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Influence of daily social stimulation on behavioral and physiological outcomes in an animal model of PTSD.

Seetharaman S, Fleshner M, Park CR, Diamond DM - Brain Behav (2016)

Bottom Line: We also found that social stimulation and psychosocial stress produced equivalent outcomes in some measures, including adrenal and heart hypertrophy, thymus atrophy, and a reduction in poststress corticosterone levels.It is notable that daily social stimulation normalized a subset, but not all, of the PTSD-like effects.We discuss our findings in the context of the literature demonstrating that social stimulation can counteract the adverse effects of traumatic stress on behavioral and physiological measures, as well as to produce its own stress-like outcomes.

View Article: PubMed Central - PubMed

Affiliation: Department of PsychologySt. Ambrose UniversityDavenportIowa52803; Center for Preclinical and Clinical Research on PTSDUniversity of South FloridaTampaFlorida33620.

ABSTRACT

Introduction: We have shown in previous work that acute episodes of predator exposure occurring in the context of chronic social instability produced PTSD-like sequelae in rats. Our animal model of PTSD contained two components: (1) acute trauma, immobilization of rats in close proximity to a cat twice in 10 days, and (2) chronic social instability, 31 days of randomized housing of cage cohorts. Here we tested the hypothesis that daily social stimulation would block the development of the PTSD-like sequelae.

Methods: Beginning 24 h after the first cat exposure, adult male rats were given our established PTSD model, alone or in conjunction with daily social stimulation, in which all rats within a group interacted in a large apparatus for 2 h each day for the final 30 days of the PTSD regimen. All behavioral, for example, anxiety, memory, startle testing, and physiological assessments, for example, body growth, organ weights, and corticosterone levels, took place following completion of the psychosocial stress period.

Results: Daily social stimulation blocked the expression of a subset of PTSD-like effects, including predator-based cued fear conditioning, enhanced startle response, heightened anxiety on the elevated plus maze and the stress-induced suppression of growth rate. We also found that social stimulation and psychosocial stress produced equivalent outcomes in some measures, including adrenal and heart hypertrophy, thymus atrophy, and a reduction in poststress corticosterone levels.

Conclusions: Daily exposure of rats to a highly social environment blocked the development of a subset of trauma-induced sequelae, particularly fear-related outcomes. It is notable that daily social stimulation normalized a subset, but not all, of the PTSD-like effects. We discuss our findings in the context of the literature demonstrating that social stimulation can counteract the adverse effects of traumatic stress on behavioral and physiological measures, as well as to produce its own stress-like outcomes.

No MeSH data available.


Related in: MedlinePlus

Assessment of contextual and cued predator‐based fear conditioning. There were no significant between‐group differences in immobility (upper left) or fecal boli production (upper right) upon re‐exposure of the rats to the cat‐associated context. There were significant between‐group differences in immobility (lower left) and fecal boli production (lower right) in response to the tone. Specifically, the No Social/Stress group showed a significant elevation in immobility relative to No Social/No Stress controls. This increase in immobility was prevented with social stimulation, indicated by significantly lower immobility levels in the Social/No Stress and Social/Stress groups. In a similar pattern, boli production was reduced with social stimulation relative to the No Social/Stress group. Note that both Social groups exhibited greater boli production than the No Social/No Stress group, and the No Social/Stress group produced the greatest number of boli of all groups (lower right). Data are presented as mean ± SEM. *P < 0.05 compared to all other groups; βP < 0.05 relative to the no social groups.
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brb3458-fig-0002: Assessment of contextual and cued predator‐based fear conditioning. There were no significant between‐group differences in immobility (upper left) or fecal boli production (upper right) upon re‐exposure of the rats to the cat‐associated context. There were significant between‐group differences in immobility (lower left) and fecal boli production (lower right) in response to the tone. Specifically, the No Social/Stress group showed a significant elevation in immobility relative to No Social/No Stress controls. This increase in immobility was prevented with social stimulation, indicated by significantly lower immobility levels in the Social/No Stress and Social/Stress groups. In a similar pattern, boli production was reduced with social stimulation relative to the No Social/Stress group. Note that both Social groups exhibited greater boli production than the No Social/No Stress group, and the No Social/Stress group produced the greatest number of boli of all groups (lower right). Data are presented as mean ± SEM. *P < 0.05 compared to all other groups; βP < 0.05 relative to the no social groups.

Mentions: There were no significant between‐group differences in immobility to the context temporally paired with the two cat exposures (Fig. 2, upper left). Similarly, there were no significant main effects of either Stress or Social stimulation, and there was an absence of a Stress × Social stimulation interaction in the fecal boli analysis during contextual fear testing (Fig. 2, upper right).


