| Abstract: | The aim of this study was to characterize the age-related
changes of viscoelastic properties and deformation recovery of rabbit
chondrocytes in natural development of articular cartilage. The micropipette
aspiration combined with a standard linear viscoelastic solid model was used
to quantify all parameters of chondrocytes from different age groups.
Results indicate that the viscoelastic properties of chondrocytes in old
group exhibited a significantly lower instantaneous modulus (E_0),
equilibrium modulus (E_\infty ), and apparent viscosity (\mu )
compared with
those of young group (p<0.005) and adult group (p<0.005). But no differences
were found between young and adult group (p>0.1). The process of creep and
deformation recovery of chondrocytes has changed significantly during
natural development. The time t_E that old chondrocytes need to reach equilibrium is significantly
less than young and adult ones (p<0.05), but no differences were found
between young and adult ones (p>0.05). At the same time, maximal creep displacement
L_M in old group dramatically higher than young and adult group
(p<0.005), however, there were no differences between young and adult group
(p>0.05).
Comparisons of the deformation recovery ratio of
different age groups before 8 seconds have shown that the ratio value of
young group is significantly higher than those of adult and old ones
(p<0.005), and there were no significant difference between adult and old
ones (p>0.05). Additionally, there were no significant correlation between
the viscoelastic parameters and the ratio of the cell to micropipette diameter.
These results may be helpful for chondrocyte-based cartilage tissue
engineering. |
