Role of collagen cross-linking on equine wound contraction and healing

Abstract

The present study was carried out to evaluate the effect of collagen cross-linking inhibition on equine wound contraction and healing. In five male adult donkeys, two full-thickness skin wounds (20 × 20 mm in diameter) were created on the lateral aspect of forelimbs, at the mid-point between the carpal and fetlock joints under general anesthesia. Two other wounds were created on the neck of each donkey symmetrically. Left-side wounds (test group) and right-side wounds (control group) were treated topically with beta-aminopropionitrile fumarate, 5 mg/ml, added to methyl cellulose gel and only methyl cellulose gel, respectively. Treatment of wounds were started at 24 h after wounding and continued every other day for ten successive days. The wounds were evaluated over a 3-week period. On days 0, 1, 3, 5, 7, 9, 12, 15, 18, and 21, digital photographs were taken of all wounds after careful shaving to visualize the wound margin. Rulers were held vertically and horizontally close to the wound as a reference. Epithelialization and granulation tissue formation were measured for each wound using Scion Image software. Percentage of the wound contraction, epithelialization, and healing were calculated for each wounds. At the end of the study, biopsy was taken from the center of each wound for hydroxyproline measurement and the same corner of each wound for histopathological examination. Macroscopic evaluation revealed significant differences in wound contraction and healing process between test and control groups in wounds located in neck (P 0.05). Significant differences were observed in the percent of wound contraction and healing between the test and control groups in wounds located in the forelimb (P 0.05). There were no significant differences between median of hydroxyproline levels of left and right wounds in forelimb and neck (P > 0.05). Histopathological examination revealed no significant differences between median of epithelialization, inflammatory infiltration, presence of dermal granulation tissue, fibroblast proliferation, arrangement of fibroblasts, collagen deposition, and collagen bundle formation scores in the specimens prepared from left and right wounds in forelimb and neck (P > 0.05). Our data demonstrated that collagen cross-linking could play a key role in equine wound contraction and healing at the limb and neck area.