Applying refinement to the use of mice and rats in rheumatoid arthritis research

Rheumatoid arthritis (RA) is a painful, chronic disorder and there is currently an unmet need for effective therapies that will benefit a wide range of patients. The research and development process for therapies and treatments currently involves in vivo studies, which have the potential to cause discomfort, pain or distress. This Working Group report focuses on identifying causes of suffering within commonly used mouse and rat ‘models’ of RA, describing practical refinements to help reduce suffering and improve welfare without compromising the scientific objectives. The report also discusses other, relevant topics including identifying and minimising sources of variation within in vivo RA studies, the potential to provide pain relief including analgesia, welfare assessment, humane endpoints, reporting standards and the potential to replace animals in RA research

Treatment and re-characterization of mouse obstructive genitourinary syndrome

We aimed to characterize and to explore a treatment for a condition in which male mice exhibited a solid bulge in the preputial area and an inability to breed. Twenty-seven mice from several animal housing institutions in Spain were included in this study for microbiological and pathological characterization of this condition. The condition mostly affected breeding animals and was associated with the C57BL/6J genetic background. A solid, yellowish-white substance was found inside the prepuce, which displaced the penis cranially, preventing its externalization and limiting the animal's capacity to breed. This pattern was almost identical to that of post-coital vaginal plugs, suggesting that the blocking substance originated from ejaculate. Opposite to what was suggested in previous publications, the penis was completely intact in all of the cases, with no signs of mutilation or wounds. Based on our findings, we developed a surgical technique to clear the prepuce and recover breeding performance, which we tested in 15 other mice with the condition. We eliminated the blocking substance and recurrence of the condition by surgically opening the prepuce, and most of the animals recovered fertility.Peer reviewe

Side effects of pain and analgesia in animal experimentation

This review highlights selected effects of untreated pain and of widely used analgesics such as opioids, non-steroid anti-inflammatory drugs and antipyretics, to illustrate the relevance of carefully planned, appropriate and controlled analgesia for greater reproducibility in animal experiments involving laboratory rodents