Black walnut (Juglans nigra) toxicosis: a model for equine laminitis.
Abstract: Twelve light horse geldings developed laminitis within 8 to 12 h of being dosed by nasogastric tube with an aqueous extract of black walnut (Juglans nigra). Four of the 12 horses developed the severe signs of grade 3 laminitis (lame at a walk, refused to lift feet). Laminitis was accompanied by mild depression and limb oedema. There was no evidence of shock or colic. The horses developed neutropenia by 4 h after dosing with the extract, which shifted to a relative neutrophilia by 8 to 12 h. Minimal increases in plasma epinephrine and cortisol concentrations were suggested in severely affected horses. Severe laminitis was characterized by necrosis of dermal tips of dorsal primary epidermal laminae. A proliferative epithelial response in these laminae was distinguished by numerous mitotic figures and clusters of epithelial cells. This evidence suggests that black walnut toxicosis is not only a consistent clinical model, but is also a reliable clinico-pathological and pathological model for study of the pathogenesis and treatment of laminitis.
Publication Date: 1991-04-01 PubMed ID: 2061431DOI: 10.1016/s0021-9975(08)80043-6Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research investigated the effects of black walnut extract on horses, revealing it consistently and reliably induces laminitis, a serious and painful hoof condition, thus providing a clinical and pathological model for studying this disease.
Laminitis Induction
The research centered on inducing laminitis in horses to learn more about the disease. Laminitis is a painful and potentially crippling disease that affects the horse’s foot. The scientists administered extracts of black walnut, a known toxin to horses, by a nasal-gastric tube to provoke the condition.
- Twelve light horse geldings were subjected to this experiment, all of which developed laminitis within 8 to 12 hours after dosing.
- There were varying degrees of severity, with four of the twelve horses demonstrating Grade 3 laminitis, notable for a refusal to lift their feet and lameness even at a walk.
Associated Symptoms
Along with laminitis, the horses exhibited other symptoms that gave a more rounded understanding of the disease.
- Depression and limb edema (swelling generally due to excess fluid) were observed.
- There was no evidence of shock or colic, two conditions often associated with distress in horses.
- Horses had a decreased number of neutrophils, a type of white blood cells, to begin with, but this shifted to a relative increase 8 to 12 hours after dosing.
- Plasma levels of two hormones associated with stress, epinephrine and cortisol, increased slightly in highly affected horses.
Pathological Findings
Post-mortem study helped to shed light on the severe structural damage caused by laminitis.
- The severe laminitis was characterized by tissue death in the tips of certain structures within the hoof (dorsal primary epidermal laminae).
- A proliferative response was found in these tissues characterized by increased cell division and clustering of skin cells.
Conclusion
The study identifies black walnut toxicosis as a consistent and reliable model for inducing laminitis. This could assist in the study of the pathogenesis (development) and treatments for laminitis, helping to improve our understanding of this serious equine health issue.
Cite This Article
APA
Galey FD, Whiteley HE, Goetz TE, Kuenstler AR, Davis CA, Beasley VR.
(1991).
Black walnut (Juglans nigra) toxicosis: a model for equine laminitis.
J Comp Pathol, 104(3), 313-326.
https://doi.org/10.1016/s0021-9975(08)80043-6 Publication
Researcher Affiliations
- Department of Veterinary Biosciences, College of Veterinary Medicine, University of Illinois, Urbana.
MeSH Terms
- Animals
- Blood Chemical Analysis / veterinary
- Disease Models, Animal
- Foot / pathology
- Forelimb / pathology
- Hematologic Tests / veterinary
- Horse Diseases / blood
- Horse Diseases / chemically induced
- Horse Diseases / pathology
- Horses
- Lameness, Animal / etiology
- Nuts / toxicity
- Plant Extracts / toxicity
Citations
This article has been cited 2 times.- Andersen B, Phippen C, Frisvad JC, Emery S, Eustace RA. Fungal and chemical diversity in hay and wrapped haylage for equine feed.. Mycotoxin Res 2020 May;36(2):159-172.
- Coyne MJ, Cousin H, Loftus JP, Johnson PJ, Belknap JK, Gradil CM, Black SJ, Alfandari D. Cloning and expression of ADAM-related metalloproteases in equine laminitis.. Vet Immunol Immunopathol 2009 Jun 15;129(3-4):231-41.
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