Time-dependent Effects of Pressure during Preservation of Rat Hearts in an Isochoric System at Subfreezing Temperatures.

BACKGROUND: Isochoric freezing systems enable ice-free preservation of biological matter at subfreezing temperatures under the increased hydrostatic pressure.

OBJECTIVE: To examine the effects of pressure and exposure period on rat hearts preserved in an isochoric chamber.

MATERIALS AND METHODS: Rat hearts were preserved in the UW solution in isochoric chambers at temperatures from -2°C to -8°C and pressure from the atmospheric level to 78 MPa for up to eight hours, with and without the addition of glycerol. Hearts were evaluated via Langendorff perfusion and HE histology.

RESULTS: Hearts were compromised quickly as pressure increased, suggesting an acute time-pressure sensitivity. With the addition of 1 M glycerol, which reduces the pressure experienced at a given temperature, the survival time at -4°C was doubled.

CONCLUSION: The enhanced hydrostatic pressure encountered during isochoric preservation yields time-dependent negative effects on the heart, which can potentially be alleviated by the addition of a cryoprotectant.