The effect of cadmium on the collagen solubility of embryonic chick bone in tissue culture

The effect of cadmium (Cd) on the solubility of bone collagen was examined in cultured tibiae from 9-day chick embryos. The solubility of collagen was not significantly increased by 8.9 microM Cd, but showed a significant increase at 13.4 microM Cd. As the [3H]hydroxyproline (Hyp) formation was inhibited by Cd at 8.9 and 13.4 microM [3H]Hyp formation and collagen solubility were investigated in the presence of 200 microM Fe2+, a metal which is known to prevent the inhibitory effects of Cd on prolyl hydroxylase in vitro. Fe affected neither a decrease in [3H]Hyp formation nor an increase in collagen solubility caused by Cd. This suggests that a Cd-induced increase in collagen solubility may be due to the decrease of lysyl oxidase activity, not to the formation of underhydroxylated collagen. Zn at 48 and 134 microM depressed the Cd-induced increase in collagen solubility, but caused no increase in collagen solubility. Our present and previous results suggest that Zn can protect the disturbance of both the collagen synthesis and the collagen cross linking caused by Cd.