Automated home-cage monitoring as a potential measure of sickness behaviors and pain-like behaviors in LPS-treated mice

PLoS One. 2021 Aug 27;16(8):e0256706. doi: 10.1371/journal.pone.0256706. eCollection 2021.

Abstract

The use of endotoxin, such as lipopolysaccharide (LPS) as a model of sickness behavior, has attracted recent attention. To objectively investigate sickness behavior along with its pain-like behaviors in LPS-treated mice, the behavioral measurement requires accurate methods, which reflects clinical relevance. While reflexive pain response tests have been used for decades for pain assessment, its accuracy and clinical relevance remain problematic. Hence, we used automated home-cage monitoring LABORAS to evaluate spontaneous locomotive behaviors in LPS-induced mice. LPS-treated mice displayed sickness behaviors including pain-like behaviors in automated home-cage monitoring characterized by decreased mobile behaviors (climbing, locomotion, rearing) and increased immobility compared to that of the control group in both short- and long-term locomotive assessments. Here, in short-term measurement, both in the open-field test and automated home-cage monitoring, mice demonstrated impaired locomotive behaviors. We also assessed 24 h long-term locomotor activity in the home-cage system, which profiled the diurnal behaviors of LPS-stimulated mice. The results demonstrated significant behavioral impairment in LPS-stimulated mice compared to the control mice in both light and dark phases. However, the difference is more evident in the dark phase compared to the light phase owing to the nocturnal activity of mice. In addition, the administration of indomethacin as a pharmacological intervention improved sickness behaviors in the open-field test as well as automated home-cage monitoring, confirming that automated home-cage monitoring could be potentially useful in pharmacological screening. Together, our results demonstrate that automated home-cage monitoring could be a feasible alternative to conventional methods, such as the open-field test and combining several behavioral assessments may provide a better understanding of sickness behavior and pain-like behaviors in LPS-treated mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anxiety / diagnosis*
  • Anxiety / diagnostic imaging
  • Anxiety / physiopathology
  • Behavior, Animal / physiology
  • Disease Models, Animal
  • Humans
  • Illness Behavior / drug effects
  • Illness Behavior / physiology*
  • Lipopolysaccharides / toxicity
  • Locomotion / physiology
  • Mice
  • Monitoring, Physiologic*
  • Motor Activity / physiology
  • Pain / diagnosis*
  • Pain / diagnostic imaging
  • Pain / physiopathology
  • Pain Measurement / methods

Substances

  • Lipopolysaccharides

Grants and funding

This research was supported by Chulalongkorn University (to PT), the National Research Council of Thailand (IRN FY2020 507/2563) (to O.V.) and the Thailand Science Research and Innovation (TSRI) Fund (CU_FRB640001_01_33_3) (to P.R.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.