thromboxane-b2 and Pressure-Ulcer

Because of their angular conformation, short hair, and thin skin, greyhounds are particularly subject to development of pressure ulcers. Greyhounds, therefore, can serve as a model to study pressure ulcers, either naturally occurring pressure ulcers or induced dermal pressure lesions. A method for inducing dermal pressure lesions was developed using a short-limb walking cast on one pelvic limb of the dog. Physical characteristics, dermal thromboxane B2 concentrations, and histopathologic changes were used to determine the severity of the lesions. Different lesion severities can be induced over the calcaneal tuberosity depending upon the amount of padding in the cast and the length of time the cast is in place. The technique for inducing a mild dermal pressure lesion is described.

Topics: Animals; Casts, Surgical; Disease Models, Animal; Dogs; Pressure; Pressure Ulcer; Thromboxane B2

Arachidonic acid metabolites have been implicated as mediators of progressive dermal ischemia. Decubitus ulcer formation results from chronic mechanical pressure on the skin which results in a diminished blood supply to the skin and underlying tissues. To evaluate the role of thromboxanes in pressure wounds, we measured TxB2, a stable metabolite of TxA2, in spontaneously occurring pressure wounds on Greyhound dogs. In pressure wounds in which the skin was showing early signs of pressure necrosis but was still intact, elevated TxB2 concentrations were found in healthy appearing tissues immediately adjacent to the pressure wounds, in the inner edge of the wounds, and in the center of the wounds. Significantly greater TxB2 concentrations (P less than 0.05) were found in the center of the intact wounds versus the TxB2 concentrations in the inner edge of the wounds or in healthy appearing tissues adjacent to the wounds. In pressure wounds in which the center of the wound had ulcerated or had an eschar, elevated TxB2 concentrations were found in tissues in the inner edge of the wounds and in healthy appearing tissues immediately adjacent to the pressure wounds. These results demonstrate the occurrence of elevated thromboxane concentrations in and around spontaneously occurring pressure wounds.

Topics: Animals; Biopsy; Dog Diseases; Dogs; Pressure Ulcer; Radioimmunoassay; Thromboxane B2