Conducting and automating Morris water maze test under SPF conditions

Abstract

The Morris water maze is the basic test to study spatial learning and memory in laboratory rodents. It is part of the set of tests necessary for behavioral phenotyping of mutant and transgenic mice. However, the SPF conditions impose very strict regulations on pathogen control, which hinders performance of this test. Another problem is a low contrast of a white animal on the whitened water surface, interfering with automated animal tracking. A unique installation based on EthoStudio has been designed at the Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences and Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences. This tool automates the tracking of mice of any coat color under SPF conditions and comprises a plastic water tank (110 × 40 cm), a digital camera, and a light source. The water for the tank is sterilized using a Van Erp Blue Lagoon UV-C Tech 15000 ultraviolet decontaminator. The image of an animal is processed in a frame-by-frame manner using the EthoStudio software; the following parameters are calculated: escape latency, path length, cumulative distance to the platform, and the time spent in the sectors of tank. This installation has allowed us to study the spatial learning and memory in C57BL/6 and C57BL/6/Kaiso mice; in the latter strain, the gene encoding the methyl-DNA binding Kaiso protein is knocked out. It has been shown that the mice of these strains are capable of learning to find the platform in the Morris water maze and remember the location of the platform for at least the next four days.