Clinical TechniqueEvaluation of the Integrity of Horse Hoof Dermal and Epidermal Tissues Collected by Dorsal Transmural Access
Introduction
Even after a thousand years of domestication, the phrase “no foot, no horse” demonstrates the importance of many regulatory mechanisms that control the growth and function of the hoof [1].
The morphological and functional features of a horse's hoof contribute to its speed and versatility yet also leads to numerous disorders, among which laminitis is the most prevalent [2]. This disease has been the motivation for several studies that sought to clarify its pathogenesis. Much progress has been made on this front, and it is recognized that, regardless of the causal factor, the disease has a temporal aspect. However, the difficulty in accessing the dermal and epidermal tissues as the disease progresses has been one of the major impediments to evaluating hoof diseases in research protocols.
Relatively few studies have described biopsying the hoof via dorsal transmural access. The few attempts to perform a hoof biopsy were made at the junction between the sole and the caudal portion of the hoof in both cattle [3], [4] and horses [5], [6], [7], [8].
Studies using a single laminar biopsy have been performed after inducing laminitis with carbohydrate overload [5] and in spontaneous laminitis [8]. Moreover, serial hoof biopsies were performed after laminitis was induced by oligofructose administration [6] and in conscious, healthy horses [7]. The authors proposed two different techniques to serially obtain laminar tissue from a hole made with a rotary drill in the dorsal aspect of the forelimb hoof. One author [7] described cutting the laminae with a disposable biopsy punch and detached it from the distal phalanx with an ophthalmic scalpel. The others [6] obtained their samples by using a scalpel blade to cut and curved-tip blade to detach the tissue.
Considering the previous techniques, the purpose of this study was to obtain dermal and epidermal tissues collected through a novel technique using dorsal transmural access. Moreover, to determine the effectiveness of our technique, we evaluated the quality of the samples by optical and electron microscopies.
Section snippets
Materials and Methods
Eight healthy adult mixed-breed horses (four males and four females, with a mean age of 14 ± 1 years and a mean body mass of 328 ± 13 kg) were used in this study. The horses were previously evaluated both clinically and radiographically to ensure that they had no existing foot pathology.
Food (but not water) was withheld for 12 hours before the surgical procedure. Procaine penicillin G (22,000 U/kg) was injected intramuscularly preoperatively. The surgeries were performed with horses restrained
Results
None of the animals showed an increase in the heart or respiratory rates or became lame during the protocol. No signs of local infection were detected. The radiographic evaluations verified the integrity of the phalangeal surface and also the regularity and good alignment of the phalanx with the hoof wall.
The laminar sample was a cuboid that measured approximately 5 mm at the base and was 7 mm in height.
After rinsing with saline and fixing in buffered formalin solution, the primary epidermal
Discussion
With regard to performing a hoof biopsy to assess laminar tissue, there are only six reports of this procedure, of which five were in horses [6], [7], [9], [10], [11] and one was in cattle [3]. The first step to obtain a laminar tissue sample was to drill a cone-shaped hole in the hoof wall, from which the external extract and the rigid part of the stratum medium were removed using a grinding stone attached to a rotary drill. This method of opening a hole in the hoof wall to access the laminar
Conclusions
Based on the results of our study, we conclude that our method of collecting laminar tissue by biopsy in healthy horses enables the serial collection of material for histological analysis and electron microscopy. More importantly, both analyses showed that the samples did not sustain structural damage. Our procedure resulted in no signs of lameness, which makes its use feasible in healthy horses during the experimental protocols. Therefore, this modified biopsy technique can be considered an
Acknowledgments
The study received ethical approval by Comissão de Ética e Bem Estar Animal (CEBEA)—FCAV/UNESP, Jaboticabal, São Paulo (Protocol no 027914/09). The authors acknowledge Cordenação de Aperfeiçoamento de pessoal de nível Superior (CAPES) for financial assistance.
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