Stressed out: providing laboratory animals with behavioral control to reduce the physiological effects of stress.

Laboratory animals experience a large amount of environmental stress. An animal's environment can include both physiological and social stressors that may require an animal to adapt to maintain allostatic balance. For example, thermal stress can lead to changes in behavior, reproduction and immune function, which has been detrimental to cancer modeling in mice. Chronic uncontrollable stress is widely acknowledged for its negative alterations to physiology. However, there is a lack in the understanding of how the laboratory environment affects animal physiology and behavior, particularly as it relates to characteristics of the human disease being modeled. Given the evidence on how stressors affect physiology, it is clear that efforts to model human physiology in animal models must consider animal stress as a confounding factor. We present evidence illustrating that providing captive animals with control or predictability is the best way to reduce the negative physiological effects of these difficult-to-manage stressors.