[Age-related biomechanical properties of chondrocytes in rabbit knee articular cartilage].

OBJECTIVE

To fully demonstrate the alterations about the viscoelastic properties of chondrocytes in rabbit knee articular cartilage.

METHODS

Fifteen New Zealand white rabbits were divided into 3 age groups: young group (1 month), adult group (8 months) and old group (31 months). All rabbits were sacrificed and isolated from knee joint and digested into chondrocytes. The micropipette aspiration combined with Half-space model was used to quantify changes in viscoelastic properties of chondrocytes.

RESULTS

Experimental studies have shown that the changes of aspiration length with time in old group were obviously different from young group and adult group. But similar variations were found between the latter two groups. The viscoelastic properties of chondrocytes in old group exhibited a significantly lower instantaneous modulus E0 (0.55 +/- 0.05 kPa), equilibrium modulus E infinity (0.28 +/- 0.04 kPa) and apparent viscosity micro (4.10 +/- 0.61 kPa x s) as compared with young group (0.67 +/- 0.10), (0.37 +/- 0.09), (6.29 +/- 0.92) kPa x s (P < 0.001) versus adult group: (0.65 +/- 0.07), (0.35 +/- 0.05), (6.01 +/- 0.89) kPa x s (P < 0.001). But no difference were found between the latter two groups (P > 0.05).

CONCLUSION

In response to a step pressure, chondrocytes in each group exhibited the viscoelastic solid creep behavior. The viscoelastic properties of chondrocytes markedly decreased in old group.