Accelerating effects of chitosan for healing at early phase of experimental open wound in dogs

Chitosan is a polymeric beta(1 --> 4) glucosamine (2-amino-2-deoxy-D-glucos e) and N-acetyl-D-glucosamine (2-acetamido-2-deoxy-D-glucose) which has bee n reported as a wound healing accelerator. In order to evaluate the efficac y of chitosan as an accelerator of wound healing, experimental open skin wo unds were made on the dorsal side in three normal beagles. Cottonfiber-type chitosan (degree of acetylation = 18%) was applied for 15 days, and the pr ocess of wound healing was evaluated histologically and immunohistochemical ly. On day 3 postwounding, the chitosan-treated wounds showed histologicall y severe infiltration of polymorphonuclear (PMN) cells and an increase in e ffusion compared with that in the control. Granulation was more pronounced by the chitosan treatment on day 9 and 15 postwounding. Immunohistochemical typing of collagen I, III and IV showed increase of the production of type III collagen in the chitosan group. The appearance of mitotic cells occurr ed numerously in the control on postwounding day 3, and in the chitosan gro up on postwounding day 6, These results suggest chitosan to be having a fun ction in the acceleration of infiltration of PMN cells at the early stage o f wound healing, followed by the production of collagen by fibroblasts. (C) 1999 Elsevier Science Ltd. All rights reserved.