Effects of Housing Conditions on Anxiety-Like Behavior

Abstract

Pain is modulated by multidimensional components. It is no longer adequate for us only looking into nociceptive component. One factor that plays a critical role in pain modulation is anxiety. Previous clinical studies have showed that affective pain is strongly associated with anxiety. The current study was to investigate the effects of cage complexity and social interaction on anxiety level. Four housing conditions as treatment groups were arranged, 1) three rats were housed in the same cage with toys (S/E), 2) three rats were housed in the same without toys (S/NE), 3) one rat was housed individually with toys (NS/E), 4) one rat was housed individually without toys (NS/NE). The subjects' anxiety level were assessed by open field test and elevated plus-maze test. The results showed that there were no statistically significant differences among the treatment groups, but there was a clear consistent trend demonstrated both in open field test and elevated plus-maze test that following the baseline data collection, after the rats (NS/E,NS/NE) were housed individually for a week, the anxiogenic profile increased that was indicated by the decrease in the time spent in the center square in open field apparatus and the time spent in open arms in elevated plus-maze test. And also the locomotive activities decreased in the number of time of exploring the novel object and the number of times of rearing events in open field apparatus. Isolation housing condition has been considered as a stress to organism. We speculated that isolation condition induced deregulation of HPA axis, it led to alteration of anxiety level.