Figure 3

Von-Kossa Staining and Mineralized Nodules Formation. At 3 hours after differentiation medium, little Von-Kossa positive staining colony was found in the culture. The Von-Kossa positive staining colonies first appeared at the 1^st day's culture of control groups, and then progressively increased as the culture period passed, and attained a significant degree at the 7^th day's culture. When osteoblasts cultured with 10 mM concentration of caffeine, the appearance of Von-Kossa staining was decreased and the residual cells lost their reaction to Von-Kossa staining.