immunology of infectious and parasitic diseases - XXXVII Congress ...

THE INVOLVEMENT OF HEME OXYGENASE-1 (HO-1) IN THE CONTROL
OF Toxoplasma gondii REPLICATION IN C57BL/6 MICE
ESTER CRISTINA BORGES ARAUJO 1 ; BELLISA DE FREITAS BARBOSA 2 ;
PAULO VICTOR CZARNEWSKI BARENCO 1 ; LUCIANA ALVES DE SOUSA 1 ;
LOYANE BERTAGNOLLI COUTINHO 1 ; ELOISA AMÁLIA VIEIRA FERRO 2 ;
DEISE APARECIDA OLIVEIRA SILVA 3 ; CRISTIANE MARIA MILANEZI 4 ;
GIULIANO BONFÁ 4 ; JOÃO SANTANA SILVA 4 ; JAIR PEREIRA DA CUNHA-
JÚNIOR 3 ; NEIDE MARIA SILVA 1
1 Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal
University of Uberlândia,
2 Laboratory of Histology and Embryology, Institute of Biomedical Sciences,
Federal University of Uberlândia,
3
Laboratory of Immunoparasitology, Institute of Biomedical Sciences, Federal
University of Uberlândia,
4
Department of Biochemistry and Immunology, School of Medicine of Ribeirão
Preto, University of São Paulo.
Introduction: Toxoplasma gondii is an apicomplexan parasite characterized to
induce type 1 immune response in infected hosts and the disease occurs mainly
in immunocompromised individuals. Heme oxygenase-1 (HO-1) is the enzyme
that catabolizes free heme that induces an intense inflammatory response.
Furthermore, the expression of HO-1 is induced by different stimuli, triggering
an anti-inflammatory response during biological stress. Additionally, it was
previously verified that HO-1 are able to induce the indoleamine 2,3dioxygenase
(IDO), an enzyme known to be involved in the parasite control.
Methods and Results: To verify the role of HO-1 during in vivo infection,
BALB/c and C57BL/6 mice were infected with ME49 strain of T. gondii and
treated during 12 days with zinc protoporphyrin IX (ZnPPIX) or hemin, which
inhibit or induce HO-1 expression, respectively. The results showed that
C57BL6 and BALB/c mice treated with ZnPPIX showed higher tissue parasitism
in the lung (BALB/c: 3.71 ± 2.36; C57BL/6: 35.00 ± 19.8), whereas treatment
with hemin decreased the replication of the parasite in this organ (BALB/c: 0.35
± 0.43; C57BL/6: 1.82 ± 2.37) and in the small intestine of C57BL/6 infected
mice (1.25 ± 0.93). It was observed that T. gondii infection induced high levels
of HO-1 mRNA in the lung of infected mice. Furthermore, C57BL/6 mice treated