Strain and sex Differences in Anxiety-Like and Social Behaviors in C57Bl/6J and BALB/cJ Mice

Institute of Brain and Behavioral Sciences, Shaanxi Normal University, Xi'an 710062, China.
Experimental Animals (Impact Factor: 0.97). 01/2011; 60(2):111-23. DOI: 10.1538/expanim.60.111
Source: PubMed


Mood disorders are more frequent in women than men, however, the majority of research has focused on male rodents as animal models. We used a variety of common behavioral tests to look for differences in anxiety-like and social behaviors between and within C57BL/6J and BALB/cJ mice. Our results show that female C57BL/6J mice exhibited lower levels of anxiety-like behavior and higher levels of activity than female BALB/cJ during the open field and elevated plus maze tests. Principal component analysis generated more factors in the behavioral variables of males than females. In the open field, a sex difference was also found and factor 1 emerged as anxiety in males, and motor activity in females. While C57BL/6J mice were found to have higher levels of social exploration and social contacts, differences were found between the sexes (females were more social) in both strains for this measure and also for anxiety-like behaviors. When interacting with animals of the same sex, levels of sniffing body and huddling in both male and female C57BL/6J mice were higher than those in male and female BALB/cJ mice. However, in the between-sex interactions, male C57BL/6J mice sniffed the stimulus mouse less, and female C57BL/6J mice sniffed the stimulus more compared to BALB/cJ mice. This study provides important behavioral phenotypes and confirms the multidimensional behavioral structure of two widely used mice strains.

