Lamellar cell death and proliferation are associated with restricted ambulation and preferential weight bearing in a model relevant to supporting-limb laminitis.
Julie B Engiles, Darko Stefanovski, Andrew van Eps
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引用次数: 0
Abstract
Objective: To examine the effects of prolonged preferential weight bearing (PWB) and reduced ambulation (RA) on hoof lamellae using a nonpainful in vivo experimental model.
Methods: 12 healthy Standardbred horses were housed in stocks continuously for 92 hours. A platform shoe was placed on 1 forelimb in the PWB group (n = 6) to increase the load on the supporting limb (SL) by approximately 10% bodyweight, whereas the RA group (n = 6) had normal weight bearing. Archived healthy horse (n = 8) samples were used as controls. Histomorphometry and histochemistry (terminal deoxynucleotidyl transferase dUTP nick-end labeling [TUNEL], caspase-3, and targeting protein for Xenopus kinesin-like protein [TPX-2]) results were analyzed using mixed-effects linear regression.
Results: Lesions in multiple limbs from the PWB and RA groups included secondary epidermal lamellae elongation, cell death (mostly TUNEL-positive, caspase-3-negative parabasal keratinocytes), and basal cell proliferation (TPX-2 positive). Lesions were most severe in the PWB group SL, with significant increases (vs control) in mean (95% CI) primary epidermal lamellar (PEL) length (3.7 [95% CI, 3.5 to 3.8] mm vs 3.2 [95% CI, 2.9 to 3.4] mm; P < .001), secondary epidermal lamellae length (281 [95% CI, 235 to 327] µm vs 185 [95% CI, 155 to 215] µm; P < .001), TUNEL count (45 [95% CI, 30 to 60] vs 4 [95% CI, 2 to 5] positive cells/PEL; P < .001), and TPX-2 count (116 [95% CI, 46 to 186] vs 5 [95% CI, 3 to 6] positive cells/PEL; P < .002). Both TUNEL- and TPX-2-positive cell counts were increased in the RA group forelimbs versus control (P < .05).
Conclusions: Restriction of normal ambulation, even in the absence of increased weight bearing, caused lamellar parabasal keratinocyte death and structural derangement of lamellae.
Clinical relevance: Promoting ambulation, not just limb load relief, may be a critical strategy for preventing SL laminitis.
期刊介绍：
The American Journal of Veterinary Research supports the collaborative exchange of information between researchers and clinicians by publishing novel research findings that bridge the gulf between basic research and clinical practice or that help to translate laboratory research and preclinical studies to the development of clinical trials and clinical practice. The journal welcomes submission of high-quality original studies and review articles in a wide range of scientific fields, including anatomy, anesthesiology, animal welfare, behavior, epidemiology, genetics, heredity, infectious disease, molecular biology, oncology, pharmacology, pathogenic mechanisms, physiology, surgery, theriogenology, toxicology, and vaccinology. Species of interest include production animals, companion animals, equids, exotic animals, birds, reptiles, and wild and marine animals. Reports of laboratory animal studies and studies involving the use of animals as experimental models of human diseases are considered only when the study results are of demonstrable benefit to the species used in the research or to another species of veterinary interest. Other fields of interest or animals species are not necessarily excluded from consideration, but such reports must focus on novel research findings. Submitted papers must make an original and substantial contribution to the veterinary medicine knowledge base; preliminary studies are not appropriate.
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