Uso de plasma rico em plaquetas em queimaduras Modelo experimental em ratos

Abstract

Burns are common and recurring events in the daily lives of medical care. There is a constant search to understand itsphysiopathology, in order to minimize its devastating results. Platelet-rich plasma (PRP) is a platelet concentrate with capacity of local release of multiple growth factors (FC) that accelerate healing. This study consists in two experiments: the first to validate an experimental model for the creation of standardized burns in size and depth and the second to evaluate the use of PRP in burns. The burns were achieved in an experimental burn model using an equipment that we developed and allows precise temperature control and in association with a innovative fixation technique that creates a constant pressure. Twelve rats per group underwent burns at 60oC, 70oC or 80oC for 10 seconds, with a device that we developed. Half of the animals of each group was killed on the third day and their wounds were analyzed by histology, and in the other half the wounds were measured and monitored until their closure. In the use of PRP in burns, second degree burns (SD), second degree burns with induced diabetes mellitus (SDD) and third degree burns (TD) were evaluated. Ninety animals were divided into three groups (SD, SDD, and TD) and in each one10 animals were treated, 10 animals served as controls, and 10 animals were used for PRP preparation. The wound areas were accompanied until the twenty-first day, when the animals were killed and skin biopsies were obtained. The results of the validation of the model show that the burns derived from 60oC were of superficial SD (28% of the dermis involved); for 70 °C they were deep SD (72% of the dermis involved); and for 80oC they were TD (100% of the dermis involved). Regarding the use of PRP in burns, it was observed that in the SD and SDD treated groups the wound closure was accelerated and there was reduction in the number of CD31, CD163, CD68, MPO, and TGF-β positive cells, and increasing of the number of MMP2 positive cells. The neoepidermis was thinner in control of both SD and SDD groups, and the granulation tissue was reduced in both control SDD and TD. The model used is safe and reliable to produce regular and uniform burns of varying diameters, by its ability of the fine control of temperature, by the animal positioning, and by its reproducibility. PRP appears to accelerate the healing of burns of SD and SDD, but not TD.