Timing of Expression of Inflammatory Mediators in Skeletal Muscles from Mice Acutely Infected with the RA Strain of Trypanosoma cruzi

Objective: Chagas' disease is caused by persistent Trypanosoma cruzi infection in muscle cells that ultimately results in chronic inflammation and tissue destruction. The goal of this study was to determine the expression of different chemokines and their receptors, as well as proinflammatory cytokines and inducible nitric oxide synthase, in muscles from mice acutely infected with T. cruzi. Methods: Histological, semiquantitative reverse transcriptase polymerase chain reaction and immunohistochemical studies were performed on skeletal muscle and myocardium of BALB/c mice infected with T. cruzi, RA strain. Results: Early induction of muscular mRNA expression for CCL5/CCR5 and CXCL9/CXCR3, as well as for iNOS, IFN-gamma, TNF-alpha and MIF, was demonstrated accompanied by progressive increases in parasitism and leukocyte recruitment. Protein overexpression for MIF and CCL5/CCR5 was also verified in the infected muscles. Conclusions: In muscles from acutely T. cruzi RA-infected mice, upregulated gene expression of proinflammatory chemokines, chemokine receptors, cytokines and iNOS is associated with the severity of parasite burden and myopathic alterations. Compared to the heart, striated muscles displayed differential timing of expression of several inflammatory mediators throughout acute infection. Our findings suggest that enhanced early production of these factors could contribute to T. cruzi-dependent inflammatory damage to skeletal muscles. Copyright (C) 2009 S. Karger AG, Basel