procedure described by farndale et al biochimica et biophyca acta 883 173 177 1986 immunohistochemical analysis on the paraffin embedded sections was performed to analyze expression of type ii collagen primary antibodies for type ii collagen biodesign international kennebunkport me were used at 1 50 dilution the reaction was carried out in a humid atmosphere at 37 u00b0 c for one hour the tissue sections were then washed 3 times in phosphate buffered saline pbs and incubated with a 1 200 dilution of rhodamine conjugated goat anti rabbit igg in pbs as a secondary antibody under the same conditions as described for the primary antibodies hoechst dye at 1 u03bcg ml was included in some experiments with the secondary antibody for nuclear staining the sections were washed three times in pbs and examined under a fluorescence microscope histological examination of the cultures showed that the chondrocytes passaged in cdrf p l accumulated an extracellular matrix which contained proteoglycans and collagen and formed a continuous layer of cartilaginous tissue these chondrocytes showed an increase in the amount of tissue produced and the matrical staining of proteoglycans when compared with chondrocyted propagated with dmem 10 fbs the cells propagated in cdrf p l readily underwent differentiation from a monolayer to round cells with lacunae chondrogenic morphology and expressed more type 11 collagen as compared to dmem 10 fbs the results of this experiment demonstrate that chondrocytes propagated in dm of the invention are capable.