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Roschke NN, Hillebrandt KH, Polenz D, Klein O, Gassner JMGV, Pratschke J, Krenzien F, Sauer IM, Raschzok N, Moosburner S. Optimizing environmental enrichment for Sprague Dawley rats: Exemplary insights into the liver proteome. PLoS One 2024; 19:e0297497. [PMID: 38635534 PMCID: PMC11025844 DOI: 10.1371/journal.pone.0297497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 01/07/2024] [Indexed: 04/20/2024] Open
Abstract
BACKGROUND Considering the expected increase in the elderly population and the growing emphasis on aging-related biomedical research, the demand for aged laboratory animals has surged, challenging established husbandry practices. Our objective was to establish a cost-effective method for environmental enrichment, utilizing the liver as a representative organ to assess potential metabolic changes in response to differing enrichment levels. METHODS We conducted a six-month study involving 24 male Sprague Dawley rats, randomly assigned to four environmental enrichment groups. Two groups were housed in standard cages, while the others were placed in modified rabbit cages. Half of the groups received weekly playtime in an activity focused rat housing unit. We evaluated hormone levels, playtime behavior, and subjective handling experience. Additionally, liver tissue proteomic analysis was performed. RESULTS Initial corticosterone levels and those after 3 and 6 months showed no significant differences. Yet, testosterone levels were lower in the control group by the end of the study (p = 0.007). We observed 1871 distinct proteins in liver tissue, with 77% being common across groups. In gene ontology analysis, no specific pathways were overexpressed. In semiquantitative analysis, we observed differences in proteins associated in lipid metabolism such as Apolipoprotein A-I and Acyl-CoA 6-desaturase, which were lower in the control group (p = 0.024 and p = 0.009). Rats in the intervention groups with weekly playtime displayed the least amount of reported distress during inspection or upon room entry and were less prone to accepting treats. Removing animals from their enclosure was most effortless for those in the large cage group. Over time, there was a decrease in conflicts among rats that interacted only twice weekly during playpen time. DISCUSSION In summary, refining husbandry practices for aging rats is both simple and budget-friendly, with no apparent adverse effects on stress levels, animal development, or relevant metabolic changes in the liver.
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Affiliation(s)
- Nathalie N. Roschke
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Karl H. Hillebrandt
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité –Universitätsmedizin Berlin, BIH Academy, Clinician Scientist Program, Berlin, Germany
| | - Dietrich Polenz
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Oliver Klein
- Berlin Institute of Health, Center for Regenerative Therapies, Berlin, Germany
| | - Joseph M. G. V. Gassner
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité –Universitätsmedizin Berlin, BIH Academy, Clinician Scientist Program, Berlin, Germany
| | - Johann Pratschke
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Felix Krenzien
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité –Universitätsmedizin Berlin, BIH Academy, Clinician Scientist Program, Berlin, Germany
| | - Igor M. Sauer
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nathanael Raschzok
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité –Universitätsmedizin Berlin, BIH Academy, Clinician Scientist Program, Berlin, Germany
| | - Simon Moosburner
- Department of Surgery, Experimental Surgery, Charité –Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Berlin Institute of Health at Charité –Universitätsmedizin Berlin, BIH Academy, Clinician Scientist Program, Berlin, Germany
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Nakagawa S, Lagisz M, Yang Y, Drobniak SM. Finding the right power balance: Better study design and collaboration can reduce dependence on statistical power. PLoS Biol 2024; 22:e3002423. [PMID: 38190355 PMCID: PMC10773938 DOI: 10.1371/journal.pbio.3002423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024] Open
Abstract
Power analysis currently dominates sample size determination for experiments, particularly in grant and ethics applications. Yet, this focus could paradoxically result in suboptimal study design because publication biases towards studies with the largest effects can lead to the overestimation of effect sizes. In this Essay, we propose a paradigm shift towards better study designs that focus less on statistical power. We also advocate for (pre)registration and obligatory reporting of all results (regardless of statistical significance), better facilitation of team science and multi-institutional collaboration that incorporates heterogenization, and the use of prospective and living meta-analyses to generate generalizable results. Such changes could make science more effective and, potentially, more equitable, helping to cultivate better collaborations.
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Affiliation(s)
- Shinichi Nakagawa
- Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
- Theoretical Sciences Visiting Program, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Malgorzata Lagisz
- Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
- Theoretical Sciences Visiting Program, Okinawa Institute of Science and Technology Graduate University, Onna, Japan
| | - Yefeng Yang
- Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | - Szymon M. Drobniak
- Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
- Institute of Environmental Sciences, Jagiellonian University, Kraków, Poland
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