Brain, liver and kidney lesions associated with Loxosceles intermedia envenomation in guinea pigs

The venom of Loxosceles spiders is characterized by a complex protein composition, which underlies the clinical condition known as loxoscelism. This syndrome is characterized mainly by gravitational spreading dermonecrotic lesions, but also, in rare cases, it can involve severe systemic complications, such as renal failure and hematological disorders. Although the pathophysiological mechanism of cutaneous loxoscelism is widely investigated, the neurological manifestations associated with the venom are rare and poorly researched. The present study aimed to investigate the histopathological alterations in guinea pigs' (Cavia porcellus) liver, kidney, and central nervous system (CNS) inoculated with Loxosceles intermedia venom. Sixteen guinea pigs were challenged with venom doses ranging from 11.627 to 350 μg/animal intradermally in the intrascapular region, while two additional animals were used as controls, receiving only 0.9 % saline solution in the same application region. Microscopic evaluation of hepatic and renal tissues demonstrated hepatic necrosis and acute renal tubular necrosis, respectively. In the CNS, lesions compatible with lymphoplasmacytic and histiocytic encephalitis, moderate focal gliosis, and neutrophilic margination in certain regions of the brain were identified. These neurological findings in guinea pigs exposed to L. intermedia venom are unprecedented, providing new evidence of CNS susceptibility to Loxosceles venom. Keywords: brown spider; loxoscelic venom; central nervous system; encephalitis; loxoscelism. Keywords: brown spider, loxoscelic venom, central nervous system, encephalitis, loxoscelism.