Toxoplasma gondii infection in the peritoneal macrophages of rats treated with glucocorticoids

Wang, T; Gao, J; Yi, SQ; Geng, GQ; Gao, XJ; Shen, JL; Lu, FL; Wen, YZ; Hide, G; Lun, ZR

Abstract

It is well known that toxoplasmosis can be life
threatening to immunocompromised individuals such as
AIDS and organ transplantation patients. Glucocorticoids
(GCs) are widely used in the clinic for the treatment of
autoimmune diseases and organ transplantation resulting in
acute toxoplasmosis in these patients. However, the interaction
and mechanism between the development of acute toxoplasmosis
and GC therapy are still unknown. The aims of this
study were to investigate the infection of Toxoplasma gondii
in the peritoneal macrophages of rats treated with glucocorticoids.
Our results showed that the growth rate of T. gondii RH
strain was significantly increased in the peritoneal macrophages
of rats treated with glucocorticoids in vivo. For instance,
242 (±16) tachyzoites were found in 100 macrophages
from the rats treated with methylprednisolone (MP), while
only 16 (±4) tachyzoites were counted in the macrophages
from the non-treated control rats 24 h after infection (P <
0.01). We also demonstrated that a significant inhibition of
nitric oxide (NO) production was detected in the macrophages
collected from the rats post-treated with GCs with 12.90 μM
(±0.99 μM) of nitrite production fromthe rats treatedwithMP,
while 30.85 μM (±1.62 μM) was found in the non-treated
control rats 36 h after incubation (P <0.01). Furthermore,
glucocorticoids could significantly inhibit the expression of
inducible nitric oxide synthase mRNA and its protein in the rat
peritoneal macrophages. Our results strongly indicate that the
decrease of NO in the rat peritoneal macrophages is closely
linked to the cause of acute toxoplasmosis in the host. Additionally,
there was a significant increase in the number of cysts
produced by the naturally cyst forming, T. gondii Prugniaud
strain with an average of 2,795 (±422) cysts of the parasite
being detected in the brains of the rats treated with dexamethasone,
while only 1,356 (±490) cysts were found in the nontreated
control animals (P <0.01). As rats and humans are
both naturally resistant to T. gondii infection, these novel data
could lead to a better understanding of the development of
acute toxoplasmosis during glucocorticoid therapy in humans.

• Journal Article Type: Article
• Acceptance Date: Oct 18, 2013
• Online Publication Date: Nov 19, 2013
• Publication Date: Jan 1, 2014
• Deposit Date: Jan 21, 2015
• Publicly Available Date: Apr 5, 2016
• Journal: Parasitology Research
• Print ISSN: 0932-0113
• Electronic ISSN: 1432-1955
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 113
• Issue: 1
• Pages: 351-358
• DOI: https://doi.org/10.1007/s00436-013-3661-3
• Publisher URL: http://dx.doi.org/10.1007/s00436-013-3661-3
• Related Public URLs: http://link.springer.com/article/10.1007%2Fs00436-013-3661-3
• Additional Information: Access Information : The final publication is available at Springer via Official URL; Funders : National Basic Research Program of China; Grant Number: 973 program; no.2010CB530000