Environmentally enriched housing conditions reduce   Open  Access  the depression-inducing potential of chronic   unpredictable among Sprague-Dawley rats :

Thomas Amartey Tagoe; Aliu Zanzeh Bankah; Emmanuel Darko; Clement Asante; Andrew Lartey; Kennedy Kwami Edem  Kukuia

doi:10.46829/hsijournal.2026.3.8.1.1411-1419

Thomas Amartey Tagoe Department of Physiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana; Department of Physiology, The Accra College of Medicine, Accra, Ghana
Aliu Zanzeh Bankah Department of Physiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
Emmanuel Darko Department of Physiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
Clement Asante Department of Physiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
Andrew Lartey Department of Physiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
Kennedy Kwami Edem Kukuia Department of Medical Pharmacology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Korle Bu-Accra. Ghana

DOI: https://doi.org/10.46829/hsijournal.2026.3.8.1.1411-1419

Keywords: Environmental enrichment, chronic unpredictable mild stress (CUMS), stress resilience, anhedonia, depression

Abstract

Background: Depression remains a leading cause of global disability, with current treatments unable to meet the needs of all patients. Environmental enrichment (EE), a non-pharmacological intervention involving enhanced physical, sensory, cognitive, and social stimulation, has demonstrated potential as an alternative therapy. However, most preclinical models of depressi on, including the widely used chronic unpredictable mild stress (CUMS) paradigm, are conducted under standard housing conditions that may not reflect the actual, complex human environment.
Objective: This study evaluated the capacity of CUMS to induce depression-like behaviours in rats housed under extended EE conditions.
Methods: Twelve Sprague Dawley rats were randomly assigned to either an EE group, where they were housed under enriched housing conditions or an EE+CUMS group, where they were subject to CUMS while under enriched housing conditions. At the end of the four-week experimental period, weights were recorded alongside behavioural assessments, including the sucrose preference test (SPT), open field test (OFT), forced swim test (FST), and novel object recognition task (NORT).
Results: Findings revealed that EE+CUMS rats exhibited a cross-section of the classical signs of stress-induced depression. This included an absence of weight gain (p = 0.82), which was present in controls (p = 0.0002) and poor novel object recognition in comparison to controls (p = 0.017). Between the two groups, there were no significant differences in sucrose preference, FST or OFT performance. Furthermore, in the
OFT, locomotor activity was comparable, and both groups equally preferred peripheral over central zones.
Conclusion: Although the CUMS model impaired weight gain and memory, the classical signs of depression, such as anhedonia, anxiety and helplessness, were absent. This could be due to stress resilience conferred by enriched housing or insufficient stress from the CUMS protocol.
Further studies are required to assess the underlying neurobiological mechanisms and design a CUMS protocol capable of inducing depression under enriched housing conditions. This will contribute towards enhancing the translational relevance of preclinical studies for human depression research and treatment development.

Environmentally enriched housing conditions reduce Open Access the depression-inducing potential of chronic unpredictable among Sprague-Dawley rats

Enriched housing conditions reduce depression in rats

Abstract