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Available from: Enqi Liu, Oct 05, 2015
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    • "Importantly, considering the significantly decreased vHIP LTP with continued HFD feeding, it is apparent that HFD compromises the normal functioning of this hippocampal sub-structure. One likely implication of the present results is that, potentially, HFD is among the contributing factors for the recognized increased female vulnerability to mood disorders (An et al., 2011). "
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    ABSTRACT: Mounting experimental evidence, predominantly from male rodents, demonstrates that high-fat diet (HFD) consumption and ensuing obesity are detrimental to the brain. To shed additional light on the neurological consequences of HFD consumption in female rodents and to determine the relatively early impact of HFD in the likely continuum of neurological dysfunction in the context of chronic HFD intake, this study investigated effects of HFD feeding for up to 12 weeks on selected behavioral, neurochemical, and electrophysiological parameters in adult female C57BL/6 mice; particular focus was placed on the ventral hippocampus (vHIP). Selected locomotor, emotional and cognitive functions were evaluated using behavioral tests after 5 weeks on HFD or control (low-fat diet) diets. One week later, mice were sacrificed and brain regional neurochemical (monoamine) analysis was performed. Behaviorally naïve mice were maintained on their respective diets for additional 5-6 weeks at which time synaptic plasticity was determined in ex vivo slices from the vHIP. HFD-fed female mice exhibited increased: (i) locomotor activity in the open field testing, (ii) mean turn time on the pole test, (iii) swimming time in the forced swim test, and (iv) number of marbles buried in the marble burying test. In contrast, the novel object recognition memory was unaffected. Mice on HFD also had decreased norepinephrine and dopamine turnover, respectively, in the prefrontal cortex and the vHIP. HFD consumption for a total of 11-12 weeks altered vHIP synaptic plasticity, evidenced by significant reductions in the paired-pulse ratio and long-term potentiation (LTP) magnitude. In summary, in female mice, HFD intake for several weeks induced multiple behavioral alterations of mainly anxiety-like nature and impaired monoamine pathways in a brain-region specific manner, suggesting that that in the female, certain behavioral domains (anxiety) and associated brain regions, i.e., the vHIP, are preferentially targeted by HFD. Copyright © 2015. Published by Elsevier Ltd.
    Neuroscience 04/2015; 297. DOI:10.1016/j.neuroscience.2015.03.068 · 3.36 Impact Factor
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    • "The possibility of sex accounting for the different findings across studies is especially relevant given that the majority of studies used male rodents whereas females were used here. Indeed, sex differences using the OF and EPM have been described, with female rodents generally displaying less anxiety-like behaviors and increased exploration than their male counterparts (An et al., 2011; Frye et al., 2000; Johnston and File, 1991; Rodgers and Cole, 1993; Zimmerberg and Farley, 1993). Both SNI and sham rats showed significant decreases in the number of grooming bouts in the OF at 4 weeks post-injury versus baseline, further indicating that by the second time point our female rats had habituated to the OF and were not showing signs of stress or anxiogenic behaviors. "
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    ABSTRACT: Peripheral neuropathy often manifests clinically with symptoms of mechanical and cold allodynia. However, the neuroplastic changes associated with peripheral neuropathic pain and the onset and progression of allodynic symptoms remain unclear. Here, we used a chronic neuropathic pain model (spared nerve injury; SNI) to examine functional and metabolic brain changes associated with the development and maintenance of mechanical and cold hypersensitivity, the latter which we assessed both behaviorally and during a novel acetone application paradigm using functional MRI (fMRI). Female Sprague–Dawley rats underwent SNI (n = 7) or sham (n = 5) surgery to the left hindpaw. Rats were anesthetized and scanned using a 7 T MRI scanner 1 week prior to (pre-injury) and 4 (early/subchronic) and 20 weeks (late/chronic) post-injury. Functional scans were acquired during acetone application to the left hindpaw. 1H magnetic resonance spectroscopy was also performed to assess SNI-induced metabolic changes in the anterior cingulate cortex (ACC) pre- and 4 weeks post-injury. Mechanical and cold sensitivity, as well as anxiety-like behaviors, were assessed 2 weeks pre-injury, and 2, 5, 9, 14, and 19 weeks post-injury. Stimulus-evoked brain responses (acetone application to the left hindpaw) were analyzed across the pre- and post-injury time points. In response to acetone application during fMRI, SNI rats showed widespread and functionally diverse changes within pain-related brain regions including somatosensory and cingulate cortices and subcortically within the thalamus and the periaqueductal gray. These functional brain changes temporally coincided with early and sustained increases in both mechanical and cold sensitivity. SNI rats also showed increased glutamate within the ACC that correlated with behavioral measures of cold hypersensitivity. Together, our findings suggest that extensive functional reorganization within pain-related brain regions may underlie the development and chronification of allodynic-like behaviors.
    NeuroImage 02/2015; 107:333-344. DOI:10.1016/j.neuroimage.2014.12.024 · 6.36 Impact Factor
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    • "In addition, the strong diurnal changes of corticosterone concentrations reach the maximal values in the first third of the dark phase, i.e. the period used for faeces collection of this study (Touma et al. 2004). We can also not exclude a strain-specific impact on the results of corticosterone metabolites, although C57BL/6J mice are known for a lower sensitivity to subchronic mild stress and for a lower level of anxiety-like behaviour than other inbred strains (Ducottet and Belzung 2005; An et al. 2011). The histology of reproductive organs showed no lesions on the vaginal mucosa of either juvenile or adult females. "
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    ABSTRACT: Superovulation of mice is routinely used to increase the number of obtainable ova per female. Because of the better outcome, prepubescent females are preferentially used. Here, we provide results of the impact of superovulation and mating on the wellbeing of juvenile compared with adult C57BL/6N mice. Two groups of mice (3-4 weeks vs 7-8 weeks old) were superovulated and mated. Observation of mating behaviour showed that reluctant adult females tended to fight the male's approach, whereas juveniles preferred to take flight. Faeces were collected daily for the analysis of stress hormones. There was no difference in the levels of glucocorticoid metabolites either between age groups or between treated animals and their controls. Histology after mating revealed intact vaginal mucosa without any detectable lesions in all animals regardless of age. In contrast to adults, almost all juveniles were synchronised in oestrus and produced significantly more ova. Taken together, our results reveal no increased welfare problem from using juvenile mice for superovulation and mating. Considering the higher yield of fertilisable oocytes and zygotes, it is advisable to use C57BL/6N prepubescent mice in order to reduce the number of donor females required.
    Reproduction Fertility and Development 12/2014; DOI:10.1071/RD14372 · 2.40 Impact Factor
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