The effects of hydrostatic pressure on cell viability and function are complex and have not been fully clarified. We have reported that astrocytes and A172, an adherent cell line, show higher viability when preserved for 4 days at about 1.6-2.0 MPa than at ambient pressure. In this study, we investigated the effects of solution environments, wide range of hydrostatic pressures (0.1-30 MPa) and temperatures (4, 10, 15, 20, 25 and 37ºC), on the viability and function of rat primary astrocytes after 4 days preservation.
The cell suspension (1Χ106 in 300 μl DMEM media) was placed in a silicon tube (5-mm inner diameter, 7-mm outer diameter) and sealed on both sides by Teflon rods (6-mm diameter, 7-mm length). The inner container was placed in a stainless steel pressure vessel and filled with water. After preservation under each condition, viability were determined using Muse Count and Viability Kit (Merck Millipore, Darmstadt, Germany). Cellular functions, the change of amount of proteins (Glial fibrillary acidic protein, Glutamine synthetase and Actin), were assessed by Western blot analyses.
The viability of astrocytes after 4 days preservation was strongly influenced by preservation temperature at ambient pressure, and showed the high viability at 10-20 ºC. Also, adhesive and proliferative capacities of cells after 4 days preservation at these temperatures were similar to the cells before preservation. Next we studied the pressure effect on viability of astrocytes. At 10 and 15°C, the viability after 4 days preservation was decreased with increasing pressure up to 30 MPa. The other hand, the survival rates preserved at 20 and 25°C was slightly convex upward and significantly increased with increasing pressure up to 30 MPa. These results indicated that the astrocytes preserved under high hydrostatic pressure can be remained in good condition by suppressing the effect of the temperature change. Furthermore, we explain the results of Western blot analyses in detail on the day.