Related Experiment Video
Updated: May 15, 2026
Modeling Multiple Sclerosis in the Two Sexes: MOG35-55-Induced Experimental Autoimmune Encephalomyelitis
Published on: October 13, 2023
Differences in susceptibility to okadaic acid, a diarrhetic shellfish poisoning toxin, between male and female mice
1Division of Biomedical Food Research, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan. hodaka@nihs.go.jp
Abstract:
The mouse bioassay (MBA) for diarrhetic shellfish poisoning (DSP) toxins has been widely used in many countries of the world. In the Japanese and EU methods, male mice are designated to be used for MBA. Female mice were described to be less susceptible than male mice. To the best of our knowledge, however, there have been no reports on the details of sex differences in susceptibility to DSP toxins. In this study, we investigated whether, and to what extent, female mice are less sensitive to DSP toxins. A lethal dose of okadaic acid (OA), one of the representative DSP toxins, was injected intraperitoneally into mice. The mice were observed until 24 hours after injection. Both male and female mice of ICR and ddY strains, which are designated in the Japanese official method, were compared. All the mice were four weeks old and weighed 18-20 g. The experiments were repeated twice. The lethality was 70%-100%. Survival analysis showed no sex differences in susceptibility to OA, but ICR female mice showed significant resistance compared with other groups in one out of two trials. These results indicate that sex differences were not clear but, nonetheless, male mice showed more stable results.
Insights
This study investigated sex differences in mouse susceptibility to diarrhetic shellfish poisoning (DSP) toxins. Results showed no clear sex differences, though male mice yielded more consistent outcomes in the mouse bioassay (MBA).
Area of Science:
- Toxicology
- Animal Science
- Biochemistry
Background:
- The mouse bioassay (MBA) is a standard method for detecting diarrhetic shellfish poisoning (DSP) toxins.
- Current protocols often specify male mice, with female mice presumed less susceptible.
- Detailed data on sex-specific sensitivity to DSP toxins remains limited.
Purpose of the Study:
- To investigate and quantify potential sex differences in mouse sensitivity to okadaic acid (OA), a key DSP toxin.
- To compare the susceptibility of male and female mice across different strains (ICR and ddY).
Main Methods:
- Intraperitoneal injection of lethal doses of okadaic acid (OA) into four-week-old male and female ICR and ddY mice.
- Observation of mice for 24 hours post-injection to determine lethality.
- Statistical analysis of survival data to identify sex- and strain-specific differences.
Main Results:
- Survival analysis revealed no definitive sex differences in susceptibility to OA.
- ICR female mice exhibited significant resistance in one of two experimental trials.
- Male mice demonstrated more stable and consistent results across trials.
Conclusions:
- Sex differences in susceptibility to OA are not clearly established, challenging previous assumptions.
- While not definitively less sensitive, female mice may exhibit variable responses.
- Male mice provide more reliable and reproducible results for DSP toxin detection via MBA.
