[Growth of the hoof horn in horses with chronic laminitis]. / Das Hornwachstum bei der chronischen Hufrehe des Pferdes.

UNLABELLED: Objective of the study was to investigate whether a correlation between rotation and/or sinking of the third phalanx (P3) and changes of horn growth on the hoof wall exists. MATERIAL AND METHODS: In 117 hooves of euthanatized or slaughtered horses with chronic laminitis the rotating angle to palmar/plantar and medial/lateral and a sinking of P3 were assessed on radiographs. Defined distances were measured on the dorsal hoof wall as well as in the heel to assess the horn growth of a hoof. On the basis of saw cuts of the hooves, the course of the horn tubes was judged. RESULTS: A rotation angle of approximately 8° was found to predict a change in the direction of the growth of the hoof horn at the dorsal and the lateral hoof wall. In addition, a correlation between the rotation angle of P3 and the length of growth of the hoof could be highlighted. A greater angle could lead to a larger interruption of the dorsal horn growth; meanwhile the palmar/plantar horn growth appeared to be independent. A correlation between a medial/lateral rotation of the pedal bone and the length of the horn was not observed. CONCLUSION: The direction change of the horn tubes might cause a decrease of the visible length growth of a chronic laminitic hoof. Therefore, it appears to be important to differentiate between the externally visible length of the hoof and the real growth of the horn. Apparently, the amount of horn produced is the same on the dorsal hoof wall and in the heel. In horses with moderate laminitis the horn tubes on the dorsal wall were lying in folds, with the consequence of a decreased visible length growth. Only the formation of wrinkles of the horn tubes on the dorsal hoof wall reduced the visible wall length. Formation of wrinkles of the horn tubes in the heel could not be observed. Interestingly, the results of this study show that the lateral rotation of P3 does not promote the formation of wrinkles of the horn tubes along the lateral or medial hoof wall. CLINICAL RELEVANCE: According to our results, a resection of the dorsal hoof wall might be a sensible therapeutic approach in horses with chronic laminitis showing a rotation of P3 of at least 8°.

Determination of MMP-2 and -9 activities in synovial fluid of horses with osteoarthritic and arthritic joint diseases using gelatin zymography and immunocapture activity assays.

REASON FOR PERFORMING STUDY: Matrix metalloproteinases (MMPs)-2 and -9 activities have been found elevated in synovial fluid from various joint diseases in man. However, in the horse few data are available. OBJECTIVES: To explore the clinical significance of MMP-2 and -9 activities in synovial fluid of horses with different forms of joint diseases. METHODS: Gelatin zymography and MMP-2 and -9 immunocapture activity assays were applied on synovial fluids from control joints and joints with aseptic joint disease (AJD) and septic arthritis (SA). Additionally, MMP-2 and -9 activities were measured in samples from SA to monitor the disease process. RESULTS: Zymographic analysis revealed that samples from AJD and SA contained significantly increased latent MMP-2 activity compared to controls. Samples from SA showed significantly increased monomeric latent MMP-9 activity compared with all other affected joints and controls. Trace amounts of MMP-9 activity, due to the active and dimer form, were detected in samples from SA; however, these bands were absent in samples from AJD and controls. Using immunocapture activity assays, MMP-2 and -9 activities were found to be significantly elevated in joints from SA compared to controls and AJD samples. MMP-2 activity in samples from AJD was significantly increased compared to controls. Both MMP activities decreased in the joints from SA in the course of successful therapy. CONCLUSIONS: Data from zymographic analysis confirmed that MMP-2 and -9 were elevated in equine joint diseases. Immunocapture activity assays have been shown to be suitable for the quantitative determination of MMP-2 and -9 activities in synovial fluid of horses. Both MMP-2 and -9 activities seem to be useful to indicate SA, and MMP-2 activity might be a suitable marker for AJD. POTENTIAL RELEVANCE: These findings encourage the potential use of MMP-2 and -9 as additional aids to clinical investigation. Further work is required to validate the clinical significance of MMP activities in the progress of different joint diseases in horses.

Measurement of equine myeloperoxidase (MPO) activity in synovial fluid by a modified MPO assay and evaluation of joint diseases - an initial case study.

The aim of this study was to develop a specific myeloperoxidase (MPO) activity assay in the synovial fluid of horses and investigate whether MPO activity is increased in different forms of joint diseases. Synovial fluid samples were taken from affected joints from horses with osteoarthritis, chronic non-septic arthritis and septic arthritis, and from healthy control horses. MPO activity was measured using a specific modified o-dianisidine-assay containing 4-aminobenzoic acid hydrazide as a potent and specific inhibitor of the MPO. This assay is characterized by high reproducibility. The results reveal only a slight elevation of MPO activity in the synovial fluid of horses with osteoarthritis and chronic non-septic arthritis. However, in the cases of septic arthritis a significant increase in MPO activity was found when compared to the controls. In conclusion the first field study suggests that synovial fluid MPO may be used as a marker for septic arthritis in horses.

[Scanning electron microscopic findings of the navicular bone and deep flexor tendon in podotrochlosis of horses]. / Rasterelektronenmikroskopische Befunde an Strahlbein und tiefer Beugesehne bei der Podotrochlose des Pferdes.

In 25 adult horses the podotrochlea of 49 forelimbs was examined by means of light and electron microscopy in order to correlate clinical and morphological findings. According to the clinical diagnosis the animals were divided into three groups: lameness due to syndrome of podotrochlosis (group 1) or due to tendopathy (group 2) and horses without lameness (group 3). The most striking pathological findings of the navicular bone and the opposite surface of the deep flexor tendon were found in horses with podotrochlosis, consisting of loss of cartilage and tendon matrix with denudation of collagen fibrils, superficial degeneration and necrosis, focal occurrence of fissures and far-reaching defects, sometimes accompanied by adhesions between tendon and navicular bone surface. In radiologically only slightly altered tendons and navicular bones light and scanning electron microscopy often revealed moderate to severe pathological changes, which sometimes could also be seen in clinically healthy horses. The distribution of the lesions indicate that in course of podotrochlosis the initial alterations caused by repeated microtraumata start at the surface of the deep flexor tendon and subsequently spread to the opposite facies flexoria of the navicular bone. An involvement of the cartilage and the synovial layer of the hoof joint in cases with podotrochlosis could only be rarely observed and is to regard as a secondary manifestation.

[The appearance of stress on the movement apparatus in dressage, jumping and versatility horses]. / Belastungserscheinungen am Bewegungsapparat bei Dressur-, Spring- und Vielseitigkeitspferden.

Jumping and military (three days events) horses are exposed, during sports activities, to a particularly high stress especially in the region of the extremities (limbs). The genesis of tendon, joint and bone diseases are traced in accordance to the centers of the load during movement sequence. A special statistics on injuries concerning the German competition horses does not exist yet. Out of the available statistics about the German competition horses it is not obvious that as a result of its use as sports horses a particular high loss occur among these horses.