title: Microcirculation abnormalities provoked by Loxosceles spiders' envenomation.
abstract: Loxoscelism is caused by envenomation by spiders from Loxosceles genus. Clinical symptoms only appear a few hours after envenomation and can evolve in local reactions, such as dermonecrosis, and systemic reactions, including intravascular haemolysis, intravascular coagulation and renal failure. Considering that alterations in the microcirculatory network are involved in the pathogenesis of different diseases, including the inflammatory process, the aim of this study was to investigate the action of venoms of males and females of Loxosceles intermedia and Loxosceles laeta on the microcirculatory network and examine the systemic production of inflammatory mediators in a murine model of loxoscelism. We observed that during systemic envenomation, the alterations in the microcirculation include increase in the number of rolling cells, which was more intense in animals injected with female Loxosceles spider venoms. This positively correlated with increase in TNF-α and NO serum levels, induction of which was higher by female venoms when compared with male venoms. The increase of leukocytes rolling was not accompanied by increase of cell adhesion. The absence of leukocyte extravasation may explain why in mice, in contrast to humans, no cutaneous loxoscelism occurs. Thus, targeting the neutrophil adhesion and extravasation in Loxosceles envenomed patients may prevent cutaneous pathology.
authors.affiliation: Immunochemistry Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Kátia
authors.initials: K
authors.lastname: Cristina de Oliveira-Lima
authors.affiliation: Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo, Brazil.
authors.forename: Sandra Helena P
authors.initials: SH
authors.lastname: Farsky
authors.affiliation: Immunochemistry Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Priscila Hess
authors.initials: PH
authors.lastname: Lopes
authors.affiliation: Immunochemistry Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Rute Maria Gonçalves
authors.initials: RM
authors.lastname: de Andrade
authors.affiliation: Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff University, Cardiff, UK.
authors.forename: Carmen W
authors.initials: CW
authors.lastname: van den Berg
authors.affiliation: Immunochemistry Laboratory, Butantan Institute, São Paulo, Brazil. Electronic address: denise.tambourgi@butantan.gov.br.
authors.forename: Denise V
authors.initials: DV
authors.lastname: Tambourgi
mesh_terms: D000818:Animals; D005260:Female; D007962:Leukocytes / Q000187:drug effects / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008833:Microcirculation / Q000187:drug effects*; D009504:Neutrophils / Q000187:drug effects; D009569:Nitric Oxide / Q000097:blood; D001098:Spider Bites / Q000503:physiopathology*; D013111:Spider Venoms / Q000633:toxicity*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D013111:Spider Venoms; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide
keywords: Inter- and intra-specific variations; Loxosceles spider venom; Microcirculation