Avaliação das lesões cardíacas e encefálicas induzidas pelas intoxicações por Ateleia glazioviana e Tetrapterys multiglandulosa em ovinos

Abstract

The reversibility of the cardiac and brain lesions was studied in sheep intoxicated experimentally by Ateleia glazioviana and Tetrapterys multiglandulosa in 3 groups of 4 sheep each. Other two sheep were used as control. Four sheep received green A.glazioviana collected during autumn in the dose of 10 g/kg body weight during six days. A second group received A.glazioviana collected in spring also in a daily dose of 10g/kg during 8 days. Four sheep received dry and ground T. multiglandulosa at 10g/kg daily for 11 days. In the three groups the administration was suspended when all the animals in each group showed evident nervous signs. Clinical signs were depression and incoordination, and all animals recovered in 3-4 days after the end of the administration. One animal of each group was euthanized at the end of ingestion, and the others in different periods, varying between 5 and 150 days, after the end of the administration. Status spongiosus, mainly in the subcortical cerebral white matter, was observed in all animals. These lesions were less severe in the animals with longer periods between the end of administration and euthanasia. Macroscopic lesions were not observed in the heart of any sheep. Histologic lesions of the heart, characterized by multiple foci of cardiomiocites with cytoplasmatic eosinophilia and vacuolization, increased nuclear size, necrosis of some fibers, moderate fibrosis, and scant number of macrophages were observed in sheep that ingested A. glazioviana collected in the autumn and in sheep ingesting T. multiglandulosa, but not in sheep ingesting A. glazioviana collected in the spring. The lesions in the group ingesting A. glazioviana collected in autumn were more evident in sheep with longer period between the end of administration and euthanasia. In sheep intoxicated by T. multiglandulosa, cardiac histologic lesions were similar, but they do not progress after the end of the administration. These results suggest that doses relatively high of A. glaziovina and T. multiglandulosa cause reversible nervous signs, but not cardiac insufficiency. The animals showed histologic cardiac lesions, but these lesions do not progress to cause cardiac insufficiency.