Biomedical Engineering Reference
In-Depth Information
150
300 ng/mL IGF-I, 0.01 Hz at 10% strain
120
300 ng/mL IGF-I (only)
90
60
0 IGF-I, 0.01 Hz at 10% strain
30
0
0
4
8
12
16
20
Time (h)
FIGURE 11.19
Percent increase in time-dependent free aggrecan concentration in cartilage
disk response to individual and combination of IGF-I (300 ng/mL) and
dynamic loading (0.01 Hz at 10% strain) in comparison to basal condition
(i.e., 0 ng/mL IGF-I, no loading).
as a new dynamic balance of aggrecan production and degradation is estab-
lished.
Figure 11.19 presents predictions of the aggrecan accumulation in carti-
lage after chondrocytes are exposed to either IGF-I (300 ng/mL) or mechan-
ical stimuli (i.e., 0.01 Hz at 10% strain) or a combination of both. It shows
that in comparison to basal condition (i.e., 0 ng/mL IGF-I, no loading), the
component of free aggrecan synthesis stimulated by IGF-I increases with time
as IGF-I concentration increases. The component of biosynthesis induced by
mechanical loading is constant in time, that is, it is equivalent to an increased
basal rate. It can be seen that IGF-I induced biosynthesis has a larger con-
tribution than the mechanical loading regime investigated. When IGF-I and
mechanical stimulus are applied simultaneously, the degree of aggrecan stim-
ulation is greater than that achieved by either IGF-I or mechanical loading
alone.
11.6 Summary
This chapter started with a basic but fully coupled reactive-transport poroe-
lastic model within the theory of porous media. The model was extended to
Search WWH ::
Custom Search