Conducting and automating the water Morris maze test in SPF conditions

Abstract

The water Morris maze is the basic test to study the spatial ability to learn as well as spatial memory in laboratory rodents. It is a part of a series of tests necessary for behavioral phenotyping of mutant and transgenic mice. At the same time, conducting this test in SPF conditions must comply with very strict regulations concerning pathogen control. A white animal on the surface of whitened water is low contrast and this does not allow the animal to be traced automatically, which represents yet another major problem. A unique installation based on EthoStudio has been developed at the Institute of Cytology and Genetics SB RAS and the Institute of Automation and Electrometry SB RAS. This installation automates the process of tracing mice of any coat color in SPF conditions. This includes a setup to install a plastic water reservoir (110×40 cm), a digital camera and a light source. Water to fill the reservoir was sterilized using a Van Erp Blue Lagoon UV-C Tech 15000 ultraviolet decontaminator. The image of an animal was processed in a frame-by-frame fashion using the EthoStudio program, with the following parameters calculated: latent release time, route covered, cumulative distance to the platform and the time spent in the reservoir sectors. With this installation, we were able to study the spatial ability to learn and spatial memory in mice of the C57BL/6 strain and in mice of the C57BL/6/ Kaiso strain developed on the C57BL/6 background, with the gene encoding the methyl-DNA binding Kaiso protein knocked-out. It has been demonstrated that mice of these strains are able to learn to find the platform in the water Morris maze and have the location of the platform in their memory for at least the next four days.

Keywords

• water morris maze
• spatial memory
• measurement automation
• knockout mice