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Social isolation-induced aggression potentiates anxiety and depressive-like behavior in male mice subjected to unpredictable chronic mild stress.

Ma XC, Jiang D, Jiang WH, Wang F, Jia M, Wu J, Hashimoto K, Dang YH, Gao CG - PLoS ONE (2011)

Bottom Line: Accumulating epidemiological evidence shows that life event stressors are major vulnerability factors for psychiatric diseases such as major depression.It is also well known that social isolation in male mice results in aggressive behavior.In the light/black box test, Groups II and III animals spent significantly less time in the light box compared to Group I animals.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xian, China.

ABSTRACT

Background: Accumulating epidemiological evidence shows that life event stressors are major vulnerability factors for psychiatric diseases such as major depression. It is also well known that social isolation in male mice results in aggressive behavior. However, it is not known how social isolation-induced aggression affects anxiety and depressive-like behavior in isolated male mice subjected to unpredictable chronic mild stress (CMS), an animal model of depression.

Methodology/principal findings: C57/B6 male mice were divided into 3 groups; non-stressed controls, in Group I; isolated mice subjected to the CMS protocol in Group II and aggression by physical contact in socially isolated mice subjected to the CMS protocol in Group III. In the sucrose intake test, ingestion of a 1% sucrose solution by mice in Groups II and III was significantly lower than in Group I. Furthermore, intake of this solution in Group III mice was significantly lower than in Group II mice. In the open field test, mice in Group III, showed reduced locomotor activity and reduced entry and retention time in the central zone, compared to Groups I and II mice. Moreover, the distances moved in 1 hour by Group III mice did not differ between night and morning. In the light/black box test, Groups II and III animals spent significantly less time in the light box compared to Group I animals. In the tail suspension test (TST) and forced swimming test (FST), the immobility times of Group II and Group III mice were significantly longer than in Group I mice. In addition, immobility times in the FST were significantly longer in Group III than in Group II mice.

Conclusions/significance: These findings show that social isolation-induced aggression could potentiate anxiety and depressive-like behaviors in isolated male mice subjected to CMS.

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Related in: MedlinePlus

Light/dark box test.(A) Number of entries into the light box. (B) Retention time in the light box. The number of entries into the light box and the retention time in the light box for Groups II and III mice were significantly lower than for Group I mice. Values represent the mean ± SEM (n = 26 for Group I, n = 27 for Group II, n = 27 for Group III). **p<0.01, ***p<0.001.
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pone-0020955-g005: Light/dark box test.(A) Number of entries into the light box. (B) Retention time in the light box. The number of entries into the light box and the retention time in the light box for Groups II and III mice were significantly lower than for Group I mice. Values represent the mean ± SEM (n = 26 for Group I, n = 27 for Group II, n = 27 for Group III). **p<0.01, ***p<0.001.

Mentions: In the light/dark box test, one-way ANOVA analysis revealed that the number of light-dark box transitions in the three groups was significantly different (F [2,77] = 14.35, p<0.001). Post hoc Fisher's PLSD test showed that the number of transitions by mice in the two CMS model groups was significantly lower (p<0.001 for Group II vs. Group I, p<0.001 for Group III vs. Group I) than in Group I mice (Fig. 5A). Furthermore, one-way ANOVA analysis revealed that the retention time spent in the light box was significantly different (F [2,77] = 10.29, p<0.001) amongst the three groups. Post hoc Fisher's PLSD test showed that the time spent in the light box by Groups II and III animals was significantly lower (p = 0.002 for Group II vs. Group I, p<0.001 for Group III vs. Group I) than Group I animals (Fig. 5B). However, there was no statistical difference between Groups II and III. These results show that in the light/dark box test, mice in Groups II and III show anxiety-like behaviors.


Social isolation-induced aggression potentiates anxiety and depressive-like behavior in male mice subjected to unpredictable chronic mild stress.

Ma XC, Jiang D, Jiang WH, Wang F, Jia M, Wu J, Hashimoto K, Dang YH, Gao CG - PLoS ONE (2011)

Light/dark box test.(A) Number of entries into the light box. (B) Retention time in the light box. The number of entries into the light box and the retention time in the light box for Groups II and III mice were significantly lower than for Group I mice. Values represent the mean ± SEM (n = 26 for Group I, n = 27 for Group II, n = 27 for Group III). **p<0.01, ***p<0.001.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3117867&req=5

pone-0020955-g005: Light/dark box test.(A) Number of entries into the light box. (B) Retention time in the light box. The number of entries into the light box and the retention time in the light box for Groups II and III mice were significantly lower than for Group I mice. Values represent the mean ± SEM (n = 26 for Group I, n = 27 for Group II, n = 27 for Group III). **p<0.01, ***p<0.001.
Mentions: In the light/dark box test, one-way ANOVA analysis revealed that the number of light-dark box transitions in the three groups was significantly different (F [2,77] = 14.35, p<0.001). Post hoc Fisher's PLSD test showed that the number of transitions by mice in the two CMS model groups was significantly lower (p<0.001 for Group II vs. Group I, p<0.001 for Group III vs. Group I) than in Group I mice (Fig. 5A). Furthermore, one-way ANOVA analysis revealed that the retention time spent in the light box was significantly different (F [2,77] = 10.29, p<0.001) amongst the three groups. Post hoc Fisher's PLSD test showed that the time spent in the light box by Groups II and III animals was significantly lower (p = 0.002 for Group II vs. Group I, p<0.001 for Group III vs. Group I) than Group I animals (Fig. 5B). However, there was no statistical difference between Groups II and III. These results show that in the light/dark box test, mice in Groups II and III show anxiety-like behaviors.

Bottom Line: Accumulating epidemiological evidence shows that life event stressors are major vulnerability factors for psychiatric diseases such as major depression.It is also well known that social isolation in male mice results in aggressive behavior.In the light/black box test, Groups II and III animals spent significantly less time in the light box compared to Group I animals.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychiatry, First Affiliated Hospital of Medical College of Xi'an Jiaotong University, Xian, China.

ABSTRACT

Background: Accumulating epidemiological evidence shows that life event stressors are major vulnerability factors for psychiatric diseases such as major depression. It is also well known that social isolation in male mice results in aggressive behavior. However, it is not known how social isolation-induced aggression affects anxiety and depressive-like behavior in isolated male mice subjected to unpredictable chronic mild stress (CMS), an animal model of depression.

Methodology/principal findings: C57/B6 male mice were divided into 3 groups; non-stressed controls, in Group I; isolated mice subjected to the CMS protocol in Group II and aggression by physical contact in socially isolated mice subjected to the CMS protocol in Group III. In the sucrose intake test, ingestion of a 1% sucrose solution by mice in Groups II and III was significantly lower than in Group I. Furthermore, intake of this solution in Group III mice was significantly lower than in Group II mice. In the open field test, mice in Group III, showed reduced locomotor activity and reduced entry and retention time in the central zone, compared to Groups I and II mice. Moreover, the distances moved in 1 hour by Group III mice did not differ between night and morning. In the light/black box test, Groups II and III animals spent significantly less time in the light box compared to Group I animals. In the tail suspension test (TST) and forced swimming test (FST), the immobility times of Group II and Group III mice were significantly longer than in Group I mice. In addition, immobility times in the FST were significantly longer in Group III than in Group II mice.

Conclusions/significance: These findings show that social isolation-induced aggression could potentiate anxiety and depressive-like behaviors in isolated male mice subjected to CMS.

Show MeSH
Related in: MedlinePlus