Rodent Shelter

Background

Rodents undergo surgical procedures in studies investigating disease mechanisms, the efficacy and safety of new treatments and to enable monitoring of physiological parameters such as heart rate and blood pressure. Post-operative care is critical to minimise pain and distress and aid recovery. This includes providing analgesia, a source of warmth and shelter, palatable food and close regular observations of animal behaviour and vital signs.

Following surgery, most rodents are returned to their social groups as soon as they are sufficiently recovered. In some circumstances it can be necessary to single house animals for a short period of time to mitigate against damage to sutures, wounds and implants by cage mates. When rodents are singly housed directly after surgery, enrichment items are often removed to avoid injuries and enable better monitoring. The post-operative housing environment is important as it can influence recovery in mice [1] and may induce stress. For example, a change in bedding material can affect post-surgery blood pressure [2, 3].

Rodents have a large surface area to body weight ratio, which means they lose body heat rapidly and are susceptible to hypothermia. Following anaesthesia and surgical procedures, their ability to regulate their body temperature is reduced. Providing thermal support during this time is critical to mitigate against the risk of hypothermia and aid the animal’s recovery [4-8]. Warmth is often provided by externally powered heat pads placed under the cage. However, these cannot be used for cages kept in racks (e.g. individually ventilated cages and large rat cages such as high houses or double decker cages). There is a need for an easy-to-use solution for providing shelter and warmth in any cage type for post-operative care.  

3Rs benefits

Annually at AstraZeneca, over 200 rodents undergo surgical procedures and require post-operative care. The development of a small, easy-to-use, warming shelter would improve post-operative recovery, monitoring and pain management, as well as scientific outcomes. Improved recovery could also enable:

• A reduction in rodent use, especially for advanced surgical models, where extra animals are added due to the uncertainty around post-operative recovery.
   
• Returning animals to their social groups more quickly, minimising the time spent singly-housed.

The shelter would have broad applicability across the bioscience sector where surgical animals are used including academia, contract research organisations and the pharmaceutical industry. It could also be used for non-surgical models such as cold sensitive strains (e.g. BTBR ob/ob mice and nude mice) and for mice required to be single housed for specific measurements such as food intake or in cases of male mice incompatibility. Additionally, the shelter could be used by veterinary clinics in the care of small animal pets, where there is increasing demand for veterinary care and surgical intervention.

References

1. Pham TM et al. (2010). Housing environment influences the need for pain relief during post-operative recovery in mice. Physiol Behav 99(5):663-8. doi: 10.1016/j.physbeh.2010.01.038
    
2. Baran WS (2010). Post-surgical environmental enrichment in rodents, Enrichment Record enrichmentrecord.com 
    
3. Terreros D (2010). Effect of bedding type on blood pressure lean Zucker rat. El Paso
    
4. Institute for Laboratory Animal Research (2011). Guide for the care and use of laboratory animals, 
   8th ed. Washington (DC): National Academies Press.
    
5. Tashiro M et al. (2020). Duration of thermal support for preventing hypothermia induced by anesthesia with medetomidine-midazolam-butorphanol in mice. J Vet Med Sci 82(12):1757-62. doi: 10.1292%2Fjvms.20-0256
    
6. Beale CN et al. (2018). Use of Air-activated Thermal Devices during Recovery after Surgery in Mice. J Am Assoc Lab Anim Sci 57(4):392-400. doi: 10.30802%2FAALAS-JAALAS-17-000077
    

7. Caro AC (2013). Comparison of thermoregulatory devices used during anesthesia of C57BL/6 mice and correlations between body temperature and physiologic parameters. J Am Assoc Lab Anim Sci 52(5):577-83. PMID: 24041214

8. Bagis H (2004) Exposure to warmer postoperative temperatures reduces hypothermia caused by anaesthesia and significantly increases the implantation rate of transferred embryos in the mouse. Lab Anim 38(1):50-4. doi: 10.1258/00236770460734399

9. Weary DM (2009) Board-invited review: Using behavior to predict and identify ill health in animals. J Anim Sci 87(2):770-7. doi: 10.2527/jas.2008-1297

Assessment information

Review Panel membership

This Challenge is now closed for applications. 

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Rodent Shelter key documents:

Rodent Shelter key dates: