Non-enzymatic glycosylation of a type I collagen matrix: effects on osteoblastic development and oxidative stress

Background: The tissue accumulation of protein-bound advanced glycation endproducts (AGE) may be involved in the etiology of diabetic chronic complications, including osteopenia. The aim of this study was to investigate the effect of an AGE-modified type I collagen substratum on the adhesion, spreading, proliferation and differentiation of rat ste sarcoma UMR106 and mouse nontransformed MC3T3E1 ste blastic cells. We als studied the role of reactive oxygen species (ROS) and nitric oxide synthase (NOS) expression on these AGE-collagen mediated effects. Results: AGE-collagen decreased the adhesion of UMR106 cells, but had no effect on the attachment of MC3T3E1 cells. In the UMR106 cell line, AGE-collagen als inhibited cellular proliferation, spreading and alkaline phosphatase (ALP) activity. In pre ste blastic MC3T3E1 cells (24-hour culture), proliferation and spreading were significantly increased by AGE-collagen. After ne week of culture (differentiated MC3T3E1 ste blasts) AGE-collagen inhibited ALP activity, but had no effect on cell number. In mineralizing MC3T3E1 cells (3-week culture) AGE-collagen induced a decrease in the number of surviving cells and of extracellular nodules of mineralization, with ut modifying their ALP activity. Intracellular ROS production, measured after a 48-hour culture, was decreased by AGE-collagen in MC3T3E1 cells, but was increased by AGE-collagen in UMR106 cells. After a 24-hour culture, AGE-collagen increased the expression of endothelial and inducible NOS, in both ste blastic cell lines. Conclusions: These results suggest that the accumulation of AGE on bone extracellular matrix could regulate the proliferation and differentiation of ste blastic cells. These effects appear to depend on the stage of ste blastic development, and possibly involve the modulation of NOS expression and intracellular ROS pathways.