Effect of hyperthermic preconditioning on cold preserved rat portal veins

Little information is available regarding the effect of cold storage and hyperthermic preconditioning on the contractile responses of hepatic vessels. We then studied, after cold preservation, the in vitro contractile responses of rat portal veins (RPV) isolated from normal rats or from rats previously subjected to hyperthermia.

Rats were or were not subjected to hyperthermia 24 h before the RPV isolation. Then, RPV were stored at 4 degrees C in Krebs-Henseleit bicarbonate (KHB) or University of Wisconsin solution or conserved at 20 degrees C in KHB solution. Control RPV were tested after rat sacrifice.

The contractile responses were importantly decreased in RPV conserved at room temperature. The morphology of the vessels was altered and the heat shock protein 70 (Hsp70) protein expression disappeared. These abnormalities were prevented by cold preservation. The type of preservation solution did not interfere with the beneficial effect. Hyperthermic preconditioning increased the expression of Hsp70 protein in freshly isolated and cold preserved RPV but decreased the contractile responses. In RPV conserved at room temperature, hyperthermic preconditioning further worsened the decreased contractile response.

Thus, hyperthermic preconditioning, which is beneficial in protecting hepatic injury following cold preservation, alters the contractile responses of RPV.