Effects of cyclic tensile strain on expression of glycosaminoglycans in rabbit chondrocytes of different ages

Objective To observe the effects of cyclic tensile strain (CTS) on in vitro expression of glycosaminoglycans (GAG) in rabbit chondrocytes of different ages.Methods Nine male New Zealand rabbits were grouped into juvenile (2 months), adult (8 months), and senior (31 months) groups. The bilateral knee joints were harvested using sterile technique from each rabbits. In each age group, rabbit articular chondrocytes were cultivated in vitro after randomization into a control group and a CTS group, with 6 specimens in each. In the next 3 days, CTS was applied (sin10％, 0. 5 Hz, 6 h/d) in the CTS group for 6 hours per day while no CTS was applied in the control group. After the first CTS treatment, the supernatant of cell culture was collected every 12 hours from each specimen in both groups to assess the GAG levels by Alcian blue assay.Results Expressions of GAG showed significant increases in both control and CTS groups in each age group ( P ＜ 0. 05) . Different age groups showed significant differences in the GAG secretion over different time points. Compared with the younger cells, the older ones showed the most significant difference in growth between the control and CTS groups at 12 hours, though the older cells produced less GAG than the younger ones in both groups at the end of the experiment (72 hours).Conclusions CTS can stimulate rabbit chondrocytes of different ages to secrete more GAG, and younger cells tend to produce more GAG than the older ones. Key words: Chondrocytes;  Strain;  Stress;  Glycosaminoglycans;  Rabbits