Effect of an AGE-modified type I collagen matrix on MC3T3E1 cell proliferation and spreading. MC3T3E1 osteoblastic cells were cultured on an unmodified collagen matrix or an AGE-collagen matrix for 24 hours at 37°C. Cell proliferation was evaluated by microscopically counting cells stained with Giemsa, at a magnification of 400X. Cellular spreading was also estimated microscopically, as the number of cells possessing at least two corners. Results are given as the number of cells counted per field, and are expressed as the mean ± SEM. Differences between collagen vs. AGE-collagen are as follows: * p<0.01; ** p<0.001.