Influence of daily social stimulation on behavioral and physiological outcomes in an animal model of PTSD.

Seetharaman S, Fleshner M, Park CR, Diamond DM - Brain Behav (2016)

Assessment of contextual and cued predator‐based fear conditioning. There were no significant between‐group differences in immobility (upper left) or fecal boli production (upper right) upon re‐exposure of the rats to the cat‐associated context. There were significant between‐group differences in immobility (lower left) and fecal boli production (lower right) in response to the tone. Specifically, the No Social/Stress group showed a significant elevation in immobility relative to No Social/No Stress controls. This increase in immobility was prevented with social stimulation, indicated by significantly lower immobility levels in the Social/No Stress and Social/Stress groups. In a similar pattern, boli production was reduced with social stimulation relative to the No Social/Stress group. Note that both Social groups exhibited greater boli production than the No Social/No Stress group, and the No Social/Stress group produced the greatest number of boli of all groups (lower right). Data are presented as mean ± SEM. *P < 0.05 compared to all other groups; βP < 0.05 relative to the no social groups.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4834360&req=5

brb3458-fig-0002: Assessment of contextual and cued predator‐based fear conditioning. There were no significant between‐group differences in immobility (upper left) or fecal boli production (upper right) upon re‐exposure of the rats to the cat‐associated context. There were significant between‐group differences in immobility (lower left) and fecal boli production (lower right) in response to the tone. Specifically, the No Social/Stress group showed a significant elevation in immobility relative to No Social/No Stress controls. This increase in immobility was prevented with social stimulation, indicated by significantly lower immobility levels in the Social/No Stress and Social/Stress groups. In a similar pattern, boli production was reduced with social stimulation relative to the No Social/Stress group. Note that both Social groups exhibited greater boli production than the No Social/No Stress group, and the No Social/Stress group produced the greatest number of boli of all groups (lower right). Data are presented as mean ± SEM. *P < 0.05 compared to all other groups; βP < 0.05 relative to the no social groups.
Mentions: There were no significant between‐group differences in immobility to the context temporally paired with the two cat exposures (Fig. 2, upper left). Similarly, there were no significant main effects of either Stress or Social stimulation, and there was an absence of a Stress × Social stimulation interaction in the fecal boli analysis during contextual fear testing (Fig. 2, upper right).

Bottom Line: We also found that social stimulation and psychosocial stress produced equivalent outcomes in some measures, including adrenal and heart hypertrophy, thymus atrophy, and a reduction in poststress corticosterone levels.It is notable that daily social stimulation normalized a subset, but not all, of the PTSD-like effects.We discuss our findings in the context of the literature demonstrating that social stimulation can counteract the adverse effects of traumatic stress on behavioral and physiological measures, as well as to produce its own stress-like outcomes.

View Article: PubMed Central - PubMed

Affiliation: Department of PsychologySt. Ambrose UniversityDavenportIowa52803; Center for Preclinical and Clinical Research on PTSDUniversity of South FloridaTampaFlorida33620.

ABSTRACT

Introduction: We have shown in previous work that acute episodes of predator exposure occurring in the context of chronic social instability produced PTSD-like sequelae in rats. Our animal model of PTSD contained two components: (1) acute trauma, immobilization of rats in close proximity to a cat twice in 10 days, and (2) chronic social instability, 31 days of randomized housing of cage cohorts. Here we tested the hypothesis that daily social stimulation would block the development of the PTSD-like sequelae.

Methods: Beginning 24 h after the first cat exposure, adult male rats were given our established PTSD model, alone or in conjunction with daily social stimulation, in which all rats within a group interacted in a large apparatus for 2 h each day for the final 30 days of the PTSD regimen. All behavioral, for example, anxiety, memory, startle testing, and physiological assessments, for example, body growth, organ weights, and corticosterone levels, took place following completion of the psychosocial stress period.

Results: Daily social stimulation blocked the expression of a subset of PTSD-like effects, including predator-based cued fear conditioning, enhanced startle response, heightened anxiety on the elevated plus maze and the stress-induced suppression of growth rate. We also found that social stimulation and psychosocial stress produced equivalent outcomes in some measures, including adrenal and heart hypertrophy, thymus atrophy, and a reduction in poststress corticosterone levels.

Conclusions: Daily exposure of rats to a highly social environment blocked the development of a subset of trauma-induced sequelae, particularly fear-related outcomes. It is notable that daily social stimulation normalized a subset, but not all, of the PTSD-like effects. We discuss our findings in the context of the literature demonstrating that social stimulation can counteract the adverse effects of traumatic stress on behavioral and physiological measures, as well as to produce its own stress-like outcomes.

No MeSH data available.


Related in: MedlinePlus