Related Experiment Videos
[Experimental Encephalitozoon cuniculi infection in dexamethasone-immunosuppressed mice]
Maria Anete Lallo1, Maurício José dos Santos, Eduardo Fernandes Bondan
1Curso de Medicina Veterináia, Universidade Paulista, São Paulo, SP, Brasil. bondan@uol.com.br
Objective:
Microsporidian Encephalitozoon cuniculi has been recognized as an opportunistic pathogen in immunosuppressed individuals, such as AIDS patients. The objective of the study was to develop pharmacologically immunosuppressed animals as a model of the natural occurring E. cuniculi infection.
Methods:
Distinct groups of adult Balb-C mice were immunosuppressed with different doses of dexamethasone (Dx, 3 or 5 mg/kg/day, intraperitoneal route - IP) and inoculated with E. cuniculi spores by IP route intraperitoneally. Control groups (inoculated animals but non-immunosuppressed and non- inoculated animals but immunosuppressed) were also used. The spores of E. cuniculi were previously cultivated in MDCK cells. The animals were sacrificed and necropsied at 7, 14, 21, 28 and 35 days post-inoculation. Tissue fragments were collected and processed for light microscopy studies, using Gram-chromotrope and hematoxylin-eosin staining techniques.
Results:
In all immunosuppressed and inoculated inoculated immunosuppressed mice,specially in those that received 5 mg/kg/day of dexamethasone, the most prominent necropsy findings were hepatomegaly and splenomegaly. The experimental inoculation resulted in a disseminated non-lethal infection, characterized by granulomatous lesions in several organs (liver, lungs, kidneys, gut and brain) but notably in the hepatic tissue. Spores of E. cuniculi were only seen in few animals treated with 5 mg/kg/day of Dx at 35 days post-infection.
Conclusions:
Microsporidiosis in Dx-immunosuppressed mice provides a useful model for studies of the microsporidial infection, resembling that one naturally occurring in immunodeficient individuals with AIDS.
Insights
Pharmacologically immunosuppressed mice with dexamethasone (Dx) developed a disseminated Encephalitozoon cuniculi infection, mimicking natural infections in immunocompromised individuals. This study establishes a valuable animal model for microsporidiosis research.
Area of Science:
- Immunology
- Parasitology
- Infectious Diseases
Background:
- Encephalitozoon cuniculi is an opportunistic pathogen affecting immunocompromised individuals, including AIDS patients.
- Developing reliable animal models is crucial for studying microsporidial infections.
Purpose of the Study:
- To establish a pharmacologically induced immunosuppressed animal model for Encephalitozoon cuniculi infection.
- To mimic natural microsporidiosis seen in immunodeficient human populations.
Main Methods:
- Balb-C mice were immunosuppressed using varying doses of dexamethasone (Dx).
- Mice were inoculated with E. cuniculi spores; control groups were maintained.
- Tissues were analyzed via light microscopy using Gram-chromotrope and H&E stains at multiple time points.
Main Results:
- Immunosuppressed and infected mice, particularly those receiving 5 mg/kg/day Dx, exhibited hepatomegaly and splenomegaly.
- A disseminated, non-lethal infection with granulomatous lesions occurred in multiple organs, notably the liver.
- E. cuniculi spores were detected in some mice treated with 5 mg/kg/day Dx at 35 days post-infection.
Conclusions:
- Dexamethasone-induced immunosuppression in mice provides a relevant model for studying microsporidiosis.
- This model closely resembles natural E. cuniculi infections in immunocompromised individuals, such as those with AIDS.