Non-aversive handling in laboratory animals and its effects on depressive-like and anxiety-related behaviors: a scoping review.

Stress is an adaptive response to environmental demands, but increased intensity and frequency can lead to impaired adaptive functions. Stress is considered a risk factor for Major Depressive Disorder, a multifactorial disorder that often coexists with anxiety. Picking up laboratory mice by the tail is the most common method for animal capture and may create background stress. Non-aversive handling (NAH) includes capturing the animal with the help of a tunnel or by capturing the animal with cupped hands. Given the importance of stress-induced models in the investigation of depressive-like and anxiety-related behaviors, we conducted a literature review to investigate the current knowledge on the behavioral effects of NAH in laboratory animals. While the ability of NAH to counteract depressive-like behavior has yielded mixed results, its ability to induce anxiolytic-like effects in mice has been confirmed by several studies. Some of the studies also investigated the impact of NAH on stress-related molecules (e.g. corticosterone) and physiological parameters (i.e. adrenal gland mass and body weight). The anxiolytic-like effect elicited by NAH seems to be well established in the literature, but little is known about the biochemical pathways underlying it and its antidepressant potential.