从铁调素对铁过载的调控作用探讨“肾主骨”机理

"Kidney governs bone" theory is one of the most important theories. Recent studies have demonstrated that,iron overload is one of the important reasons of osteoporosis, while the hepcidin is the key material to correct the "iron overload".The effect of hepcidin on regulation of iron homeostasis is realized through the receptor Fpn ,and osteoblast membrane has hepcidin receptor Fpn1.So this project intends to adopt the research methods of in vivo and in vitro experiments combining.In vivo experiments, ovariectomized rats is the animal model of deficiency of the kidney; in vitro experiments, hepatic cells which contain hepcidin will be co-cultured with osteoblasts ,because the liver is the specific secretion organ of hepcidin and use Zuogui pill and its serum as a means of intervention.From the perspective of that hepcidin regulated iron overload , in-depth study mechanism of"Kidney governs bone". Studies of this theory based on hepcidin regulating iron overload have not been seen.The study in-depth explore mechanism of"Kidney governs bone" from this perspective will not only help researchers to understand the scientific essence of "Kidney governs bone" theory profoundly, but provide experimental basis for the treatment of osteoporosis with TCM. In summary, this study had important theoretical and practical value.

"肾主骨"是中医的重要理论之一。近年研究证明，组织中游离铁过多导致的铁过载是骨质疏松症发生的重要原因之一，而铁调素是体内维持铁稳态,纠正"铁过载"的关键物质，它对铁稳态的调控作用主要通过细胞表面的受体膜转铁蛋白（Fpn）来实现，而成骨细胞膜上存在铁调素受体Fpn1。据此，本项目拟采用体内实验与体外实验相结合的方法进行研究。体内实验以卵巢切除大鼠作为肾虚动物模型；由于肝细胞是分泌铁调素的特异性器官，所以体外实验将含有铁调素的肝细胞与成骨细胞进行共同培养；分别采用左归丸及其含药血清进行干预，从铁调素对铁过载调控的角度深入探讨"肾主骨"机理。目前尚未见到有关报道。本研究从这一角度对"肾主骨"机理进行深入探讨，不仅可能进一步揭示"肾主骨"理论的科学内涵，而且也可为中医治疗骨质疏松症提供进一步的实验依据；因此，具有重要的理论意义和较高的实用价值。

本研究从铁调素所维持的铁稳态角度，深入探讨“肾主骨”的机理。研究分为体内实验和体外实验两部分进行。体内实验以卵巢切除（OVX）大鼠做为肾虚型骨质疏松症动物模型，选用补肾法经典方剂左归丸进行干预，采用骨形态学观察、骨密度检测、ELISA等方法，观察大鼠在“肾虚”状态下以及应用左归丸“补肾”后，铁调素水平以及由其所导致的铁稳态和大鼠骨量、骨形成与骨吸收的变化情况。体外实验将含有铁调素的肝细胞与成骨细胞共同培养，用左归丸含药血清进行干预，观察肝细胞分泌铁调素的水平变化，成骨细胞的增殖、凋亡情况，细胞内铁离子含量、Fpn1表达水平等的变化情况。研究结果显示：在卵巢切除即肾虚状态下，机体铁调素水平下降导致铁过载，进而使破骨细胞异常活跃，骨量丢失；而左归丸可通过提高铁调素水平，改善卵巢切除所致的铁过载，进而对下游的OPG/RANKL信号通路起到调节作用，最终使成骨细胞凋亡减少且破骨细胞活性降低，从而减少了骨量丢失。说明铁调素对铁过载的调节作用在“肾主骨”中起着重要作用。这一研究结果从铁调素所维持的铁稳态角度，进一步阐明了“肾主骨”机理，也为中医治疗骨质疏松症提供进一步的科学依据。因此，具有重要的理论意义和较高的实用价值。