The effects of chitosan and chitin wound dressings in hairless dogs

The effects on wound healing of chitosan and chitin wound dressings were clinically andhistopathologically investigated using a split thickness wound in hairless dogs. Wound dressings used inthis study included examined were dried porcine skin (DP skin), cotton type chitosan (CT chitosan) andchitin fiber dressing (chitin FD). Clinically, there were no differences in wound healing among the sitestreated with chitosan, chitin and the untreated control sites. In contrast, DP skin and CT chitosan did notpromote wound healing. CT chitosan dressings induced severe inflammatory reactions. In the sitestreated with chitin FD, wound healing was delayed. Histopathologically, there were few differences inreepithelialization among the sites treated with chitosan, chitin and the WD-untreated sites. The sitestreated with DP skin received elastic fibers from DP skin. CT chitosan dressings had a deleterious effecton wound healing (reepithelialization and granulation). Dyskeratosis, congestion, hemorrhage, cellularinfiltration, intra- and intercellular edema were seen in the epidermis. Bleeding, infiltration ofinflammatory cells and mast cells, and edematous changes were seen in the dermis. In the sites treatedwith chitin FD, the invasion of mononuclear cells, mast cells and erythrocytes caused the retardeddevelopment of reepithelialization. It was concluded that chitosan and chitin had few deleterious effectson wound healing whereas DP skin, CT chitosan and chitin FD induced inflammation in the wound ofhairless dogs. In addition, it was clear that there are species differences in the skin reactions to wounddressings. These results suggested special care should be taken in veterinary clinical use of humanmedical wound dressings.