Towards substitution of invasive telemetry: An integrated home cage concept for unobtrusive monitoring of objective physiological parameters in rodents (pdf)

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Towards substitution of invasive telemetry: An integrated home cage concept for unobtrusive monitoring of objective physiological parameters in rodents

PLOS ONE RESEARCH ARTICLE Towards substitution of invasive telemetry: An integrated home cage concept for unobtrusive monitoring of objective physiological parameters in rodents Lucas Mösch ID1☯*, Janosch Kunczik1☯, Lukas Breuer1, Dorit Merhof2, Peter Gass3, Heidrun Potschka4, Dietmar Zechner5, Brigitte Vollmar5, René Tolba6, Christine Häger7, André Bleich7, Michael Czaplik1, Carina Barbosa Pereira1 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Mösch L, Kunczik J, Breuer L, Merhof D, Gass P, Potschka H, et al. (2023) Towards substitution of invasive telemetry: An integrated home cage concept for unobtrusive monitoring of objective physiological parameters in rodents. PLoS ONE 18(9): e0286230. https://doi.org/ 10.1371/journal.pone.0286230 Editor: Dragan Hrncic, Belgrade University Faculty of Medicine, SERBIA Received: May 10, 2023 Accepted: August 14, 2023 Published: September 7, 2023 Copyright: © 2023 Mösch et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Access to all the specifications, software, system configurations, and 3D models presented is granted via https:// github.com/FOR2591/homecage Minimal dataset available at: https://doi.org/10.5281/zenodo. 8187356. 1 Department of Anaesthesiology, Faculty of Medicine, RWTH Aachen University, Aachen, North RhineWestphalia, Germany, 2 Chair of Image Processing, Faculty of Computer and Data Science, Universität Regensburg, Regensburg, Bavaria, Germany, 3 Research Group Animal Models in Psychiatry, Department of Psychiatry and Psychotherapy, Central Institute of Mental Health Mannheim, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Baden Württemberg, Germany, 4 Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Bavaria, Germany, 5 Rudolf-ZenkerInstitute of Experimental Surgery, University Medical Centre Rostock, Rostock, Mecklenburg-Western Pomerania, Germany, 6 Institute of Laboratory Animal Science, Faculty of Medicine, RWTH Aachen University, Aachen, North Rhine-Westphalia, Germany, 7 Institute for Laboratory Animal Science, Hannover Medical School, Hannover, Lower Saxony, Germany ☯ These authors contributed equally to this work. * Abstract This study presents a novel concept for a smart home cage design, tools, and software used to monitor the physiological parameters of mice and rats in animal-based experiments. The proposed system focuses on monitoring key clinical parameters, including heart rate, respiratory rate, and body temperature, and can also assess activity and circadian rhythm. As the basis of the smart home cage system, an in-depth analysis of the requirements was performed, including camera positioning, imaging system types, resolution, frame rates, external illumination, video acquisition, data storage, and synchronization. Two different camera perspectives were considered, and specific camera models, including two near-infrared and two thermal cameras, were selected to meet the requirements. The developed specifications, hardware models, and software are freely available via GitHub. During the first testing phase, the system demonstrated the potential of extracting vital parameters such as respiratory and heart rate. This technology has the potential to reduce the need for implantable sensors while providing reliable and accurate physiological data, leading to refinement and improvement in laboratory animal care. Funding: The authors declare funding in part from the German Research Foundation (Deutsche Forschungsgemeinschaft—DFG; FOR-2591, 321137804, DM: ME 3737/18-1, PG: GA 427/12-2, PLOS ONE | https://doi.org/10.1371/journal.pone.0286230 September 7, 2023 1 / 19 PLOS ONE HP: PO 681/9-1 and PO 681/9-2, DZ: ZE 712/1-1, ZE 712/1-2, BV: VO 450/15-1, VO 450/15-2, RT: TO 542/5-1 and 5-2, TO 542/6-1 and 6-2, CH: HA 6483/1-2, AB: BL953/10-1 and 10-2, BL953/11-1 and 11-2, MC: CZ 215/3-2, CBP: BA 7115/1-2) without the involvement of the funders in study design, data collection, data analysis, manuscript preparation or decision to publish. Competing interests: The authors have declared that no competing interests exist. Home cage concept for unobstrusive monitoring of rodents Introduction The fundamental aim of biomedical research is to understand the etiology and pathophysiology of diseases so that strategies and recommendations might be developed for their prevention and treatment [1–3]. Animal experiments played a significant role in this understanding and contributed to the tremendous medical progress achieved to date [4]. However, ethical concerns regarding animal pain, distress, and death during scientific experiments have long been a highly controversial topic [5]. Several alternative methods have been proposed to overcome the drawbacks inherent in animal studies and to avoid unethical procedures. The 3Rs principle by Russell and Burch (1959)—Replace, Reduce, and Refine—has been widely incorporated into animal research laws and regulations to maintain high animal welfare standards [6]. These principles promote alternative methods and reduce the number of animals used in scientific research while refining the trials to ensure the most efficient and least severe procedures [5]. In addition, animals in distress, experiencing pain, or under excessive stress may exhibit modified physiological and psychological responses, significantly impacting the quality of data obtained [7]. As a result, investigators are advised to recognize situations and procedures that may adversely affect the animals. Multiple indicators are recommended to avoid interpretation errors and provide a comprehensive understanding of an animal’s welfare [8, 9]. Importantly, clear concepts of combining these indicators to assess the severity of procedures objectively have been developed [10]. Appropriate welfare indicators, both psychological and physiological, may be divided into six ‘high-level’ categories: • Appearance, including body, coat and skin conditions (e.g., unkempt coat, porphyrin staining); • Body functions, such as changes in body weight and temperature as well as changes in heart rate (HR), respiratory rate (RR) and character, blood pressure and stress hormone levels; • Environment within the cage (such as nest quality, consistency of faeces); • Behaviours, including social interaction, posture, gait, lameness, and undesirable behaviour (e.g., excessive licking, scratching, apathy or withdrawal, increased aggression, stereotypic behaviour); • Procedure-specific indicators (for instance, tumour size in cancer experiments); • Free observations (subjective analysis of the researcher) [11, 12]. To date, the assessment of welfare indicators has been sporadic in both day-to-day work and during anima (...truncated)