Trypanosoma cruzi infection in rats induced early lesion of the heart noradrenergic nerve terminals by a complement-independent mechanism.
The acute phase of the experimental Chagas' disease in rats induces extensive lesion of the heart sympathetic nerve terminals. Because of evidence indicating the involvement of immune reactions in neuron destruction provoked by Chagas' disease, we tested the effects of depleting the complement system by cobra venom factor upon the sympathetic denervation. The serum hemolytic activity against sensitized sheep erythrocytes ensured the efficacy of the anticomplementary treatment. Glyoxylic acid-induced histofluorescence and electron-microscopic methods allowed the study of the heart noradrenergic nerves. T. cruzi infection caused marked rarefaction of fluorescent nerve terminals at day 10 of infection and the ultrastructural study guaranteed that this rarefaction involved lesion of noradrenergic terminals. The complement depletion failed to prevent this early heart noradrenergic denervation, excluding the participation of complement-mediated lysis as a main mechanism.
Machado
C R
CR
Department of Morphology, Federal University of Minas Gerais, Belo Horizonte, Brazil.
de Oliveira
D A
DA
Magalhaes
M J
MJ
Carvalho
E M
EM
Ramalho-Pinto
F J
FJ
D000818:Animals; D014355:Chagas Disease / Q000473:pathology*; D003165:Complement System Proteins / Q000032:analysis / Q000502:physiology*; D004546:Elapid Venoms / Q000494:pharmacology; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D005455:Fluorescent Antibody Technique; D006038:Glyoxylates / Q000378:metabolism; D006321:Heart / Q000294:innervation*; D006461:Hemolysis; D006651:Histocytochemistry; D009206:Myocardium / Q000473:pathology; D009411:Nerve Endings / Q000378:metabolism / Q000502:physiology / Q000648:ultrastructure*; D009638:Norepinephrine / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D012756:Sheep / Q000276:immunology; D014349:Trypanosoma cruzi
D004546:Elapid Venoms; D006038:Glyoxylates; C016310:cobra venom factor; D003165:Complement System Proteins; C031150:glyoxylic acid; D009638:Norepinephrine