Elevated-Plus Maze Test in Rodent Models of Stroke
At a glance
What Is the Elevated-Plus Maze Test?
The elevated plus maze is a widely used anxiety test for rodents. The maze consists of two enclosed arms and two open arms, typically arranged in a cross shape and elevated a few feet above the ground. The natural behavior of rodents in this setup, where they tend to avoid the open arms and spend more time in the enclosed arms or at the corners—reflects their innate fear of heights and open spaces, which is linked to anxiety-like behavior.
Rodents that are placed in the maze will generally show a preference for the enclosed, safer spaces, avoiding the open arms due to fear of potential threats. The amount of time spent in the open versus the closed arms, as well as the number of entries into each, are used as indicators of anxiety levels.
Fig. 1 Picture of the elevated plus maze used for testing rats. (Walf, et al., 2007)
Related Services
As a leading stroke research provider, Ace Therapeutics offers the elevated-plus maze test to evaluate anxiety in rat and mouse models of ischemic stroke. This test allows us to help clients investigate the pathology of anxiety after stroke and develop potential therapeutics.
Specific Procedures for the Elevated-Plus Maze Test
- The apparatus used for the elevated plus maze test is in the configuration of a + and comprises two open arms (25 x 5 x 0.5 cm) across from each other and perpendicular to two closed arms (25 x 5 x 16 cm) with a center platform (5 x 5 x 0.5 cm). The entire apparatus is 50 cm above the floor.
- Behavioral testing is performed between 9:00 AM and 6:00 PM. All the experimental mice or rats are transferred to the behavior testing room 30 min prior to beginning the first trial to habituate to the condition of the behavior testing room.
- Rats or mice are placed at the junction of the four arms of the maze, facing an open arm, and allowed to explore for 10 minutes. The entries/duration in each arm are recorded by a video-tracking system and observer simultaneously. Animals with low anxiety levels have a higher percentage of open-arm entrance and stay in the open arms longer.
Advantages and Disadvantages of the Elevated-Plus Maze Test
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Applications of the Elevated-Plus Maze Test in Rodent Models of Stroke
The elevated-plus maze is frequently used to assess anxiety in rodents after ischemic stroke, but studies have yielded mixed results. In a global ischemia model, ischemic rats exhibited reduced time in the open arms at day 1 post-injury but spent significantly more time in the open arms at day 5 compared to sham controls. At days 15 and 30 post-injury, no differences were observed between groups. Other studies reported increased time spent in the open arms at days 3 and 7 following global ischemia. However, in a transient global cerebral ischemia model, injured mice displayed higher anxiety levels at day 2 but not at day 7 post-stroke. Overall, a biphasic pattern of anxiety is commonly observed, with an initial increase in anxiety during the first week and a subsequent decrease in the second week. In contrast, a long-term study on MCAO mice found persistent anxiety at 9 weeks post-injury, as they spent less time in the open arms compared to sham controls. The variability in results is likely due to differences in animal species, stroke models, and testing protocols.
Fig. 2 Elevated plus maze after experimental ischemia in mice. (Hernandez-Jimenez, et al., 2017)
- Walf, A. A., & Frye, C. A. (2007). The use of the elevated plus maze as an assay of anxiety-related behavior in rodents. Nature protocols, 2(2), 322-328.
- Hernandez-Jimenez, M., et al. (2017). Test repositioning for functional assessment of neurological outcome after experimental stroke in mice. PLoS One, 12(5), e0176770.
