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Published on: August 2, 2024
Ultrasound Therapy With High-Pressure Pulses Is Effective to Reduce the Effects of Collagenase-Induced Tendinopathy
Carlos M Martínez1, Pedro LLontop2, Fernando Pérez-Sanz1
1Biomedical Research Institute of Murcia "Pascual Parrilla", Murcia, Spain.
Objective:
We propose an ultrasonic treatment for collagenase-induced tendinopathy in rat's Achilles tendon using pulses with a low number of cycles, high acoustic pressure and very low duty cycle.
Methods:
Twenty rats were used to perform the experiment. Four experimental groups of calcaneal tendons were studied: control (n = 6), sham (n = 4), collagenase-induced tendinopathy (n = 8) and ultrasound-treated collagenase-induced tendinopathy (n = 8). Surgical intervention was performed to expose the tendons prior to collagenase injection. A 1 MHz ultrasonic tansducer with a focusing lens was used. Ultrasonic treatments were used with an average total treatment time of 2.5 min, 20-cycle pulses, pressure amplitude p = 7 MPa, and 0.02% duty cycle. Histopathology of the samples was performed to evaluate nuclear density, acute inflammation, and signs of neovascularization. Collagen (types I and III), elastic fibers, and glycosaminoglycans were also analyzed.
Results:
No tendon involvement was found by the surgical process. Ultrasonic treatment is safe, as it does not affect healthy tendons. When collagenase infiltrated animals were treated with US, a clear predominance of type I collagen fibers and a similar collagen ratio profile to that observed in the control and sham groups was observed, with a higher density of elastic fibers compared to the control and sham groups and a significant increase in the density of glycosaminoglycans.
Conclusion:
The ultrasound treatment proposed reduces the effects of the artificial collagenase lesion to reach the basal level after 45 d.
