Enriched environment prevents hypernociception and depression-like behavior in a psychiatric disorder and neuropathic pain comorbidity experimental condition

Abstract

Pain is a multifactorial debilitating condition associated with some psychiatric comorbidities such as generalized anxiety and depression. Concerning pharmacological treatment, which is often inefficient or associated with intense side effects, the physical and social context may be fundamental for patient's health improvement. In this sense, we sought to assess the impact of an enriched environment (EE) on neuropathic pain (NP) and depression comorbid. For this purpose, mice exposed to EE or non-enriched conditions for three weeks were submitted to either a chronic constriction injury (CCI) of the ischiadicus nervus or a sham procedure. After three weeks of EE or non-enriched exposition, allodynia (recorded by von Frey and acetone tests), hyperalgesia (recorded by hot plate test), despair behavioral response (recorded by tail suspension test), and apathy (recorded by sucrose spray test) were evaluated. Mice submitted to CCI procedure showed increased rates of hyperalgesia and allodynia, as well as depression-like behaviors compared to the sham procedure-submitted mice. Exposure to EE significantly increased pain thresholds and significantly diminished depression-related behaviors. These findings suggest that the sensory, physical, and social context can be an extra tool for controlling not only sensory-discriminative pain but also emotional pain-related psychiatric comorbidities, such as depression.