Abstract
Introduction
The objective of this study was to identify fat emboli in the arterioles of the femoral bone marrow by Scanning Electron Microscopy (SEM) after glucocorticoid administration.
Methods
Female adult rabbits weighing 3.5 to 4.0 kg received a single injection of prednisolone at a dose of 4 mg/kg body weight. The day after injection was designated as day 1. Control rabbits were injected with only physiological saline and euthanized on day 14. The femoral bone marrow was obtained on days 5, 8, and 14, and processed for SEM. Aortic blood serum was passed through a filter, and the filter was processed for SEM. Some SEM specimens were embedded in a plastic resin and sectioned for correspondence of SEM-photomicroscopy or SEM-TEM.
Results
In the controls, small fat globules were present in sinusoids and venules, but were absent from the arterioles. On day 5, fat globules were found in the lumina of both sinusoids and arterioles. Complete arteriolar occlusion was not found. On day 8, fat globules were often encountered in the venous and arteriolar lumina. Some small arterioles were completely occluded by fat emboli. On day 14, fat globules were present in the arterioles and some small and large arterioles were completely occluded. Blood drawn from the aorta contained fat globules in both the controls and rabbits injected with prednisolone.
Conclusion
A small amount of prednisolone induced the presence of fat globules in arterioles as early as day 5, complete occlusion of small arterioles on day 8, and occlusion of large arterioles on day 14. The source of fat globules and the mechanism of arteriolar occlusion were discussed.
