FREEZING OSTEOBLAST CELLS ATTACHED TO HA DISCS AND GLASS COVERSLIPS: MECHANISMS OF DAMAGE

摘要

Damage mechanisms for osteoblast cells attached to hydroxyapatite discs and glass coverslips were comprehensively investigated. The inverse U shape curves of survival versus cooling rates were obtained with the maximum survival much lower than that of isolated osteoblast cells. Cell-cell, cell-matrix interaction may alter the cryobiological properties of cells. Attached cells were subject to more severe mechanical forms damage than isolated cells because attached cells have larger contacting area with ice and the three dimension movements of isolated cells make them more flexible than attached cells that can only deform in one dimension. Results show that solute effects result in cells injury at slow cooling rate (1°C/min), while extracellular ice, differential thermal contraction, and mechanical stresses damaged the cells at high cooling rate (5, 10, 20°C/min). No intracellular ice formation was found in this study. The immunostaining of actin filaments can qualitatively reveal the mechanical damage. It may be possible to quantitatively relate the cell survival to their spreading area.