Scandinavian Journal of Laboratory Animal Science

The Establishment of mutant mouse strain showing eosinophilia

Masahiro Morimoto — 2025-04-08

Eosinophilia is a pathological condition characterized by increased eosinophils in tissues and peripheral blood. The type 2 immune response causes eosinophilia, and interleukin-5 (IL-5) secreted by T helper 2 (Th2) cells is essential for increasing eosinophils. However, it is unclear whether there is another mechanism for the increase in eosinophil other than IL-5 upregulation.

The present study found high eosinophils in the ICR mice and established inbred mice with hypereosinophilia, named “Yama mouse”, through brother-sister mating.

The eosinophils in the peripheral blood of 6-week-old Yama mice were 30-fold higher than those in ICR mice, and Yama mice did not have visible lesions. The IL-5 expression had no significant difference in the spleen, mesenteric lymph nodes, or bone marrow of ICR and Yama mice.

Yama mice revealed a mechanism for increased eosinophil counts other than that of IL-5 upregulation. Yama mice exhibit eosinophilia without artificial treatment; therefore, they are a good animal model for studying allergic diseases and regenerative medicine, in which eosinophils are important.

Abstracts of scientific presentations, Scand-LAS 2023 symposium Uppsala, Sweden

Hanna-Marja Voipio — 2025-09-04

This paper is a collection of abstracts presented in the Scand-LAS symposium in Uppsala, Sweden in 25-28 April 2023.

Postmortem observations of one Arctic common eider (Somatria mollissima) and two thick-billed murres (Uria lomvia) following long-term implantation of PTT-100 satellite transmitters

Aage Kristian Olsen Alstrup — 2025-10-14

We surgically implanted a 50 g PTT-100 intracelomic in one adult female common eider (Somatria mollissima) and 29 g PTT-100 subcutaneous satellite transmitters in two adult female thick-billed murres (Uria lomvia). After 2-4 months the birds were harvested by local subsistence hunters and examined in the laboratory. The external examination of the birds did not reveal any morphological or pathological changes, while the surgical abdominal and cervical wounds seemed to heal with granulation tissue in all three birds. The necropsy showed chronic inflammation and fatty necrosis in one of the two murres, while the antenna Dacron cuffs were in skin level as originally sewn for all three birds with primary tissue heeling and no signs of inflammation. In the adult eider, few peritoneal adherences were found to the liver without additional signs of inflammation, while one murre had adherences and granulomatous tissue around the PTT and signs of severe inflammation and external rejection. These results indicate that that birds can survive implantation of transmitters, even if inflammation develops around the implants. The study points to the importance of continuously refining the techniques for implanting devices in wild birds and performing necropsies on recovered birds.

The successful introduction of an early rabbit to human habituation programme to reduce stress and aggressive behaviour

Lars Friis Mikkelsen — 2025-11-04

Rabbits as a species, are naturally overly sensitive to stress which is a source of concern and consideration for the use in research settings; both in terms of their interaction with humans, and in terms of the quality of the scientific outcome. To reduce stress and increase animal welfare, we have introduced an early rabbit/human habituation programme during the breeding and husbandry cycle; all the way from birth to when the rabbits are transported to the users. The programme consists in a holistic approach of early and positive human-rabbit bonding. It starts from birth with an impregnation phase of human contact in the nest boxes four times per week for 4 weeks. From weaning, the habituation programme continues with weekly positive interaction by individual petting outside the cage. The effect of the habituation programme was evaluated with several clinical stress indicators observed during the acclimatization period at the users. The study was designed as a double-blinded randomized protocol with rabbits being evaluated from four different breeding areas but with the habituation programme being implemented in one area only. After 16 months and with more than 2,400 rabbits evaluated, results showed a significant decrease in stress scores of rabbits being sourced from the area with the implemented habituation programme and with total disappearance of aggressive behaviours, such as biting, while initial stress scores were maintained for rabbits being sourced from the three other areas without the habituation programme.