Mechanisms of "kidney governing bones" theory in traditional Chinese medicine.

Studies conducted by our group on the mechanism of "kidney governing bones" theory in traditional Chinese medicine (TCM) are reviewed in this paper. Conclusions can be summarized as follows. (1) Neuroendocrine-immune network (NIN)-osteoclast regulatory pathway OPG-RANKL-RANK is one of the mechanisms of "kidney governing bones." Although kidney-reinforcing therapy is regarded as one of the holistic regulatory mechanisms of the body, characteristic holistic regulation in TCM can be reflected through nonselective regulation of the NIN during kidney reinforcement therapy, which can be used to treat osteoporosis through microadjustments in the microenvironment of the bone marrow. (2) Marrow exhaustion in TCM, which is the state wherein lipocytes in the bone marrow increase whereas other cells decrease, serves as the pathogenesis of osteoporosis brought about by failure of the "kidney governing bones." (3) The kidney in TCM can be regarded as a complex system comprising multiple functional units in the body, including the unit "governing bones." Kidney deficiency refers to a deficiency in only one or more units of the kidney system and not the whole system itself, which explains the kidney-reinforcing effect of many herbs; some herbs can treat osteoporosis, but some cannot. Although both classified as kidney-reinforcing agents, the former can resolve failure of the "kidney governing bones" unit while the latter regulates the failure of other units in the kidney system. Despite the current understanding on "kidney governing bones" theory, the mechanism of "kidney governing bones" remains complicated and unresolved. Thus, further studies in this area are warranted.