Amorimia exotropica is a shrub of the Malpighiacea family that contains sodium monofluoroacetate as the toxic principle, which has a cardiotoxic action in cattle. In Southern Brazil it is the only species of the group of plants that causes "sudden death during exercise". This study has identified and mapped cardiac lesions observed in cattle naturally poisoned by A. exotropica. An outbreak of poisoning by the plant occurred in a beef cattle herd in Rio Grande do Sul, where nine bovine hearts were selected for examination and mapping of eight distinct topographical regions (apex, right and left ventricles, interventricular septum, right and left papillary muscles , right and left atrium). At gross examination, four cattle showed focal and well-defined lesions in the left papillary muscle. This corresponds to areas of coagulation necrosis in different stages of evolution on histology, similar to infarcts. All hearts showed cardiomyocytes necrosis, characterized by shrinkage and hypereosinophilic cytoplasm and cellular fragmentation in all sampled areas. The severity of cellular injury was evaluated by immunohistochemistry anti-troponin C, which showed marked decrease of cytoplasm staining in necrotic cells. The left papillary muscle was the most affected region in cases of poisoning by A. exotropica.
Poisonous plants; Amorimia exotropica; plant poisoning; sudden death association with exercise; cattle; cardiac lesion; immunohistochemistry; troponin
