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Listeriosis in diacetoxyscirpenol-treated mice
1Veterinary Toxicology and Entomology Research Laboratory, USDA, College Station, TX 77841.
Abstract:
Mice were treated with the trichothecene mycotoxin diacetoxyscirpenol (DAS) and subsequently were inoculated intraperitoneally with Listeria monocytogenes. The effect of the mycotoxin on the course of the infection was monitored by observing the resultant mortality and the bacterial content of the spleens from inoculated mice. Mice given 3 mg of DAS/kg of body weight, PO, at days -2 and -1 before inoculation had increased mortality and splenic Listeria counts. In these mice, thymus weights were reduced, and lymphocytes were depleted from the thymus cortex and from splenic lymphoid follicles and periarteriolar lymphoid sheaths. A single dose of 4 mg of DAS/kg given on day 6 before challenge exposure did not affect mortality compared with that in nontreated controls. Mice treated with DAS and subsequently inoculated with Listeria had significantly (P = 0.006) increased neutrophil populations compared with Listeria-infected control mice.
Insights
Diacetoxyscirpenol (DAS), a mycotoxin, increased mortality and Listeria monocytogenes bacterial load in mice. DAS also caused thymus atrophy and lymphocyte depletion, impacting immune response to infection.
Area of Science:
- Immunotoxicology
- Microbiology
- Mycotoxicology
Background:
- Trichothecene mycotoxins, such as diacetoxyscirpenol (DAS), are contaminants found in food and feed.
- These mycotoxins can pose a risk to animal and human health by affecting the immune system.
Purpose of the Study:
- To investigate the immunotoxic effects of diacetoxyscirpenol (DAS) on the course of Listeria monocytogenes infection in mice.
- To determine the impact of DAS exposure on host susceptibility, mortality, and immune cell populations.
Main Methods:
- Mice were administered diacetoxyscirpenol (DAS) via oral gavage at specific time points before intraperitoneal inoculation with Listeria monocytogenes.
- Mortality rates and splenic bacterial loads were monitored to assess infection severity.
- Thymus weights and lymphocyte distribution in thymus and spleen were histologically examined.
Main Results:
- Mice treated with 3 mg/kg DAS two days before Listeria challenge exhibited increased mortality and higher splenic bacterial counts.
- DAS treatment led to reduced thymus weights and significant lymphocyte depletion in the thymus cortex and splenic lymphoid tissues.
- A single dose of 4 mg/kg DAS given six days prior to infection did not alter mortality.
- DAS-treated mice showed significantly increased neutrophil populations compared to controls.
Conclusions:
- Pre-infection exposure to diacetoxyscirpenol (DAS) at a dose of 3 mg/kg impairs the host immune response, leading to increased susceptibility to Listeria monocytogenes infection.
- DAS-induced immunosuppression is characterized by thymus atrophy, lymphocyte depletion, and altered neutrophil response.
- The timing and dosage of DAS exposure are critical factors influencing its immunotoxic effects.