Article
In vivo imaging of mice infected with bioluminescent Trypanosoma cruzi unveils novel sites of infection
Registro en:
HENRIQUES, Cristina; et al. In vivo imaging of mice infected with bioluminescent Trypanosoma cruzi unveils novel sites of infection. Parasites & Vectors, v.7:89, 15p, 2014.
1756-3305
10.1186/1756-3305-7-89
Autor
Henriques, Cristina
Pons, Andréa Henriques
Batista, Marcelo Meuser
Ribeiro, Aline Salgado
Souza, Wanderley de
Resumen
Background: The development of techniques that allow the imaging of animals infected with parasites expressing
luciferase opens up new possibilities for following the fate of parasites in infected mammals.
Methods: D-luciferin potassium salt stock solution was prepared in phosphate-buffered saline (PBS) at 15 mg/ml.
To produce bioluminescence, infected and control mice received an intraperitoneal injection of luciferin stock solution
(150 mg/kg). All mice were immediately anesthetized with 2% isofluorane, and after 10 minutes were imaged.
Ex vivo evaluation of infected tissues and organs was evaluated in a 24-well plate in 150 μg/ml D-luciferin diluted
in PBS. Images were captured using the IVIS Lumina image system (Xenogen). Dissected organs were also evaluated by
microscopy of hematoxylin-eosin stained sections.
Results: Here we describe the results obtained using a genetically modified Dm28c strain of T. cruzi expressing the
firefly luciferase to keep track of infection by bioluminescence imaging. Progression of infection was observed in vivo in
BALB/c mice at various intervals after infection with transgenic Dm28c-luc. The bioluminescent signal was immediately
observed at the site of T. cruzi inoculation, and one day post infection (dpi) it was disseminated in the peritoneal cavity.
A similar pattern in the cavity was observed on 7 dpi, but the bioluminescence was more intense in the terminal region
of the large intestine, rectum, and gonads. On 14 and 21 dpi, bioluminescent parasites were also observed in the heart,
snout, paws, hind limbs, and forelimbs. From 28 dpi to 180 dpi in chronically infected mice, bioluminescence declined
in regions of the body but was concentrated in the gonad region. Ex vivo evaluation of dissected organs and tissues
by bioluminescent imaging confirmed the in vivo bioluminescent foci. Histopathological analysis of dissected organs
demonstrated parasite nests at the rectum and snout, in muscle fibers of mice infected with Dm28c-WT and with
Dm28c-luc, corroborating the bioluminescent imaging.
Conclusion: Bioluminescence imaging is accurate for tracking parasites in vivo, and this methodology is important to
gain a better understanding of the infection, tissue inflammation, and parasite biology regarding host cell interaction,
proliferation, and parasite clearance to subpatent levels.