Cerebral arterial fat embolism in the rabbit

Abstract

This study was designed to measure the effects of cerebral arterial fat embolism on cerebral blood flow and function. Rabbits were injected via the left internal carotid artery with the neutral triglyceride triolein. Left cerebral blood flow was measured by laser Doppler flowmetry, and left sided brain function by electrocorticogram and cortical somatosensory evoked responses following electrical stimulation of the forepaw. Readings were taken for 2 h before injection to establish a baseline, and for 3 h after injection. Cerebral blood flow was significantly decreased at 45 min after the injection of the lipid, then progressively decreased further to approximately 50% of baseline after 2 h, at which level it remained for the last hour of the experiment. The electrocorticogram was rapidly, but transiently, suppressed. The evoked responses did not differ from baseline at each of the time points measured. Using 125I-triolein, 2.49% of the injected dose was measured in the brain 3 min after injection. The results show that in this rabbit model of cerebral arterial fat embolism only a small percentage of injected lipid passes into the brain, but this is sufficient to cause a reduction in cerebral blood flow over the following 2 h. The evoked responses never alter significantly from baseline values.