[Microvascular injury in hyperthermia by injecting warm water using noradrenaline into tumor feeding artery-induced tumor necrosis of Walker-256].

Wistar rats were injected sc, with cells from Walker-256, which is resistant to hyperthermia. When hyperthermia was achieved by immersing the tumor at 44 degrees C for 60 minutes after injecting MMC (0.5 mg/kg), tumor growth was markedly suppressed in D-8 group, which formed many tumor vessels, but was not suppressed in D-4 group, which did not still form them. In D-8 group, 10 ml of warmed water at 44 degrees C using 0.001% of noradrenaline injected into tumor feeding artery after chemotherapy showed enhanced anti tumor effects in established vascularized tumor. These two methods of hyperthermia caused vascular endothelial cell damage that preceded tumor necrosis. These results suggest that hyperthermia exerted an antitumor effect in this tumor model by damaging tumor blood vessels, which led to ischemic tumor necrosis.