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Experimental production of actinomycetoma in BALB/c mice
Abstract:
Chronic actinomycetoma associated with grain production was induced in BALB/c mice by subcutaneous inoculation of live Nocardia brasiliensis in Freund incomplete adjuvant into the hind footpads. Similar inoculation of N. asteroides and N. caviae resulted in local tumor formation which healed spontaneously after 5 months, the disease disseminating into the peritoneum, where masses or organisms could be detected. Grains were recovered from superficial skin lesions of N. caviae, but not from the N. asteroides-infected mice. Mycetoma lesions, appearing as early as 1 month after inoculation of 1.2 X 10(7) colony-forming units of N. brasiliensis per ml or as late as 3 months with inoculation of 1.0 X 10(5) colony-forming units per ml, became persistent and were readily detectable even 6 months after inoculation. No spontaneous healing occurred, and grains were recovered at different stages of the disease. Saline suspensions of N. brasiliensis also produced typical mycetoma lesions, although the incubation period was ca. 6 months. Adjuvant addition appeared to accelerate the onset of the disease. Experimental production of actinomycetoma in laboratory animals allows the study of many unanswered aspects of the disease and also provides a suitable model for therapeutic trials in the search for new and more effective chemotherapeutic agents.
Insights
Researchers induced chronic actinomycetoma in mice using Nocardia brasiliensis, creating a model to study this fungal infection and test new treatments. This experimental model shows persistent lesions and aids in developing better therapeutic agents.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Animal Models
Background:
- Actinomycetoma is a chronic fungal infection often associated with agricultural environments.
- Understanding the pathogenesis and developing effective treatments for actinomycetoma remain significant challenges.
Purpose of the Study:
- To establish a reproducible experimental model of actinomycetoma in BALB/c mice.
- To investigate the disease progression and characteristics of Nocardia species infections.
- To provide a platform for evaluating potential chemotherapeutic agents.
Main Methods:
- Subcutaneous inoculation of live Nocardia brasiliensis, Nocardia asteroides, and Nocardia caviae into the hind footpads of BALB/c mice.
- Use of Freund incomplete adjuvant to enhance disease induction.
- Monitoring lesion development, persistence, and presence of grains over six months.
- Comparison of infections induced with adjuvant versus saline suspensions.
Main Results:
- Nocardia brasiliensis successfully induced persistent chronic actinomycetoma lesions in mice, with varying incubation periods based on inoculum size.
- Nocardia asteroides and Nocardia caviae caused localized lesions that healed spontaneously but led to peritoneal dissemination.
- Grains were recovered from N. brasiliensis and N. caviae lesions, but not N. asteroides.
- Adjuvant significantly accelerated the onset of actinomycetoma compared to saline suspensions.
Conclusions:
- The experimental model effectively replicates chronic actinomycetoma caused by Nocardia brasiliensis.
- This model allows for detailed study of disease progression and is suitable for therapeutic trials.
- Further research using this model can lead to the development of novel chemotherapeutic strategies for actinomycetoma.