Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/11390
Title: Apoptosis, mast cell degranulation and collagen breakdown in the pathogenesis of loxoscelism in subcutaneously implanted sponges
Authors: Pereira, Núbia Braga
Campos, Paula Peixoto
Parreiras, Patrícia Martins
Garcia, Hélio Chiarini
Socarrás, Teresa Oviedo
Kalapothakis, Evanguedes
Andrade, Silvia Passos
Moro, Luciana
Affilliation: Universidade Federal de Minas Gerais. Departamento de Patologia Geral. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Departamento de Patologia Geral. Belo Horizonte, MG, Brazil
Fundação Oswaldo Cruz. Centro de Pesquisas René Rachou. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Departamento de Morfologia. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Departamento de Patologia Geral. Belo Horizonte, MG, Brazil/Universidad de Córdoba. Departamento de Ciencias Pecuárias. Colombia/Universidad de Córdoba. Facultad de Medicina Veterinaria y Zootecnia. Colombia.
Universidade Federal de Minas Gerais. Departamento de Biologia Geral. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Departamento de Fisiologia e Biofísica. Belo Horizonte, MG, Brazil
Universidade Federal de Minas Gerais. Departamento de Patologia Geral. Belo Horizonte, MG, Brazil
Abstract: Envenomation by the Loxosceles spider causes loxoscelism, a pattern of signs and symptoms that primarily manifests in the dermonecrotic form. Our studies have shown that a mouse subcutaneous sponge implantation model may be useful in evaluating the effects of Loxosceles similis venom. This model provides an ideal microenvironment in which to study loxoscelism; however, it is still important to evaluate its pathogenesis and to observe the effects of L. similis venom for longer time periods than those in previous studies of this model. The aims of this study are: (1) to histologically characterize the effects of L. similis crude venom in a subcutaneous sponge implant; (2) to quantify the mast cells present in the implant and to measure their degranulation activity; (3) to quantify collagen subtypes I and III; and (4) to verify, quantify, and evaluate the effects of apoptosis in the implant on the pathogenesis of loxoscelism at 1 h, 4 h, and 24 h after injecting the venom. Thirty Swiss mice (6-8 weeks old, male) were subcutaneously implanted with polyester-polyurethane sponge discs. Fourteen days post-implantation, the animals were divided into six groups (5 animals per group): three control groups (C1h, C4h, and C24h), in which the mice received 30 μl injections of intra-implant saline, and three treated groups (T1h, T4h, and T24h), in which the mice received 30 μl (0.5 μg) injections of L. similis crude venom at 1 h, 4 h, and 24 h intervals. After each time interval, the animals were euthanized, and the implants were harvested and processed for light and electron microscopic analyses. The following results were observed in the implants harvested from the treated groups: acute inflammation with marked edema, thrombus, and vasculitis, as well as increased levels of mast cells and mast cell degranulation, and apoptosis in giant cells. Furthermore, degradation of collagen types I and III was observed. An analysis of the ultrastructure revealed apoptosis in various cell types. The present results suggest that apoptosis in some cell types associated with an increase in mast cell degranulation and the degradation of collagen fibers are important in the pathogenesis of loxoscelism therefore may explain the difficulty in repairing the ulcer is commonly observed in severe cases of loxoscelism cutaneous in humans.
Keywords: Loxosceles
Loxoscelism
Sponge implants
Apoptosis
Issue Date: 2014
Publisher: Pergamon Press
Citation: PEREIRA, Núbia Braga et al. Apoptosis, mast cell degranulation and collagen breakdown in the pathogenesis of loxoscelism in subcutaneously implanted sponges.Toxicon., vol. 84, p. 7-18, 2014
DOI: 10.1016/j.toxicon.2014.03.003
ISSN: 0041-0101
Copyright: restricted access
Appears in Collections:MG - IRR - Artigos de Periódicos

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