Dermatophilus congolensis associated bronchopneumonia in an alpaca.

A severe, chronic, locally extensive granulomatous bronchopneumonia was diagnosed on post-mortem and histopathological examination of an adult alpaca. Dermatophilus congolensis organisms were isolated from the lungs and genotypic identification of aerobic culture was confirmed by sequence analysis of the entire 16S rDNA gene. This is the first report of D. congolensis-associated bronchopneumonia in any species.

Effects of tendon injury on uninjured regional tendons in the distal limb: An in-vivo study using an ovine tendinopathy model.

Following injury to a tendon little is known about potential for pathology to develop in other regional tendons from overloading or altered function. The aim of this study was to investigate the gene expression and histopathological changes that occur 1) within the deep digital flexor tendon (DDFT) after injury to the superficial digital flexor tendon (SDFT) and 2) within the flexor tendons (SDFT and DDFT) after injury to the extensor tendons. Merino wethers [Ovis aries] (n = 18) were divided into three equal groups and underwent either partial transection of the SDFT, complete transection of the extensor tendons or were left as non-operated controls. Tendons were harvested and sampled regionally for gene expression (real time PCR) and histologic analysis eight weeks after surgery. Transection of the SDFT resulted in increased expression of collagen III, versican, biglycan, lumican and MMP1 (P<0.026 for all genes) within the DDFT. There was no effect of transecting the extensor tendons on the expression of any gene tested in either the SDFT or the DDFT. The DDFT had elevated histopathology scores induced by transection of the SDFT, eight weeks previously. There were minimal histological differences in either the SDFT or DDFT after transection of the extensor tendons. Transection of the SDFT results in a mild, subclinical tendinopathy within the DDFT with potential implications on treatment and rehabilitation of SDFT injuries. Injury to the extensor tendons has minimal measured effect on the SDFT or DDFT.

Spatiotemporal variations in gene expression, histology and biomechanics in an ovine model of tendinopathy.

Flexor tendinopathy is a common problem affecting humans and animals. Tendon healing is poorly understood and the outcomes of conservative and surgical management are often suboptimal. While often considered a localized injury, recent evidence indicates that in the short term, tendinopathic changes are distributed widely throughout the tendon, remote from the lesion itself. Whether these changes persist throughout healing is unknown. The aim of this study was to document gene expression, histopathological and biomechanical changes that occur throughout the superficial digital flexor tendon (SDFT) up to 16 weeks post-injury, using an ovine surgical model of tendinopathy. Partial tendon transection was associated with decreased gene expression for aggrecan, decorin, fibromodulin, tissue inhibitors of metalloproteinases (TIMPS 1, 2 and 3), collagen I and collagen II. Gene expression for collagen III, lumican and matrix metalloproteinase 13 (MMP13) increased locally around the lesion site. Expression of collagen III and MMP13 decreased with time, but compared to controls, collagen III, MMP13 and lumican expression remained regionally high throughout the study. An increase in TIMP3 was observed over time. Histologically, operated tendons had higher pathology scores than controls, especially around the injured region. A chondroid phenotype was observed with increased cellular rounding and marked proteoglycan accumulation which only partially improved with time. Biomechanically, partial tendon transection resulted in a localized decrease in elastic modulus (in compression) but only at 8 weeks postoperatively. This study improves our understanding of tendon healing, demonstrating an early 'peak' in pathology characterized by altered gene expression and notable histopathological changes. Many of these pathological changes become more localized to the region of injury during healing. Collagen III and MMP13 expression levels remained high close to the lesion throughout the study and may reflect the production of tendon tissue with suboptimal biomechanical properties. Further studies evaluating the long-term response of tendon to injury (6-12 months) are warranted to provide additional information on tendon healing and provide further understanding of the mechanisms underlying the pathology observed in this study.