Proposta de protocolo para a utilização de ultrassom terapêutico de 3Mhz pulsado no processo de cicatrização de feridas cutâneas experimentais em ratos wistar

Abstract

Introduction: In Brazil, wounds are a serious public health problem, due to the large number of patients with changes in skin integrity, although the records of these treatments are scarce. In attempt to minimize tissue healing time, several animal studies have been presenting the use of therapeutic ultrasound as a coadjuvant factor. However, there is no standardization of doses for use of this therapy in cutaneous wounds. Objective: To propose protocol for treatment of experimental cutaneous wounds by means of 3 MHz pulsed therapeutic ultrasound through the intensities 1,0 W/cm2, 1,5 W/cm2, 2,0 W/cm2. Material and method: This is an experimental and randomized study. Sixty male Wistar rats were used. The animals were anesthetized and submitted to skin excision surgery through a dermatological punch number 8. The animals were randomly randomized into 4 different groups being: control group; TA (1,0 W/cm2); TB (1,5 W/cm2) and TC (2,0 W/cm2). We used a 3 MHz UST, pulsed with 20% pulse with, 100Hz, for 2 minutes, daily. The control group was manipulated with the device switched off. Each group was evaluated in 3 different time frames: 3td, 7th and 15th postoperative days. Biometric, morphometric and stereological evaluations were performed. For the statistic, the PRISM 6.0 software was used with the TWO-WAY ANOVA test with BONFERRONI post-test considering p <0.05. Results: In the evaluation of the variables for retraction of the wound area, percentage of retraction, thickness of keratin and epithelium, there was no difference between the control group and the groups irradiated with TUS. In the stereological analysis, the volume density and area of macrophages decreased as the intensity tested was increased. The intensity of 2,0 W/cm2 increased the proliferation of fibroblasts suggesting a hypertrophic scar. In the qualitative analysis of collagen and elastic fibers, the groups treated with UST show a better distribution of fibers in the dermis bed. Conclusion: In this experimental model, the protocol for the use of therapeutic ultrasound it leads to an organization of collagen fibers, elastic fibers and adequate migration of fibroblasts when treated with intensity between 1,0 and 1,5 W/cm2 however does not reduce the healing time of cutaneous lesions.