Spontaneous and experimental poisoning with the swainsonine-containing and calystegine-containing plant Ipomoea carnea subsp fistulosa is described. Three of 8 goats presenting with emaciation, weakness, symmetrical ataxia, posterior paresis, proprioceptive deficits, abnormal posture, abnormal postural reaction, and muscle hypertonia were necropsied. I fistulosa was suspected to be the cause of the neurologic disease in all cases. An experiment was conducted to confirm the diagnosis using 12 goats and diets containing 3 different concentrations of the plant. All goats fed I fistulosa developed neurological signs that were similar to those observed in the spontaneous intoxication. Muscle atrophy and pallor were the only macroscopic changes observed in spontaneous and in experimental intoxication. Histological lesions of spontaneous and experimental animals were similar. The most prominent lesion was cytoplasmic vacuolation in neurons of the central and the autonomous nervous system, pancreatic acinar cells, hepatocytes, Kupffer cells, follicular epithelial cells of the thyroid gland, and macrophages of the lymphatic tissues. Neuronal necrosis, axonal spheroids formation, and astrogliosis were additionally observed in the brain. Ultrastructurally, the cytoplasmic vacuoles consisted of distended lysosomes surrounded by a single-layered membrane. Nonreduced end-rests or sequence of α-Man, α-Glc, β(1-4)-GlcNAc, and NeuNAc on lysosomal membrane were revealed by lectin histochemistry. Samples of plants used in the experimental trial contained swainsonine and calystegine and their intermediary derivate. We conclude that I fistulosa induces a glycoprotein storage disease primarily based on the inhibition of the lysosomal α-mannosidase by the alkaloid swainsonine.
Bibliographical noteFunding Information:
This work was supported by Projeto Saude Animal Empresa Brasileira de Pesquisa Agropecuaria/Universidade Federal Rural de Rio de Janeiro and Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro, Brazil; Deutschen Akademischen Austauschdienst DAAD and Institut für Veterinär-Pathologie der Justus-Liebig-Giessen Universität, Germany. We thank Dr. R. J. Molyneux for the toxicological analysis. We thank Dr. Severe Barros for E&M-technical advice, Dr. A. Wünschmann and Dr. R. Gunther for the review of this manuscript. We also thank Mrs. S. Krauskopf, Mrs. A. Artelt, Mrs. U. Zeller, Mr. J-L. Bastos, Mr. J-C Beata da Cruz, and Mr. W. Fonseca for technical assistance.
Copyright 2008 Elsevier B.V., All rights reserved.
- Ipomoea carnea subsp fistulosa
- Lectin histochemistry
- Lysosomal storage disease
- Plant poisoning