892 AJVR, Vol 66, No. 5, May 2005 I n horses, ligaments are frequently affected with lesions that result in degenerative and inflammatory changes. The healing of these lesions is often unsuc- cessful with regard to restoration of the morphologic and functional characteristics of the ligament, thereby compromising the future athletic performance of or increasing the risk of recurrence of lesions in the affect- ed horses. 1 Treatment of suspensory ligament desmitis in ath- letic horses is controversial. Various treatments have been proposed for the treatment of suspensory liga- ment desmitis, including rest, controlled exercise pro- tocols, intralesional injections, administration of anti- inflammatory agents, and corrective shoeing; however, these treatments are commonly associated with unsat- isfactory results and high recurrence rates, especially when used in horses with hind limb suspensory liga- ment desmitis. 2,3 New treatments such as extracorporeal shock wave therapy (ESWT) may represent an option for the treatment of suspensory ligament desmitis in horses, according to some researchers. 3-5 In support of this claim, results of 1 study 4 indicated that ESWT-treated lesions in horses with collagenase-induced suspensory ligament desmitis healed faster than non–ESWT-treat- ed lesions, as evaluated ultrasonographically. Results of another recent study a in rats also suggest that ESWT is associated with an increase in the production of trans- forming growth factor β-1 (TGFβ-1), with concomi- tant chemotactic and mitogen effects on osteoblasts. Few controlled studies have been performed to investigate the experimental use of the extracorporeal shock waves in horses. The purpose of the study reported here was to evaluate the effects of ESWT on affected ligaments in the hind limbs of horses with experimentally induced suspensory ligament desmitis by use of ultrasonographic, ultrastructural, and immunocytochemical techniques. Materials and Methods This study was approved by the Ethics in Animal Experimentation Committee of UNESP-Botucatu. Ten adult horses (4 geldings and 6 mares) were included in the study. Prior to induction of suspensory desmitis, each horse underwent an initial clinical lameness and ultrasonograph- ic examination of the hindlimbs. Suspensory desmitis was induced in both hind limbs of each horse by use of 2 colla- genase b injections/limb administered 2 weeks apart. For Received April 16, 2004. Accepted August 18, 2004. From Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista, Botucatu, SP, Brazil CEP 18618-000 (Caminoto, Alves, Amorim, Thomassian, Hussni, Nicoletti); and Centro Universitário de Rio Preto, Faculdade de Medicina Veterinária, São José do Rio Preto, SP, Brazil CEP 15061-718 (Caminoto). This manuscript represents a portion of a thesis submitted by the first author to the Veterinary Medicine College, Universidade Estadual Paulista, Botucatu, SP, Brazil, as a partial fulfillment of the require- ments for a Master of Science degree. Supported by Fundação de Apoio à Pesquisa do Estado de São Paulo– Brazil (research support foundation of São Paulo state). Address correspondence to Dr. Caminoto. Ultrastructural and immunocytochemical evaluation of the effects of extracorporeal shock wave treatment in the hind limbs of horses with experimentally induced suspensory ligament desmitis Elisa H. Caminoto, DVM, MS; Ana Liz G. Alves, DVM, PhD; Renée L. Amorim, DVM, PhD; Armen Thomassian, DVM, PhD; Carlos A. Hussni, DVM, PhD; José Luis M. Nicoletti, DVM, PhD Objective—To evaluate the effects of extracorporeal shock wave therapy (ESWT) on affected ligaments in the hind limbs of horses with experimentally induced suspensory ligament desmitis by use of ultrasono- graphic, ultrastructural, and immunocytochemical techniques. Animals—10 horses. Procedure—Suspensory ligament desmitis was induced in both hind limbs of each horse by use of 2 collagenase injections (administered 2 weeks apart) in each suspensory ligament. Two weeks after the second injection, the right hind limb of each horse was treated with ESWT (3 treatments at 3-week intervals); the left hind limb was not treated (control limb). Periodically during the study, the healing process was monitored ultrasonographically and the proportions of ligaments affected with lesions were assessed. Four weeks after the last ESWT treatment, biopsy specimens were collected from all ligaments for ultrastructural evaluation and immunocytochemical analysis of transforming growth factor β-1. Results—The difference in the proportion of the lesion- affected ligament between ESWT-treated and control limbs was significant (P < 0.05) from 3 weeks after the second ESWT treatment to the end of the study. Compared with control ligaments, ESWT-treated liga- ments had more small, newly formed collagen fibrils and greater expression of transforming growth factor β-1 4 weeks after the last ESWT treatment was administered. Conclusions and Clinical Relevance—Results have indicated that ESWT appears to facilitate the healing process in horses with experimentally induced hind limb suspensory ligament desmitis. (Am J Vet Res 2005;66:892–896) Unauthenticated | Downloaded 08/13/22 05:06 PM UTC