Effects of heparin and hyperbaric oxygenation on necrosis reduction in an animal model for degloving injuries

Abstract

Objective: to evaluate the efficacy of the treatment with hyperbaric oxygen therapy or with topical and intralesional heparin in an animal model of degloving lesions. Methods: we conducted an experimental study with adult, male Wistar rats submitted to degloving of the left hind limb and divided into four groups according to the treatment: Group 1 (control) - without treatment; Group 2 (Heparin) - intralesional application at the time of surgery and topically, in the postoperative period, with heparin spray 10,000IU/mL; Group 3 (hyperbaric oxygenation) - daily sessions of 30 minutes in a hyperbaric chamber with 100% oxygen and 2 ATA pressure; Group 4 (positive control) - administration of a single dose of 45 mg/kg of intraperitoneal allopurinol. On the seventh day, we killed the animals, removed the cutaneous flaps and measured the total and necrotic areas, as well as computed the percentage of necrotic area. Results: the mean percentage of necrosis in the control group was 56.03%; in the positive control group it was 51.36% (p<0.45); in the heparin group, 42.10% (p<0.07); and in the hyperbaric oxygen therapy group, 31.58% (p<0.01) . Conclusion: both hyperbaric oxygen and heparin therapies were effective in reducing the percentage of necrosis in the model studied, although only the hyperbaric oxygenation showed statistical significance.

Effect of hyperbaric oxygenation on random rat skin flaps vascularization

“…In a previous study, an increase in the viability of the random flap was noticed attributed to the use of HBO for seven days after the operation. This positive effect was probably due to the maintenance of tissue oxygen pressure in poorly perfused and ischemic tissue areas, until the blood flow in the flap increases due to the response of the tissue to angiogenesis 1 , 25 . It should be mentioned that angiogenesis is modulated by growth factors that are located in endothelial cells and extracellular matrix 30 , 31 .…”

“…At the limits of the delimited skin area, an incision was made on the three edges of the delimited area with a scalpel blade (no. 15), maintaining the continuity of the flap along its cranial portion, according to the model proposed by McFarlane and modified by our group 1 . The flap was composed of epidermis, dermis, adipose tissue, and panniculus carnosus (skeletal muscle), which raised and was maintained fixed only by its pedicle (cephalic portion of the rectangle).…”

“…Optimizing the feasibility of surgical flaps has always been a challenge in medical science. A viable flap implies a decrease in post-surgical morbidity, a faster recovery of patients and a lower cost to the healthcare system involved 1 - 7 .…”

“…Thus, HBO is based on the dilution of oxygen in body fluids, which are usually under a pressure between 2 and 3 atmospheres absolute (ATA). For safety purposes, the hyperbaric chamber must withstand up to 1.5 times the maximum working pressure (4.5 ATA) 1 , 2 , 4 , 6 .…”

“…HBO has been proposed for the treatment of several models of compromised flaps and, when instituted immediately after surgery, it can mitigate the progression of ischemia, which leads to apoptosis and necrosis 1 , 3 , 13 . There is experimental evidence regarding hyperbaric oxygenation in various types of tissues and organs 14 - 23 .…”