The effects of topical collagen treatment on wound breaking strength and scar cosmesis in rats.

Collagen is the most abundant protein in the body, and is responsible for skin strength and is a key player in tissue healing. Various applications of collagen, such as a filler for cosmetic enhancement of skin wrinkles and regeneration of youthful appearance, have been proposed. When used appropriately, collagen has been shown to be safe and reliable. There is suggestive evidence that the topical application of collagen enhances wound healing in human and animal models (1). Glasgold et al (1) reported subjective enhancement of wound closure and cosmesis in an uncontrolled clinical experience involving 12 patients who underwent Mohs micrographic surgery. They correlated their finding with studies performed in guinea pigs showing rapid infiltration of fibrous tissue and endothelial cells. In contrast, Becker et al (2) prospectively examined 39 patients and found no evidence of enhanced wound closure or final cosmetic results with the topical use of bovine collagen in facial wounds. Importantly, the results of these studies were based on subjective outcomes and were not blinded or randomized. In addition to its cosmetic uses, collagen has also been shown to be useful as a vehicle for the administration of growth factors to wounds in animal models. A purified and hypoallergenic viscous suspension of collagen has been shown to facilitate a slow release mechanism of dissolved growth factors without itself interfering with early wound healing in rats (3). Bovine collagen type I was further studied in an oral surgery application in dogs. Al-Kateeb et al (4) found that collagen-treated wounds demonstrated an improved rate of early wound healing and had a topical hemostatic effect at the time of application, with no adverse reactions to the collagen treatment, consistent with the literature. Pharmacological effects of collagen on wound healing, including a hemostatic effect, interaction with platelets and fibronectin, and effects on fluid exudates, have been suggested (5–8). The hypoallergenic and safe properties of collagen, and its potential use as a vehicle for topical application to wounds, are very attractive for experimental and future clinical applications. There is, however, controversy regarding the long-term effects of collagen on wound healing and cosmesis. The present study aimed to determine the effects of collagen on early and late wound healing in the rat incisional skin model.