TOXICITY OF RABBITS DUE TO SOLANUM GLAUCOPHYLLUM: AN EXPERIMENTAL MODEL FOR ENZOOTIC CALCINOSIS

FONTANA PA, ZANUZZI CN, GOMAR MS, BARBEITO CG, PORTIANSKY EL AND GIMENO EJ

Tucson, Arizona

Congreso; 57 th Annual Meeting of the American College of Veterinary Pathologists (ACVP); 2006

American Society for Veterinary Clinical Pathology

Enzootic calcinosis is a chronic plant intoxication of cattle characterized by calcification of soft tissues and loss of body weight. In Argentina it is caused by the ingestion of leaves of Solanum glaucophyllum containing high levels of 1,25-dihydroxyvitamin D3. Vitamin D3 influences mineral homeostasis, cellular differentiation and proliferation of diverse organs and the immune system. Previous works performed in our laboratory have shown the effects of hypervitaminosis D on the skin, aorta, lungs and lymphoid organs of the intoxicated cattle. Our goal was to reproduce the ruminant illness in a rabbit model and to further investigate the pathogenesis of the intoxication. Several doses (125, 300, 500 mg/kg/day) of the powdered plant and intoxication times (4, 8 or 20 days) were tested. Aorta, skin, lung, thymus and small intestine of 3 month-old New Zealand male rabbits were studied. Diverse histochemical, lectin-histochemical, immnunohistochemical and morphometric analyses were done. Atrophy of the epidermis, hair follicles, sebaceous and sweat glands, and a reduction in the epidermal proliferation rate was observed. Specific bone proteins, such as osteocalcin, osteopontin and osteonectin, were immunodetected in activated fibroblasts, modified smooth muscle cells and extracellular matrix in the aortas and lungs of the intoxicated rabbits. Paneth cells in the intestine increased the morphometric characteristics of area, axes, perimeter and roundness with intoxication time and dose. Cortical atrophy of the thymus observed in heifers was not reproduced in rabbits. Even though no pathological changes were observed in the thymus the lesions observed in the remaining analyzed organs resembled those described previously in cattle. Therefore, rabbits can be considered an appropriate model for studying the pathogenesis of a enzootic calcinosis, a disease that causes significant economic loss.