Efeito do ultrassom terapêutico de baixa intensidade em fratura induzida em tíbia de ratos

Abstract

OBJECTIVE: To analyze the possible effects of low-intensity ultrasound on induced tibia fracture of rats in a dose commonly used in physical therapy treatments. METHODS: Twenty male Wistar rats were divided into two groups with 10 animals each. In the ultrasound group (USG), the animals were submitted to bone fracture and treatment with therapeutic ultrasound (TUS). Ultrasonic parameters are: frequency of 1.0 MHz, intensity of 0.2 W/cm2, pulsed mode at 20%, applied in stationary form during 10 minutes on the fracture region, for five weeks. The control group (CG) was submitted to bone fracture but not treated with ultrasound. RESULTS: The radiographies showed better consolidation in USG compared to CG. The statistical tests for alkaline phosphatase and serum calcium did not show significant difference between groups. CONCLUSION: According to this study, TUS, applied with these parameters (not commonly used for bone therapy) accelerates bone healing, confirmed by radiography, yet the biochemical analysis was not conclusive. One reason for this inconsistency may have been some inadequacy of the biochemical protocol, currently under investigation. Level of Evidence II, Prospective comparative study.

The influence of low-intensity physiotherapeutic ultrasound on the initial stage of bone healing in rats: an experimental and simulation study

“…Prior to fracture induction, the rats were anesthetized with intraperitoneal ketamine (80 mg/kg) and xylazine (15 mg/kg) solution [2, 8] at a dose of 0.6 mL per 100 g body weight. After sedation, the rats were placed in the lateral decubitus position and then subjected to fracture of the middle one third of the diaphysis of the right tibia of the hind limb, using the equipment previously described [2].…”

“…After sedation, the rats were placed in the lateral decubitus position and then subjected to fracture of the middle one third of the diaphysis of the right tibia of the hind limb, using the equipment previously described [2]. Afterwards, the rats were placed in cages, with a maximum of four rats per cage, and subjected to analgesic therapy during the entire experimental period (200 mg/kg paracetamol dissolved in water).…”

“…Even though it is one of the most rigid and resilient substances in the human body, bone tissue is constantly exposed to conditions, such as injury or fracture, that may affect its structural integrity [1, 2]. The occurrence of a fracture triggers a complex process of healing to restore bone mechanics and functional integrity [1, 3].…”

“…Sometimes, there can be complications in this process, resulting in retardation of fracture union with the risk of pseudoarthrosis [5] and other consequences, such as long and painful treatment, missed work, reduction in patients’ quality of life and general well-being, and increased public health-care expenditures [6, 7]. Thus, efforts to determine treatments that accelerate the bone consolidation process are justified [2, 8]. …”

“…An investigation of this potential use should include careful steps to enable standardization of the duration and intensity of irradiation required for effective treatment. To date, no conclusive investigation on the evaluation of cellular and biochemical mechanisms triggered by TUS [2, 9] has been reported. The present study analyzed the radiographic, biochemical, and histological effects of TUS at an intensity of 40 mW/cm 2 in induced fractures of rat tibias with the objective of evaluating the effect of ultrasound intensity provided by common TUS equipment on the initial stage of fracture healing.…”