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Sex-dependent effects of an early life treatment in rats that increases maternal care: vulnerability or resilience?

Fuentes S, Daviu N, Gagliano H, Garrido P, Zelena D, Monasterio N, Armario A, Nadal R - Front Behav Neurosci (2014)

Bottom Line: ELS decreased pup body weight and increased the care of the biological mother; however, the "substitute" mother did not exhibit overt maltreatment.A mixture of "detrimental" and "beneficial" effects was shown.The enhancement in maternal care may "buffer" the effects of ELS in a context-dependent manner.

View Article: PubMed Central - PubMed

Affiliation: Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain.

ABSTRACT
Early life stress (ELS) in rodents has profound long-term effects that are partially mediated by changes in maternal care. ELS not only induces "detrimental" effects in adulthood, increasing psychopathology, but also promotes resilience to further stressors. In Long-Evans rats, we evaluated a combination of two procedures as a model of ELS: restriction of bedding during the first post-natal days and exposure to a "substitute" mother. The maternal care of biological and "substitute" mothers was measured. The male and female offspring were evaluated during adulthood in several contexts. Anxiety was measured by the elevated plus-maze (EPM), acoustic startle response (ASR) and forced swim test (FST). In other group of animals, novelty-seeking was measured (activity in an inescapable novel environment, preference for novel environments and exploration of novel objects). Plasmatic ACTH and corticosterone in basal conditions and in response to stress were also measured. Cognitive impulsivity was assessed by a delay-discounting paradigm, and impulsive action, attention and compulsive-like behavior by a five choice serial reaction time task (5CSRTT). ELS decreased pup body weight and increased the care of the biological mother; however, the "substitute" mother did not exhibit overt maltreatment. A mixture of "detrimental" and "beneficial" effects was shown. In the 5CSRTT, attention was impaired in both genders, and in females, ELS increased compulsive-like behavior. Novel object exploration was only increased by ELS in males, but the preference for novel spaces decreased in both genders. Baseline anxiety (EPM and ASR) and recognition memory were not affected. Unexpectedly, ELS decreased the ACTH response to novelty and swim stress and increased active coping in the FST in both genders. Cognitive impulsivity was decreased only in females, but impulsive action was not affected. The enhancement in maternal care may "buffer" the effects of ELS in a context-dependent manner.

No MeSH data available.


Related in: MedlinePlus

ACTH (pg/ml) and corticosterone (ng/ml) levels (X ± s.e.m.) in response to swim stress (A,C) and novelty stress (B,D), in males and females for control (CTR) and early-life stress (ELS) rats. *p < 0.05 vs. CTR, +++p < 0.001 vs. males. For ACTH, the ELS, GENDER, and STRESSOR effects were statistically significant, but not the interaction. For corticosterone, only GENDER was statistically significant.
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Figure 9: ACTH (pg/ml) and corticosterone (ng/ml) levels (X ± s.e.m.) in response to swim stress (A,C) and novelty stress (B,D), in males and females for control (CTR) and early-life stress (ELS) rats. *p < 0.05 vs. CTR, +++p < 0.001 vs. males. For ACTH, the ELS, GENDER, and STRESSOR effects were statistically significant, but not the interaction. For corticosterone, only GENDER was statistically significant.

Mentions: The basal levels of ACTH and corticosterone were not affected by ELS (see Table 3D) and were higher in females than males [for ACTH: GENDER: F(1, 42) = 6.39, p < 0.05; for corticosterone: GENDER: F(1, 42) = 50.08, p < 0.001; ELS and GENDER × ELS were NS in both cases]. As the HPA axis reactivity to stress was analyzed after a novel environment (preference for novelty test) and after the FST, STRESSOR was included in the statistical analysis as a factor. The ACTH levels in response to the novel environment and to the FST were reduced by ELS (Figures 9A,B). In these tests, statistical analysis showed that: (1) ELS decreased the endocrine response to the tests in both males and females [ELS:F(1, 90) = 6.07, p < 0.05]; (2) females had higher ACTH levels than males in response to the tests [GENDER: F(1, 90) = 27.83, p < 0.001); and (3) ACTH levels in response to the FST were higher than in response to the novel environment [STRESSOR: F(1, 90) = 73.26, p < 0.001]; however, the interactions between factors were NS. Regarding the corticosterone response to the tests (Figures 9C,D), GENDER was the only statistically significant factor [F(1, 90) = 985.81, p < 0.001], indicating that females had higher corticosterone levels than males regardless of the stressor.


