AIMThe redox dynamics of the rat liver in the whole body hyperthermia was measured by the decay rate of the ESR spectra used carbamoyl-PROXYL as a spin probe.

METHODSFifty-two Wistar male rats were randomly assigned to four groups and each group was subjected to only one of the following treatments: heat stress (HS group), anesthesia without hyperthermia (control group), pretreatment with MPG (MPG + HS group) and pretreatment with saline (No-MPG group). The solution of carbamoyl PROXYL was added to rat liver homogenate from 0, 1, 2, 6 and 24 h after heating at concentration of 0.1 mmol/L. sequentially the ESR spectra of the samples were immediately recorded by X-band ESR spectrometer.

RESULTSCompared with the control group, the signal decay rate was increased gradually after heat treatment, and attained the maximum at 2 h, and then returned to the normal level at 24 h. This signal intensity effect was reduced by MPG pretreatment.

CONCLUSIONGeneration of reactive oxygen species in liver may be induced by heat stress.