To study temperature distribution, early histological changes, blood-brain barrier disruption and sequential changes in cerebral blood flow following hyperthermia ranging from 37 to 45°C in a new rat model of radiofrequency-induced localized cerebral hyperthermia.
Exposure duration: 30 min
|Exposure duration||30 min|
|power||10 W||unspecified||-||unspecified||20 W|
Significant histological changes and blood-brain barrier disruption were revealed in brain regions heated to 43°C and above. In the cortex heated to 41°C, the cerebral blood flow doubled 20 min after hyperthermia induction, and then returned to the pre-hyperthermic level. In the cortex heated to 43°C, the cerebral blood flow increased to 134% of the baseline level 10 min after hyperthermia induction, and then fell to reach its minimum level (31% of the baseline level). In the cortex heated to 45°C, the cerebral blood flow decreased immediately after hyperthermia induction to reach 10% of the baseline level.
The data suggest that hyperthermia-induced cellular injury in the central nervous system is associated with cerebral ischemia and the threshold temperature for such injury is 43°C. This model is useful for investigating the effects of hyperthermia on various cerebral functions.