Neoplasia and pain in laboratory animals

Tumour-bearing laboratory animals, and mice in particular, are widely used by cancer research scientists as model systems. Although most researchers agree that their investigations cause pain and distress to the animals involved, no systematic objective studies have been undertaken to investigate neoplasia-induced pain in laboratory animals. The lack of information concerning the level of pain experienced by the animals has resulted in uncertainties as to whether this is a significant welfare concern. It also hampers application of humane end-points and makes cost-benefit analyses difficult. The proposed research aims to evaluate cancer pain in rodents and to develop some means of resolving this problem, for example, by providing a practically useful scheme for pain measurement. Different tumour models will be studied to identify those of greatest concern. Having defined circumstances under which pain could occur, pain severity and duration will be evaluated, along with strategies for pain avoidance or alleviation. The results of this project will be central to attempts to refine the use of animals in cancer research, and to balance the costs and benefits of research involving rodent tumour models. In addition, studying a range of different animal models of neoplasia will identify cancer pain models that could be used in developing improved analgesic strategies in humans. Specifically the research will test 4 hypotheses: 1. Animals tumour models are associated with host pain; 2. Host pain can be detected by analyses of behaviour; 3. Behavioural changes, and by implication pain, can be attenuated by analgesics; 4. Tumour growth and behavioural changes will be associated with the development of hyperalgesia and allodynia; 5. Progression of tumour growth will be associated with increased self-administration of analgesics. An important outcome of the project will be the development of another CD (similar in content to one we have produced on post-operative pain in rats) containing illustrative material to assist research groups in assessing the welfare of mice and rats with neoplasia.

• Further Funding: NC3Rs Project Grant, Assessing the welfare of mice used in cancer research, April 2010, £380,741