C-fos expression of osteoblast-like MC3T3-E1 cells induced either by cooling or by fluid flow.

Fluid flow is one of the most potent mechanical stimulators for bone cells. Recent reports suggest that primary cilia as well as ion channels and related molecules play roles in the flow detection by kidney epithelial cells. We asked if there is any commonality between kidney and bone cells in flow detection. Primary cilia of cultured osteoblastic cell line MC3T3-E1 were detected by fluorescence staining of acetylated alpha-tubulins. The cells responded to fluid flow, generated by manual rocking of flasks, and expressed c-fos gene. Moreover, the cells were found to respond not only the flow but also cooling of the culture fluid, with a simple technique to keep temperature precisely. It was suggested that bone and kidney cells might share certain similarity in flow detection mechanisms.

Evaluation of cell culture flasks designed for experiment under altered gravity-vector conditions.

Cell culture flasks applicable for altered gravity conditions, such as centrifugation, clino-rotation or microgravity in space, were manufactured for trial. The flask has flat polystyrene surface for monolayer culture and gas-permeable film window on the opposite face. The space in-between consists the culture chamber to be filled with liquid medium. To reduce the water loss and bubble formation in the culture fluid, another gas permeable window was placed on top to form a space where distilled water may be filled. The double-decker culture flask can be used for both space and ground-based experiments in common.