the acceleration of bone loss. As a consequence, the ratio RANKL/OPG was increased by ovariectomy while reduced significantly when Benzoic estradiol was administrated.In summary, Our results indicate that Ovx-induced bone loss may be associated with the disturbance of RANKL/OPG.更多还原