Sex-dependent effects of an early life treatment in rats that increases maternal care: vulnerability or resilience?

Fuentes S, Daviu N, Gagliano H, Garrido P, Zelena D, Monasterio N, Armario A, Nadal R - Front Behav Neurosci (2014)

ACTH (pg/ml) and corticosterone (ng/ml) levels (X ± s.e.m.) in response to swim stress (A,C) and novelty stress (B,D), in males and females for control (CTR) and early-life stress (ELS) rats. *p < 0.05 vs. CTR, +++p < 0.001 vs. males. For ACTH, the ELS, GENDER, and STRESSOR effects were statistically significant, but not the interaction. For corticosterone, only GENDER was statistically significant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3934416&req=5

Figure 9: ACTH (pg/ml) and corticosterone (ng/ml) levels (X ± s.e.m.) in response to swim stress (A,C) and novelty stress (B,D), in males and females for control (CTR) and early-life stress (ELS) rats. *p < 0.05 vs. CTR, +++p < 0.001 vs. males. For ACTH, the ELS, GENDER, and STRESSOR effects were statistically significant, but not the interaction. For corticosterone, only GENDER was statistically significant.
Mentions: The basal levels of ACTH and corticosterone were not affected by ELS (see Table 3D) and were higher in females than males [for ACTH: GENDER: F(1, 42) = 6.39, p < 0.05; for corticosterone: GENDER: F(1, 42) = 50.08, p < 0.001; ELS and GENDER × ELS were NS in both cases]. As the HPA axis reactivity to stress was analyzed after a novel environment (preference for novelty test) and after the FST, STRESSOR was included in the statistical analysis as a factor. The ACTH levels in response to the novel environment and to the FST were reduced by ELS (Figures 9A,B). In these tests, statistical analysis showed that: (1) ELS decreased the endocrine response to the tests in both males and females [ELS:F(1, 90) = 6.07, p < 0.05]; (2) females had higher ACTH levels than males in response to the tests [GENDER: F(1, 90) = 27.83, p < 0.001); and (3) ACTH levels in response to the FST were higher than in response to the novel environment [STRESSOR: F(1, 90) = 73.26, p < 0.001]; however, the interactions between factors were NS. Regarding the corticosterone response to the tests (Figures 9C,D), GENDER was the only statistically significant factor [F(1, 90) = 985.81, p < 0.001], indicating that females had higher corticosterone levels than males regardless of the stressor.

Bottom Line: ELS decreased pup body weight and increased the care of the biological mother; however, the "substitute" mother did not exhibit overt maltreatment.A mixture of "detrimental" and "beneficial" effects was shown.The enhancement in maternal care may "buffer" the effects of ELS in a context-dependent manner.

View Article: PubMed Central - PubMed

Affiliation: Institut de Neurociències, Universitat Autònoma de Barcelona Barcelona, Spain.

ABSTRACT
Early life stress (ELS) in rodents has profound long-term effects that are partially mediated by changes in maternal care. ELS not only induces "detrimental" effects in adulthood, increasing psychopathology, but also promotes resilience to further stressors. In Long-Evans rats, we evaluated a combination of two procedures as a model of ELS: restriction of bedding during the first post-natal days and exposure to a "substitute" mother. The maternal care of biological and "substitute" mothers was measured. The male and female offspring were evaluated during adulthood in several contexts. Anxiety was measured by the elevated plus-maze (EPM), acoustic startle response (ASR) and forced swim test (FST). In other group of animals, novelty-seeking was measured (activity in an inescapable novel environment, preference for novel environments and exploration of novel objects). Plasmatic ACTH and corticosterone in basal conditions and in response to stress were also measured. Cognitive impulsivity was assessed by a delay-discounting paradigm, and impulsive action, attention and compulsive-like behavior by a five choice serial reaction time task (5CSRTT). ELS decreased pup body weight and increased the care of the biological mother; however, the "substitute" mother did not exhibit overt maltreatment. A mixture of "detrimental" and "beneficial" effects was shown. In the 5CSRTT, attention was impaired in both genders, and in females, ELS increased compulsive-like behavior. Novel object exploration was only increased by ELS in males, but the preference for novel spaces decreased in both genders. Baseline anxiety (EPM and ASR) and recognition memory were not affected. Unexpectedly, ELS decreased the ACTH response to novelty and swim stress and increased active coping in the FST in both genders. Cognitive impulsivity was decreased only in females, but impulsive action was not affected. The enhancement in maternal care may "buffer" the effects of ELS in a context-dependent manner.

No MeSH data available.


Related in: MedlinePlus