Histological and clinical evaluation of wound healing in pressure ulcers: a novel animal model

Objective: Pressure ulcers (PUs) are a major healthcare problem, commonly associated with older people, patients who are bedbound and patients with diabetes. The impact of PUs can decrease patients' quality of life, and lead to high morbidity and mortality rates. In this study, we aimed to describe a novel PU model that simulates pressure ulcers in humans to provide a research tool for new drug testing. Method: Diabetes was induced using streptozocin in 75 adult Sprague Dawley rats. To create the PU, skin was sandwiched between two magnets, one of them implanted below the panniculus carnosus muscle and the other above the skin. The model was tested on nondiabetic rats and diabetic rats, each with pressure ulcers, compared to nondiabetic rats with excisional wounds. Results: Results showed that the PU model in diabetic (p-value<0.000001) and non-diabetic rats (p-value<0.05) exhibited significantly delayed healing (no healing over 21 days) compared with the excisional wound that was completely healed by day 21. Conclusion: Diabetic rats showed significant changes in intact skin compared with non-diabetic rats, as well as a significant delay in the healing process compared with the non-diabetic group. By effectively impairing the skin contraction otherwise seen in the rats, and thereby delaying healing and making it similar to that seen in hard-to-heal PUs in humans, this model provides an effective tool for wound healing research.