Evaluation of therapeutic ultrasound application on equine tendinitis

Author(s)

Ana Guiomar Matos Santiago Reis

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2009-06-30

Examining board members

Raquel Yvonne Arantes Baccarin; Ana Liz Garcia Alves; André Luis do Valle de Zoppa

• Advisor: Raquel Yvonne Arantes Baccarin

Abstract

Equine athletes are frequently afflicted with locomotor injuries, especially racing horses. Tendinitis is a common problem of lameness in horse, and then the superficial digital flexor tendinitis (SDFT) is the greatest affected. Many of the tendinitis methods of treatment have an empirical basis; but none has proved an effective cure. The purpose of this study was to evaluate the effects of therapeutic ultrasound (TUS) on equine SDFT healing process. It was submitted 20 thoroughbred horses, mares and stallions, between two and nine years old, which were divided into three groups (G1, G2 and G3). The G1 was composed of eight horses; no tendinitis was induced, so they did not received any treatment. G2 and G3 were composed of six animals each one. All G2 and G3 forelimbs received 1.0 ml of collagenase (2.5 mg/ml) in the middle of SDFT. Healing process was monitored by clinical and sonographic evaluations. Randomly, one forelimb from each horse of G2 and G3 was treated with TUS performed at a frequency of 1 MHz on pulsed mode, an intensity of 0.5 W/cm2 (SATA - spatial average temporal average), for 5 minutes. After 15 treatment days, a tendon biopsy was performed on G2 tendons and protein expression for IGF-1, TGF-&beta;1 and PCNA were determined by immunohistochemistry. After 60 treatment days, a tendon biopsy was performed on G3 with the purpose of detecting and measuring the organization of collagen fibers through birefringence. Results showed no statistically difference for clinical examination on G2 and G3 treated and untreated tendons. Sonographic evaluation parameters such as isoechogenicity of tendon and lesion, diminution of lesion and tendon cross-sectional area, good axial alignment of collagen fibers was demonstrated by G3 treated limbs compared with normal tendon (P>0,05). The results showed no statistically difference between G1 and G2 treated and untreated tendons cells for PCNA expression. However, ultrasound-treated tendon cells (G2) were stained more strongly for TGF-&beta;1; whereas untreated tendon cells (G2) stained more strongly for IGF-1. The results showed a statistically difference (P<0.001) between G1 x G3 untreated tendons and between G3 treated and untreated tendons. Our results suggest that G2 TUS treatment time was not sufficient to improve tendon regeneration; although it modified IGF-1 and TGF-&beta;1 expression, accelerating tissue healing rate. In addition, G3 TUS protocol improved the arrangement and aggregation state of the collagen fibril, and promotes tendon regeneration. In conclusion, this TUS protocol is effective either to accelerate tendon healing or to improve the arrangement of the collagen fibril. (AU)