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Johns Hopkins Bloomberg School of Public HealthCAAT

Animal Welfare Enhancement Awards - 2006 Recipients

Are analgesics equally efficacious in wild-type and gene knockout mouse strains?
Nicole Pucillo and Michael Blaha
 US Army Research Institute of Environmental Medicine

In our laboratory, radiotelemetry devices are routinely implanted into the peritoneal cavity of mice for the measurement of core temperature and motor activity. The main advantage of radiotelemetry over conventional methods, such as the use of rectal probes, is the elimination of stress effects that are associated with the use of the technique. For example, the insertion of rectal probes requires handling, restraint and/or anesthesia, all of which compromise normal physiological functioning of the animal. Conversely, radiotelemetry permits remote sensing of physiological variables in conscious, freely moving animals. However, a disadvantage of radiotelemetry is the requirement for an invasive surgical procedure to implant the device. To ensure the most humane treatment of mice, one must administer the most effective analgesic for surgical pain relief. Current analgesic choices are based on experimental data from wild-type mice; it is currently unknown how analgesic requirements differ in gene knockout mice (i.e., mice lacking a functional gene product in all tissues of the body). The goal of this study is to determine if indomethacin, a non-steroidal anti-inflammatory analgesic that has shown efficacy in wild-type mice, is equally efficacious in cytokine knockout mice. We will compare surgical recovery rates of two wild-type strains to those of interleukin (IL)-6 and tumor necrosis factor (TNF) knockout mice. These knockout models are expected to show differences in analgesic requirements, since IL-6 and TNF normally function as pro-inflammatory molecules.