Cyclic electrochemical inactivation and restoration of competence of bone matrix to transform fibroblasts.

Brief exposure of rat bone matrix to highly charged electrochemicals had profound but reversible effects on its competence to transform fibroblasts into chondroblasts and osteoblasts. Suppression and subsequent reactivation of this function were influenced critically by the charge of the electrochemical reagent and the pH of the reaction mixture. In dilute acids, Evans Blue, a long electronegative molecule, suppressed transforming competence, whereas hexadimethrine, a polycationic quaternary ammonium base, failed to do so. A cycle of inactivation-restoration of transforming competence was achieved by sequential treatment of bone matrix with Evans Blue followed by hexadimethrine; an electrochemical complex was demonstrated by histochemistry. In dilute alkalies, hexadimethrine inhibited, whereas, Evans Blue did not suppress the transforming function of the bone matrix. Electric charge characteristics on the surface of the bone matrix are of crucial significance for the fibroblast-transforming attribute.