Dimensão fractal das lesões provocadas por queimaduras e tratadas com fibrina rica em plaquetas autóloga em coelhos

Abstract

Burn injury is an important urgency and emergency in the medical clinic, caused by thermal, chemical, radioactive or electrical agents, which can totally or partially destroy the skin and its appendages, reaching deeper layers such as tendons, muscles and bones, whose classification varies according to the involvement and extent of the lesion. In view of these factors, the healing process consists of a perfect and coordinated cascade of cellular, molecular and biochemical events that interact for tissue reconstitution to occur. However, the use of dressings and antimicrobials are one of the options for local therapy. Experimental studies suggest new therapeutic options to solve possible problems in the healing process, autologous platelet-rich fibrin (aPRF) can be of great potential in complex wounds such as burns. The aim of the present study was to evaluate collagen production using the fractal dimension (FD) as a tool in experimentally induced burns in rabbits treated with or not with autologous platelet-rich fibrin. Ten adult male New Zealand rabbits were used, divided into two groups: C-control group (n=5), which received standard treatment for burns (5g of 1% silver sulfadiazine cream), T- treated group (n=5) with biomaterial. To induce the lesions, after general anesthesia of the animals, burns were made with a 30 cm long iron bar weighing 313gr previously heated in water at 920C, and applied for 10 sec/quadrant/rabbit. After this procedure, the animals received Tramadol hydrochloride (4.0mg/Kg, IM), twice a day for 3 consecutive days. Then a dressing was performed on all wounds using sterile rayon and adhesive dressing (Band Aid®). Changes were made after 24 and then every 72 hours until completing 30 days of the experiment. Skin biopsies were performed at 7, 14, 21 and 30 days post-injury using a 6 mm punch. All variables were assessed for normality using the Shapiro-Wilk test. The Kruskal-Wallis test was used to verify differences between treatments. Within-treatment differences were compared using the Student-Newman-Keuls test. Statistical differences were considered significant when P<0.05. The results showed a decrease in the FD values verified in the HE and Picrosirius stains, respectively, at 14 days after the burn in the group that received the aPRF(1.76±0.06; 1.81±0.03) in relation to the animals control (1.86±0.03; 1.76±0.02). It can be concluded that the treatment with autologous platelet-rich fibrin provided tissue improvemet and a production of collagen fibers, being a viable biomaterial for the treatment of burns.