Cartilage stem/progenitor cells were
counted and collected (passage 7) in logarithmic phase with
conventional method. 1–5 × 105 cells/pipe were transferred
into the flow tube and then centrifuged at 1200 r/min for
8min. After centrifugation the supernatant was discarded
and cells were washed in PBS twice. Add the precooling
70% ethanol to the tube and gently blow into single cell
suspension. Incubate them overnight at 4∘C. The next day,
they were centrifuged at 1200 r/min for 8 min to collect cells
and washed in PBS once. The cells were permeabilized with
0.25% Triton X-100 for 15min and washed in PBS twice. And
then cells were incubated in PBS containing the following
polyclonal antibodies, respectively: rabbit anti-collagen type
II (1 : 100), rabbit anti-collagen type I (1 : 100), rabbit antiaggrecan
1 (1 : 100), rabbit anti-SOX9 (1 : 100), rabbit antivimentin
(1 : 100), and rabbit anti-FGFR3 (1 : 100) over night at
4∘C. Next day, they were washed in PBS twice and incubated in PBS containing IgG. Finally, theywerewashed in PBS twice and subjected to single channel fluorescently activated cell
sorting (FACS) analysis.