Automated home-cage-like monitoring for assessing innate behaviors in a murine hangover model

Abstract

The prevalence of alcohol consumption among the younger generation remains alarmingly high. A hangover is a common short-term consequence observed after consuming alcohol. To effectively study alcohol-induced hangovers, reliable and translational animal models, along with appropriate testing methods, are required. While several testing approaches have been used in hangover-induced mice, they often fail to assess innate behaviors comprehensively and are limited by short observation periods. Although existing studies have developed methods to assess hangover-related behaviors in rodents, few have focused on innate behaviors. This study aimed to establish a model for assessing the innate behaviors of hangover-induced mice using automated home-cage-like behavioral monitoring. Mice were intraperitoneally injected with ethanol at doses of 3, 2, or 1 g/kg, followed by behavioral assessments, including exploratory actions and long-term home-cage-like behaviors during both day and night phases. Results showed a significant reduction in mobile behaviors (climbing, locomotion, rearing), speed, and distance traveled, along with increased immobility in both exploratory and long-term home-cage-like assessments. Furthermore, there was a significant decrease in exploratory behaviors and long-term home-cage-like activities, which were linked to hangover symptoms. This study provides a preliminary approach for assessing hangover behaviors in mice using automated behavioral monitoring, ensuring improved animal welfare, optimised timing, and extended assessment durations. Hence, we propose automated home-cage-like behavioral assessment as an exploratory model for evaluating hangover behaviors in mice, which may serve as a useful tool for future research on the therapeutic efficacy of anti-hangover compounds.

Keywords: Automated home-cage-like monitoring; Ethanol; Exploratory behaviors; Hangover; Long-term locomotor behaviors; Motor coordination.

Fig. 1

Overview of the LABORAS automated home-cage monitoring apparatus. The setup consists of (a) a control unit, (b) a computer, (c) a measurement table, and (d) a cage.

Fig. 2

Schematic representation of the experimental design. (a) Timeline of exploratory behavior assessment followed by the hanging wire test. Mice received ethanol at 12:00 PM (ZT6) and were tested for exploratory behavior at 6:00 PM (ZT12), followed immediately by the hanging wire test to assess motor coordination. (b) Long-term home-cage-like behavioral monitoring. Mice received ethanol at 12:00 PM (ZT6), and behavior was continuously monitored for 24 h, covering both the active phase (6:00 PM–6:00 AM, ZT12–ZT24, dark phase) and the resting phase (6:00 AM–6:00 PM, ZT0–ZT12, light phase) under a 12:12 h light–dark cycle, with ZT0 defined as lights on at 6:00 AM and ZT12 as lights off at 6:00 PM.

Fig. 3

Effects of ethanol on spontaneous locomotor activity. The behavioral parameters are presented as the duration (a-d) and frequency (e-h) of exploratory behaviors, along with speed (i) and distance traveled (j). Data are presented as means ± SEM (n = 8 mice/group). Differences between groups were analyzed using one-way ANOVA followed by Dunnett’s post-hoc test. Significant differences between the vehicle group (0 g/kg) and ethanol-treated groups (1, 2, and 3 g/kg) are indicated as follows: *p < 0.05, ***p < 0.001.

Fig. 4

Position distribution of the mice on the cage. Representative traces showing the position distribution of mice within the cage for the vehicle (0 g/kg) group (a) and ethanol-treated groups (1, 2, and 3 g/kg) (b-d). The color spectrum represents activity levels, progressing from green (low activity) to red, magenta, and white (high activity). A shift toward the right on the color scale denotes a greater frequency or longer duration of activity in specific cage locations.

Fig. 5

Wire hanging latency in hangover mice and its correlation with exploratory behaviors in automated home-cage-like monitoring. (a) Wire hanging latency of mice after treatment with various doses of ethanol (b) Correlation matrix showing the relationships between exploratory behaviors and wire hanging latency. Differences between groups (n = 8 mice/group) were analyzed using one-way ANOVA, followed by Dunnett’s post-hoc test. Significant differences between the vehicle (0 g/kg) and ethanol-treated groups (1, 2, and 3 g/kg) are indicated as follows: ***p < 0.001.

Fig. 6

The effects of ethanol on the duration of home-cage-like behaviors in mice. Behaviors are presented as the duration of long-term innate behaviors, including climbing (a), locomotion (b), rearing (c), immobility (d), speed (e), and distance traveled (f). Data are presented as means ± SEM (n = 8 mice/group). Statistical analyses were performed using two-way repeated measures ANOVA followed by Šidák’s multiple comparisons test (left panels), and Student’s t-test (right panels). ***, ** and * denote significant differences at p < 0.001, p < 0.01, and p < 0.05, respectively.

Fig. 7

The effects of ethanol on the frequency of home-cage-like behaviors in mice. Behaviors are presented as the frequency of long-term innate behaviors, including climbing (a), locomotion (b), rearing (c), and immobility (d). Data are presented as means ± SEM (n = 8 mice/group). Statistical analyses were performed using two-way repeated measures ANOVA followed by Šidák’s multiple comparisons test (left panels), and Student’s t-test (right panels). ***, ** and * denote significant differences at p < 0.001, p < 0.01, and p < 0.05, respectively.