Environmental Enrichment and Rat Liver Proteomics

We aimed to address the challenge of accommodating an increasing demand for aged laboratory animals in the context of rising elderly population and research on aging-related diseases. We developed a cost-effective environmental enrichment method and assessed its impact on metabolic changes in Sprague Dawley rats' livers as a proof-of-concept organ. Twenty-four male rats were divided into four groups, with two kept in standard cages and two in modified rabbit cages. Half of each type of cage group received additional enrichment through weekly playtime in a larger cage. Over six months, the rats' weight gain was consistent across all groups, and corticosterone levels did not significantly differ. However, the control group had significantly lower DHEA and Testosterone levels at the study's end. Rats in enriched environments exhibited less distress during inspections and were more resistant to accepting treats. Animals accustomed to playpen time left their cages more easily. Overall, the study demonstrated that refining husbandry for aging rats is both simple and cost-effective, without detrimental effects on stress levels, development, or liver metabolism.