Figure 2.

Structure and exogenous regulatory factors of the MRC. The MRC provides 95% of the energy required for cell survival, which is achieved by the activities of five mitochondrial respiratory enzyme complexes located in the IMM. These protein complexes carry out a series of tasks involving electron transfer and proton pumping. Mitochondrial respiratory complexes I-V contain specialized functional subunits that play a crucial role in regulating bone metabolism and differentiation. Additionally, certain chemical drugs and exogenous signaling proteins modulate mitochondrial complex activity, which can impact electron transport chain functionality and cellular processes. Disrupted MRC transmission can lead to mitochondrial homeostasis disruption, which may result in undesirable bone phenotypes. This dysfunction is the primary cause of bone aging and metabolic imbalance. Disorder within the bone microenvironment can lead to abnormal metabolism and functioning of bone-related cells, resulting in impaired energy metabolism, redox instability, cellular dysfunction, and cell death.