Alterações clínicas, laboratoriais e histopatológicas (locais e sistêmicas) causadas pelo veneno da aranha Loxosceles intermedia em cobaias (Cavia porcellus)

Abstract

Spiders of the genus Loxosceles, popularly known as brown spiders, are responsible for most reported cases of accidents caused by arachnids. Its venom has a complex protein composition, with phospholipases D being its main toxin. The clinical picture ranges from the evolution of dermonecrotic lesions to systemic manifestations, which are little studied. Given this context, the present study aimed to evaluate the systemic and local changes caused after intradermal administration of different concentrations of Loxosceles intermedia venom in guinea pigs (Cavia porcellus) for 72 hours. Eighteen adult male animals were used, with 16 animals receiving doses ranging from 11,627 to 350 μg of L. intermedia venom and two receiving a placebo, control animals. The guinea pigs were clinically evaluated, after envenomation, by means of complete blood count and biochemical blood profile, urine tests (urinalysis and electrophoretic profile) and electrocardiogram. After 72 hours of envenoming (death/euthanasia), necropsy was performed and samples were collected for histopathological analysis. The guinea pigs showed symptoms of viscerocutaneous loxoscelism, with the appearance of discrete dermonecrotic lesions, as well as hematological alterations (anemia, hemolysis, neutrophilia and thrombocytopenia); renal (azotemia, increased serum levels of SDMA, hyperphosphatemia and histopathological alterations) and urinary disorders (proteinuria, with the presence of low and high molecular weight proteins, increased urinary urea:creatinine ratio and increased levels of urinary GGT); cardiovascular alterations (electrocardiographic changes, increased serum levels of CK and its MB fraction, as well as of Troponin I and LDH); and histopathological lesions in the liver, such as necrosis and hepatitis, and in the central nervous system (encephalitis). Thus, it was possible to conclude that L. intermedia venom causes severe systemic clinical symptoms in guinea pigs, making this animal a good experimental model, especially for systemic loxoscelism.