Telomere length of cultured chondrocytes from tissue cultured cartilage explants under the different oxidative conditions. After 144 hours' incubation of tissue culture, chondrocytes were isolated from cartilage explants, which were incubated in the presence or absence of H2O2 (0.1 μmol/l) or ascorbic acid-2-O-phosphate (Asc2P; 100.0 μmol/l). Telomere lengths in chondrocytes (1 × 106chondrocytes of passage 3–4 after isolation) were determined using the terminal restriction fragment (TRF) assay. (a) Representative image of telomere length assay of chondrocytes after 144 hours of incubation. Lane 1, pretreated group (telomere length of isolated chondrocytes from cartilage explants before tissue culture); lane 2, Asc2P + H2O2 treated group; lane 3, control group; lane 4, H2O2 treated group. (b) Treatment with Asc2P (lane 2) showed a tendency to elongate the mean telomere length of chondrocytes in comparison with control. Mean telomere length in H2O2 treated group was significantly shorter than in the control group (n = 9; P < 0.05).