Autoradiographic study of chick limb cartilage in vivo and in vitro and its response to mitomycin C (MMC).

Effect of mitomycin C on mucopolysaccharide synthesis by the cartilage cells of chick limb bud (5-9 days old) was investigated both in vivo and in vitro by the uptake study of 35S. Control specimens (both in vivo and in vitro) showed higher concentration of silver grains, mostly intercellular, in the initial stages. Hypertrophy of cartilage cells at later stages reduced the matrix, leading to a corresponding decrease in the accumulation of silver grains. In the treated groups, both in vivo and in vitro, the silver grains were found to be less in number during the initial stage of growth than in the corresponding controls, due to the suppressive effect of the mitomycin C. However, during the later period of growth, uptake of 35S was more in the matrix of treated specimens, which was apparently not reduced due to lack of hypertrophy of cartilage cells. The mechanism of the suppressive effect of mitomycin C seems similar in vivo and in vitro.