Biomedical Engineering Reference
In-Depth Information
PEMF stimulus
on bone
Gap junction
being the mediator
Promoted secretion
of OPG
Inhibited production
of RANKL
Increased OPG/RANKL ratio
in
RANK-RANKL-OPG
pathway
Decreased osteoclast activity
and increased osteoblastic
cell activity
Increased bone formation,
decreased bone resorption,
increased bone volume
FIGURE 8.1
Schematic diagram of the mathematical model structure of PEMF stimulated bone remodeling
at the cellular level.
then transformed as Equations (7.43), (7.44), and (7.46), and the initial values
of the model variables have already been listed in Table 7.2.
The model includes two different time scales: a short time scale is used
to describe the receptor-ligand reactions such as RANK-RANKL, OPG-
RANKL, and TGF-β with its receptor; and a long time scale is required to
capture the cell number changes such as OBP, OBA, and OCA. Note that the
receptor-ligand reaction is much faster than the changes in cell numbers;
therefore, a quasisteady-state assumption is used in the model to describe
the receptor-ligand reactions.
Using the short time scale and a quasisteady-state assumption, the expres-
sion of TGF-β is obtained and found to be the same in Equation (7.11).
Consequently, the activation and repression forms of TGF-β can be obtained
