ALKALINE-PHOSPHATASE AND TYPE-I COLLAGEN GENE EXPRESSIONS WERE REDUCED BY HYDROXYL RADICAL-TREATED FIBRONECTIN SUBSTRATUM

The influence of fibronectin (FN) substratum treated with hydroxyl rad icals ((OH)-O-.) generated by the H2O2-Cu2+ systems on osteoblast cell s was studied. Sodium dodecyl sulfate-polyacrylamide gel electrophores is analysis revealed that FN was degradated and/or modified by (OH)-O- . treatment, The calcified bone nodule formation of osteoblast cells c ultured on (OH)-O-. treated FN-coated wells was significantly lower co mpared to those on intact FN-coated wells, Alkaline phosphatase (ALP) activity and the secretion of type I collagen were reduced by (OH)-O-. -treated FN. By RT-PCR mRNA levels of ALP and type I collagen genes we re also diminished. These findings suggested that the (OH)-O-. damaged FN molecules and reduced the bone formation of osteoblast cells via i nhibition of proliferation and/or differentiation of osteoblast progen itors and the calcification process. (C) 1998 Academic Press.