The open field test as a method for ethology in Kunming mice: test-retest reliability

Abstract

Objective To explore the test-retest reliability of the open field test,as a method for ethology in Kunming mice. Methods The behavior of adult male Kunming mice in the open field test was recorded twice,once for five minutes, with a one-week inter-trial interval. The following parameters were evaluated:number of central squares; number of peripheral squares; percent of central squares; number of horizontal squares; number of rearings; total score; and number of fecal boli. Subsequently,the intraclass correlation coefficient (ICC) and the agreement index (Kappa) were calculated for each of these parameters. Results Both ICC and Kappa for total score( ICC =0.902, P＜0.01; Kappa =0.680, P＜0.01; r=0.815, P＜0.01 ) showed a good reliability and correlation between the test trials. Only ICC for number of central squares ( ICC = 0. 578, P ＜ 0.01 ), number of peripheral squares( ICC =0.615, P＜0.01 ) ,percent of central squares(ICC=0.523, P＜0.01) ,number of horizontal squares( ICC = 0. 607, P ＜ 0.01 ) and number of rearings ( ICC = 0. 606, P ＜ 0.01 ) indicated a fair reliability between the test trials. Neither ICC nor Kappa for number of fecal boli displayed a significant reliability between the test trials. The difference of these parameters between test and retest, such as number of peripheral squares( t =3.01, P＜0.01 ),number of horizontal squares( t = 3.34, P ＜ 0.01 ) and total score( t = 7.86, P ＜ 0.01 ) were significant. Conclusion The parameter,total score for Kunming mice in the open field test,is found to be stable over time, and indicates a good reliability with a one-week inter-trial interval. Key words: Open field test; State anxiety; Ethology; Test-retest reliability; Kunming Mice