Research Article Open Access
Silva et al., J Med Microb Diagn 2018, 7:1
DOI: 10.4172/2161-0703.1000271
Research Article Open Access
Journal of
Medical Microbiology & Diagnosis
ISSN: 2161-0703
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Volume 7 • Issue 1 • 1000271
J Med Microb Diagn, an open access journal
ISSN: 2161-0703
*Corresponding author: Eriques Gonçalves Silva, Governo do Estado
de São Paulo-Secretaria de Estado da Educação, São Paulo, Brazil, Tel:
5511970512752; E-mail: eriques@usp.br
Received January 15, 2018; Accepted January 25, 2018; Published January 29,
2018
Citation: Silva EG, Cavalcanti JN, Viani FC, Silva SMD, Dias ALT (2018)
Tissue Changes in Experimental Cryptococcosis in Immunocompetent and
Immunodefcient Murine Model. J Med Microb Diagn 7: 271. doi:10.4172/2161-
0703.1000271
Copyright: © 2018 Silva EG, et al. This is an open-access article distributed under
the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and
source are credited.
Abstract
Cryptococcosis is a subacute or chronic disease caused through the inhalation of infectious particles from the
opportunistic yeast Cryptococcus neoformans spp. The objective of the present study was to evaluate cryptococcosis
in a murine model Immunocompetent (BALB/c), as well as in a model with combined immunodefciency (SCID)
through histopathological analyzes of pulmonary and cerebral tissues. After intravenous inoculation with 3.0 × 10
5
viable yeast cells the animals were euthanized daily for evaluation. The study period was 15 days. There were no
signifcant changes in lung tissue in immunocompetent murine model (BALB/c). While in brain tissue, it was observed:
congested vessel, evolving when C. neoformans was visualized in the meningeal area, and a large area of ischemia,
which evolved throughout the studied period culminating on the 15
th
day of inoculation with visualization of the yeast
in the meningeal and parenchyma. In SCID model, twenty-four hours after inoculation were observed in the lung
tissue, hemorrhagic areas and a discrete neutrophilic infammatory infltrate, presence of discrete congestion in the
lung, diffuse hemorrhage, edema and intense quantity of yeast were observed on the wall of the capillary at 11 days
after inoculation. In brain tissue discrete area necrosis liquefaction was observed, focal well as the presence of C.
neoformans, interspersed with fragments of necrotic cells was observed. On day 11 after inoculation were large areas
of liquefaction necrosis associated with the formation of cavities in the parenchyma and an intense quantify of the
yeast. Histopathological examination is one of the techniques usually used in the defnitive diagnosis of cryptococcosis.
Tissue Changes in Experimental Cryptococcosis in Immunocompetent and
Immunodeficient Murine Model
Eriques Gonçalves Silva
1
*, Josemar Neves Cavalcanti
2
, Flavio Cesar Viani
3
, Sandra Marilia de Souza Silva
4
and Amanda Latercia Tranches Dias
5
1
Governo do Estado de São Paulo-Secretaria de Estado da Educação, São Paulo, Brazil
2
Faculdade de Americana – (FAM), Americana – São Paulo, Brazil
3
Universidade Cruzeiro do Sul (UNICSUL) – São Paulo, Brazil
4
Universidade Federal do ABC (UNIABC), Santo André, São Paulo, Brazil
5
Universidade Federal de Alfenas (UNIFAL), Alfenas – Minas Gerais, Brazil
Keywords: Chronic disease; Cryptococcosis; C. neoformans; Necrosis
Introduction
Cryptococcosis diseases are caused through the inhalation of
infective particles of the opportunistic C. neoformans, which stay
in the lungs, causing pulmonary cryptococcosis or through the
bloodstream, the yeast can arrives at other organs, mainly in the
central nervous system (CNS), determinant of mortality in mice in
experimental systemic infection. In the brain, C. neoformans can infect
the meninges and through the cerebrospinal fuid (CSF), and the entire
subarachnoid space (meningitis), or present as deep abscess and bulky
(crytococcoma), which is its most common in immunocompetent
patients [1]. Te Crytococcoma is characterized as a solid tumor that
occurs due to a granulomatous reaction composed of macrophages
and lymphocytes, not common in immunosuppressed patients due
to the inability of these patients to initiate an infammatory response
[2]. Most studies in experimental Cryptococcosis have been performed
using murine model studies using these models are well established
in many areas of research, including fungal pathogenesis [3,4]. Te
cerebral cryptococcosis in a murine model accurately reproduces
the main features of the disease in humans and can be used to study
various aspects of the pathophysiology of cryptococcal meningitis [5],
being a valuable tool that contributes to the understanding of how these
infections occur [6]. Te model of systemic cryptococcosis in mice with
severe combined immunodefciency (SCID) is useful for immunological
and therapeutic study of the disease in immunodefcient hosts [7].
Te objective of the study is to evaluate tissue changes in experimental
cryptococcosis in immunocompetent and immunodefcient murine model.
Materials and Methods
Cryptococcus neoformans
Te study was performed using the C. neoformans ATCC 90112
(serotype A). Tis strain was maintained in tubes containing Sabouraud
dextrose agar (Difco Laboratories, Detroit, MI, USA) and glycerol at
-20ºC, in the Laboratory of Pathogenic Yeasts of the Department of
Microbiology, at the Institute of Biomedical Sciences at São Paulo
University, São Paulo, Brazil.
Preparation of the inoculum
Te C. neoformans ATCC 90112 was cultivated in a YPD medium
of 1% yeast extract (Difco), 1% Bacto Peptone (Difco), and 2% dextrose
(Sigma-Aldrich, Milwaukee, WI, USA) for 18 h at 30ºC; the cells were
collected afer centrifugation, washed twice in a phosphate bufer
solution (PBS), and resuspended at the inoculation concentration.
Animal models and experimental cryptococcosis
A total of 55 male BALB/c mice, weighing 24–27 g and 55 murine
models with Severe Combinated Immunodefciency (SCID), with and
a mean weight of 20 g, were used in the study. Were obtained from
the Animal Center, which is responsible for breeding isogenic animals
at the Institute for Energy and Nuclear Research, in São Paulo, Brazil.