Comparison of the respiratory effects of commonly utilized general anaesthesia regimes in male Sprague-Dawley rats

Bence Ballók; Álmos Schranc; Ibolya Tóth; Petra Somogyi; József Tolnai; Ferenc Peták; Gergely H Fodor

doi:10.3389/fphys.2023.1249127

Comparison of the respiratory effects of commonly utilized general anaesthesia regimes in male Sprague-Dawley rats

Front Physiol. 2023 Sep 18:14:1249127. doi: 10.3389/fphys.2023.1249127. eCollection 2023.

Authors

Bence Ballók¹, Álmos Schranc^{1

2}, Ibolya Tóth¹, Petra Somogyi^{1

3}, József Tolnai¹, Ferenc Peták¹, Gergely H Fodor¹

Affiliations

¹ Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.
² Unit for Anaesthesiological Investigations, Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergency Medicine, University of Geneva, Geneva, Switzerland.
³ Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary.

Abstract

Background: Respiratory parameters in experimental animals are often characterised under general anaesthesia. However, anaesthesia regimes may alter the functional and mechanical properties of the respiratory system. While most anaesthesia regimes have been shown to affect the respiratory system, the effects of general anaesthesia protocols commonly used in animal models on lung function have not been systematically compared. Methods: The present study comprised 40 male Sprague-Dawley rats divided into five groups (N = 8 in each) according to anaesthesia regime applied: intravenous (iv) Na-pentobarbital, intraperitoneal (ip) ketamine-xylazine, iv propofol-fentanyl, inhaled sevoflurane, and ip urethane. All drugs were administered at commonly used doses. End-expiratory lung volume (EELV), airway resistance (Raw) and tissue mechanics were measured in addition to arterial blood gas parameters during mechanical ventilation while maintaining positive end-expiratory pressure (PEEP) values of 0, 3, and 6 cm H₂O. Respiratory mechanics were also measured during iv methacholine (MCh) challenges to assess bronchial responsiveness. Results: While PEEP influenced baseline respiratory mechanics, EELV and blood gas parameters (p < 0.001), no between-group differences were observed (p > 0.10). Conversely, significantly lower doses of MCh were required to achieve the same elevation in Raw under ketamine-xylazine anaesthesia compared to the other groups. Conclusion: In the most frequent rodent model of respiratory disorders, no differences in baseline respiratory mechanics or function were observed between commonly used anaesthesia regimes. Bronchial hyperresponsiveness in response to ketamine-xylazine anaesthesia should be considered when designing experiments using this regime. The findings of the present study indicate commonly used anaesthetic regimes allow fair comparison of respiratory mechanics in experimental animals undergoing any of the examined anaesthesia protocols.

Keywords: animal model; general anaesthesia; lung function; rat; respiratory mechanics.

Grants and funding

This work was supported by the Hungarian Basic Research Council Grant (OTKA-NKFIH FK134274 and K138032) and the UNKP-22-3-SZTE-236 New National Excellence Program of the Ministry for Innovation and Technology of the Hungarian Government.