Effects of nicotine on the formation of osteocalcin and osteoprotegerin and synthesis of its mRNA in MG63 osteoblast-like cell

Yang, Jun Ho; Park, Soo Byung

Abstract

The purpose of this study was to evaluate the correlation between nicotine and the activity of bone forming cell. MG63 osteoblast-like cells were used for this study. Several factors were examined including the proliferation of cell, alkaline phosphatase activity, the formation of osteocalcin and osteoprotegerin, and the synthesis of its mRNA. MG63 osteoblast-like cells were incubated for 1, 2, 3 and 6 days with nicotine added to the culture medium in 1.0 micrometer, 1.0 mM, 2.5 mM, 5.0 mM, 7.5 mM, and 10.0 mM concentrations. The proliferation of MG63 osteoblast-like cells was temporarily activated at the low nicotine concentrations. At high concentrations (>5.0 mM), however, it was suppressed. Alkaline phosphatase activity was suppressed in a dose-dependent manner as the concentration of nicotine increased. Osteocalcin decreased in a dose-dependent manner at high nicotine concentrations of more than 7.5 mM and the same result was show when the osteoblasts were treated with low concentrations for longer than 3 days. There was a difference in the influence of nicotine on the synthesis of osteocalcin mRNA and formation of osteocalcin itself at 1 and 3 days. Generally, osteoprotegrin notably declined in all experimental groups. However, the level of its mRNA inc-reased at high nicotine concentrations of more than 7.5 mM after 3 days and more than 5.0 mM after 6 days.