Refining cage change routines: comparison of cardiovascular responses to three different ways of cage change in rats

Abstract

Cage change is one of the unavoidable routines in laboratory rodent care. However, cage change disrupts the rodents' olfactory environment and can evoke stress reactions. In this study, the short-term cardiovascular responses to three different cage change procedures were compared with telemetric monitoring. These procedures were: placing the rats into a new, clean cage (NEW), transferring the old cage lid into the clean cage (LID) and transferring an enrichment object into the clean cage (ENR) with the animals. Seven outbred rats (four Hsd:Sprague-Dawley and three HsdBrlHan:WIST) were instrumented with telemetric transmitters. The reactions were recorded during the 24 h following the cage change procedures. All cage change procedures (and also simple handling) caused elevated heart rate and mean arterial pressure levels for up to 5 h after the procedure, with the largest effect seen during the first hour. The reactions observed after cage change were significantly (P , 0.05) greater than those observed after simple handling. The reactions after NEW were significantly higher than the reactions after ENR or LID, though the results were dependent on the stock. In Wistar rats the LID procedure resulted in smaller reactions than ENR. In Sprague-Dawley rats, the differences between ENR and LID were not so clear, but the transfer of scent-marked material into the new cage decreased the reactions compared with the NEW procedure also in this stock. Based on these results, using the old cage lid on the new cage could reduce the disturbance of cage change in rats.

Retrospective Analysis of the Effects of Identification Procedures and Cage Changing by Using Data from Automated, Continuous Monitoring

“…Although routine cage changing (that is, approximately every 14 d for mouse cages) is important for maintaining the health and hygiene of animals, this husbandry procedure is associated with a number of behavioral and physiologic effects in rodents. Previous research is rich with examples, including: 1) increases in heart rate and mean arterial pressure; 1,11,25 2) aggression among male cage mates; 5 3) elevations in locomotion and other spontaneous activities; 28 4) disruptions in sleep and circadian rhythms; 12,27 and 5) elevated stress responses. 26,29 Therefore, there is growing interest not only to understand the effects and repercussions of animal responses to cage changes but also to reduce them.…”

Does the Stress Inherent to Laboratory Life and Experimentation on Animals Adversely Affect Research Data?

“…While there is evidence that this might be the case to some degree and in some circumstances, there is also substantial evidence to the contrary -i.e. that stress may become worse due to repeat exposures; that habituation/desensitisation applies to only some types of stressor and not others; that while some indicators of stress may decrease, others do not, confounding the issue; and so on (see various examples [7][8][9][10][11][12][13] ).…”

APOE4 Promotes Tonic-Clonic Seizures, an Effect Modified by Familial Alzheimer’s Disease Mutations

“…It is also conceivable that distinct neural circuits are recruited between seizures induced during cage changes and elicited by PTZ. Stimuli produced during cage changes (sounds, new environment, handling) results in stress and anxiety in rodents, as evident from changes in behavior, hormone levels and heart rates (Duke et al, 2001;Meller et al, 2011;Rasmussen et al, 2011). In fact, placing a mouse in a new environment in ways that are similar, if not identical to the cage change procedure in our study is used as an assay of tonic-clonic seizures susceptibility (Todorova et al, 1999;Leussis and Heinrichs, 2006;Hunter et al, 2012;Qi et al, 2018).…”