Cerebrovascular histopathology after intracarotid infusion of Gelfoam in the rat.

To evaluate the histopathology of Gelfoam on the cerebral vasculature, 42 Sprague-Dawley rats weighing 250 to 300 g received internal carotid artery infusions of 0.3 ml of Gelfoam solution (5 mg/ml) or normal saline (0.9%). The animals were killed at 1 hour, 5 hours, 3 days, 1 week, 2 weeks, and 4 weeks after the infusion. The brains were removed, sectioned, and stained with hematoxylin and eosin. Examination of brain sections revealed Gelfoam emboli lodged primarily in the small leptomeningeal arteries. At 5 hours after infusion, inflammatory cells were noted in the arterial walls with vessel occlusion. Further canalization of vessels was noted at 1 week. At 4 weeks, Gelfoam was not seen in the specimens. This study suggests that Gelfoam acts as an embolic agent in vessels over short periods of time with no residual inflammatory activity postinfusion.