Thymic Atrophy in Cattle Experimentally Intoxicated with Solanum glaucophyllum (Sg)

FONTANA PA; PORTIANSKY EL; GIMENO EJ; COSTA EF; BARBEITO CG

Belo Horizonte, Brasil

Congreso; XII ENAPAVE (Encontro Nacional de Patologia Veterinaria); 2005

Sociedad de Patologia de Brasil

Bovine enzootic calcinosis is a disease produced by the chronic ingestion of Sg. The active principle, 1,25-dihydroxyvitamin D3 or calcitriol, has hypercalcemic but also immunomodulator properties. The aim of this study was to determine the effect of Sg-intoxication on the thymus of the Sg-intoxicated heifers. The animals received 2 weekly doses of Sg during 15, 30 or 60 days. A recovered group was intoxicated during 15 days but sacrificed to the 60 days post-intoxication (pi). The controls were sacrificed to the 0 and 60 days pi. The thymus were formalin-fixed paraffin-embedded and stained with H/E and PAS. Lectinhistochemistry was conducted with the following biotinylated lectins: WGA, RCA-1, DBA, PNA, UEA-1, Con-A, SBA. Immunohistochemistry against pan-cytokeratin was also done. The thymic parenchyma showed atrophy and substitution by fatty tissue proportionally to the advance of the intoxication. It decreased mainly at the cortical region, and the cortico - medullary limits already disappeared from the day 30 pi. The organs of the recovered group were similar to that of the controls. PAS stain showed an increase of conjunctive tissue and diffuse distribution of the PAS + epithelial cells, in the intoxicated heifers. The distribution pattern was different in recovered and control animals, in which these cells were located at the medullar area. DBA demonstratyed the epithelial cells, in a similar way to the PAS and cytoqueratin immunostaining. PNA labeled cortical thymocytes and confirmed the progressive decrease of the cortex in the intoxicated animals. Our results confirm the thymic involution in the heifers intoxicated with Sg.