Behavioral profiles of three C57BL/6 substrains

Abstract

C57BL/6 inbred strains of mice are widely used in knockout and transgenic research. To evaluate the loss-of-function and gain-of-function effects of the gene of interest, animal behaviors are often examined. However, an issue of C57BL/6 substrains that is not always appreciated is that behaviors are known to be strongly influenced by genetic background. To investigate the behavioral characteristics of C57BL/6 substrains, we subjected C57BL/6J, C57BL/6N, and C57BL/6C mice to a behavior test battery. We performed both a regular scale analysis, in which experimental conditions were tightly controlled, and large-scale analysis from large number of behavioral data that we have collected so far through the comprehensive behavioral test battery applied to 700-2,200 mice in total. Significant differences among the substrains were found in the results of various behavioral tests, including the open field, rotarod, elevated plus maze, prepulse inhibition, Porsolt forced swim, and spatial working memory version of the eight-arm radial maze. Our results show a divergence of behavioral performance in C57BL/6 substrains, which suggest that small genetic differences may have a great influence on behavioral phenotypes. Thus, the genetic background of different substrains should be carefully chosen, equated, and considered in the interpretation of mutant behavioral phenotypes.

Keywords: C57BL/6; behavior; inbred strain; mouse.

Figure 1

Physical characteristics of C57BL/6 substrains. (A–D) Regular scale analysis. (E–H) Large-scale analysis. (A,E) Body weight. (B,F) Body temperature. (C,G) Grip strength test. (D,H) Wire hang test. *p < 0.001, **p < 0.0001. Error bars indicate SEM.

Figure 2

Sensorimotor function tests of C57BL/6 substrains. (A,B) Regular scale analysis. (C,D) Large-scale analysis. (A,C) Hot plate test. C57BL/6J showed the shortest latencies in the large-scale analysis. (B,D) Rotarod test. C57BL/6J mice showed the longest latencies to fall. *p < 0.0001. Error bars indicate SEM.

Figure 3

Open field test of C57BL/6 substrains. (A–D) Regular scale analysis. (E–H) Large-scale analysis. (A,E) Total locomotion distance traveled. C57BL/6J mice traveled the longest distance. (B,F) Count of vertical activity. C57BL/6N exhibited the lowest vertical activity. (C,G) Time spent in the center of the compartment. (D,H) Count of stereotypic behavior. Error bars indicate SEM.

Figure 4

Light-dark transition test of C57BL/6 substrains. (A–D) Regular scale analysis. (E–H) Large-scale analysis. (A,E) Distance traveled in the light and dark box. C57BL/6J mice traveled the longest distance. (B,F) Number of transitions between the light and dark box. C57BL/6C mice showed the least number of transitions. (C,G) Latency time before the first entry to the light box. C57BL/6C mice showed longer latency to enter the light box. (D,H) Time the mice stayed in the light box. C57BL/6C mice stayed less time in the light box. *p < 0.05, **p < 0.005, ***p < 0.0001. Error bars indicate SEM.

Figure 5

Elevated plus maze test of C57BL/6 substrains. (A–D) Regular scale analysis. (E–H) Large-scale analysis. (A,F) Total distance traveled. C57BL/6J mice traveled the longest distance in the large-scale analysis. (B,G) Number of entries into the center crossing between the open and closed arms. C57BL/6J showed the largest number of total arm entries in the large-scale analysis. (C,H) Percent number of entries into the open arms. C57BL/6J exhibited the highest percentage of entries into open arms. (D,I) Percent time spent on the open arms. C57BL/6J spent the longest time in open arms. (E,J) Percent time spent on the center of the maze. *p < 0.05, **p < 0.001, ***p < 0.0001. Error bars indicate SEM.

Figure 6

Social interaction test of C57BL/6 substrains. (A–D) Regular scale analysis. (E–H) Large-scale analysis. (A,E) Total distance traveled. (B,F) Number of contacts. (C,G) Total duration of contacts. (D,H) Mean duration per contacts. *p < 0.05, **p < 0.01, ***p < 0.0001. Error bars indicate SEM.

Figure 7

Startle response/prepulse inhibition test of C57BL/6 substrains. (A,B) Regular scale analysis. (C,D) Large-scale analysis. (A,C) Acoustic startle response for the 110 and 120 dB startle stimulus. C57BL/6N showed the lowest startle amplitude. (B,D) Prepulse inhibition for the 74 and 78 dB prepulse sound level. C57BL/6N showed the highest prepulse inhibition. *p < 0.05, **p < 0.01, ***p < 0.0001. Error bars indicate SEM.

Figure 8

Porsolt swim test of C57BL/6 substrains. (A,B) Regular scale analysis. (C,D) Large-scale analysis. (A,C) Immobility time (%) in each block for trial 1 and trial 2. (B,D) Total distance traveled in each block for trial 1 and trial 2. Error bars indicate SEM.

Figure 9

Spatial working memory version of eight-arm radial maze test of C57BL/6 substrains. (A–C) Regular scale analysis. (D–F) Large-scale analysis. (A,D) Number of different arms chosen within the first eight choices. (B,E) Number of revisiting errors. (C,F) Latency. C57BL/6J showed the shortest latency to take all pellets. Error bars indicate SEM.