Effects of hyperthermia on normal or neoplastic rat liver

An experimental study was conducted in rats to evaluate the sensitivity of the liver to infrared hyperthermia. A 15-min hyperthermia session treating only the liver was done in rats with a normal hepatic parenchyma and in rats with hepatocarcinoma induced by chronic 3'-diethylaminoazobenzene intoxication, at various ranges of intrahepatic temperature. In normal rats, 40-42 degrees C hyperthermia was well tolerated, but the mortality rate increased when the intrahepatic temperature exceeded 42 degrees C. In rats with tumors, a 40-42 degrees C hyperthermia session was well tolerated in case of small tumors, but resulted in a high mortality rate in case of large tumors. In all cases, death occurred as a consequence of liver injury. This study using a simple method of hyperthermia defines the thermosensitivity of the neoplastic or normal rat liver and provides a basis for further investigations on the effect of hyperthermia on experimental liver tumors.