Cerebral radioprotective effects of high-dose pentobarbital evaluated in an animal radiosurgery model.

AbstractBecause pentobarbital has been shown to reduce cerebral toxicity to single-fraction whole brain irradiation in a rat model, we sought to evaluate its cerebral radioprotective effects for stereotactic radiosurgery. We hypothesized that concurrent high-dose pentobarbital anaesthesia (50 mg kg–1) during irradiation could delay or prevent the onset of radiation necrosis within the radiosurgical volume. Six rats were placed in pentobarbital or control groups, irradiatedand then evaluated at different intervals (60, 100; 750, 365 days; total = 48 animals studied). All rats had 100 Gy radiosurgery to the right frontal brain region (a threshold dose for focal necrosis at 90 days). The radioprotective effects of pentobarbital were compared to ketamine anaesthesia (control) and evaluated for observed focal necrosis, size of necrotic lesion, blood vessel alterations, and to changes in cell nuclei. There was no difference between groups in the numbers of rats with necrosis at 100 days (p = 0.72), at 150 days ...