Rheumatoid arthritis

An animal experiencing unmanaged pain may exhibit altered behavioural, metabolic and immune responses, potentially leading to less reliable data. Analgesia can be provided in rheumatoid arthritis studies with careful protocol design. For example, agents such as gabapentin, ketorolac and paracetamol can be administered during peak inflammatory periods without affecting data obtained later in the disease progression. All pain relief protocols should be developed in collaboration with researchers, animal technologists and veterinarians.

Helpful indicators include weight loss, body condition scoring, coat condition and ‘pain faces’ (or ‘grimace scales’). Those more specific to arthritis include abnormal gaits (e.g. prolonged failure to bear weight on a limb, or ‘sledging’ - dragging the hindquarters), paw swelling and ulceration. Input from researchers, animal technologists, and veterinarians helps to ensure welfare assessment that is tailored to the species, strain, and experimental protocol.

Minimise variation by standardising animal characteristics like strain and age, ensuring that both sexes are represented as appropriate. Ensure consistent housing conditions and environmental stimulation to reduce stress. Maintain consistency in experimental procedures, including precise inducer administration and standardised welfare assessment. Very importantly, ensure randomisation and blinding to reduce bias and improve translatability.

Factors that may increase harms to animals in rheumatoid arthritis studies include:

• whether arthritis will be spontaneous or induced;
• any need to boost or synchronise;
• the number and frequency of interventions, including anaesthesia;
• latency to onset of severe outcomes and their subsequent duration;
• the number of joints affected;
• the maximum level of suffering experienced by the animal;
• lifetime suffering experienced by the animal;
• potential to provide analgesia;
• the numbers of animals required.