Biological Deciphering of the “Kidney Governing Bones” Theory in Traditional Chinese Medicine

Table 1

Mechanisms of bone homeostasis with the “KGB” theory.

Pathways of regulating bone homeostasis	Main mechanisms	References
As growth factors	Increasing bone mineral density, promoting bone formation, and maintaining bone structure by sex hormones/their receptors	[27–39, 69]
Regulate bone metabolism	Inhibiting osteoclast activity and increasing the number of osteoblasts by sex hormones	[41–51]
Regulate signaling pathways	Regulating the signaling pathway, such as BMP/Smads, Wnt/β-catenin, and OPG/RANKL/RANK by sex hormones	[53–57]
Affect endocrine function	Many components or hormones secreted by the kidney-EPO, 1,25-dihydroxy-vitamin D3, klotho, BMP-7, and exosomes were involved in the regulation of bone metabolism	[58–61]
Affect N-E-IN	Neuropeptide derived from the N-E-IN, such as serotonin, orexin, neuropeptide Y, substance P, galanin, and GABAergic, are involved in maintaining bone homeostasis	[64–68]