RESUMO
Hemostatic effects of oxidized cellulose (Surgicel) are well known. Based on a possible similar effect of a sponge obtained after lyophilization of biosynthetic cellulose, two different experimental studies were planned. Phase I-Pieces of cellulose sponge were inserted into small provoked cortical wounds of twelve dogs. The time elapsed to obtain bloodstill after cortical damage and application of cellulose was observed in every dog, searching to detect any possible hemostatic effect of the material. The animals were sacrificed after 7, 30 and 90 days. An average time of 1 minute was elapsed until bleeding control was achieved. No clinical adverse effect was noticed. Microscopy showed histiocytic and mild foreign body reaction at 7 days, which diminished at 30 days. Almost no reaction surrounded the implant at 90 days. Lyophilized cellulose has a peculiar eosinophilic appearance, composed by thin irregular filaments which diminished their thickness with the time. At 90 days only sparse irregular cellulose filaments could be detected. Phase II-Small equal sponge fragments were inserted in the liver of twelve rats and observed 7, 30 and 90 days. At autopsy, small peritoneal adhesions were noticed at 30 and 90 days. Microscopy showed intense histioplasmocytic and foreign body reaction in all animals mainly at 7 days. In two animals, refringent intracellular cellulose particles were evident inside giant foreign body cells after 90 days. This fact evidences that cellulose can be reabsorbed by phagocytic phenomena when implanted in mammalians. A comparative group with other hemostatic material and the same method must be done to clarify the issue of hemostatic effects of this membrane.