RÉSUMÉ
Fecal samples are a non-invasive and relatively accessible matrix for investigating physiological processes in resident killer whale (Orcinus orca) populations. The high lipid content of the diet (primarily salmonids) leads to lower density fecal material and slower dispersion, facilitating sample collection. As fecal discharge is relatively infrequent and the volume of sample is variable, maximizing analytical options is an important consideration. Here we present an extraction methodology to measure hormones and lipid content from the same fecal aliquot. Lipid extractions are commonly conducted using chloroform and methanol from Folch or Bligh and Dyer (B&D), while alcohol is the primary solvent for hormone extraction. We evaluated the possibility of using the methanol layer from lipid extractions to assess fecal steroid hormone levels. Folch and B&D methanol residues were assayed form metabolites of progesterone (PMs) and corticosterone (GCs), and results were compared to aliquots extracted in 70 % ethanol. Hormone concentrations measured in the methanol layer from Folch and B&D extractions were 55 % to 79 % lower than concentrations in 70 % ethanol. We developed mathematical corrections, using linear regression models fitted to Folch or B&D methanol vs 70 % ethanol hormone concentrations (p < 0.01). Fecal concentrations of PMs and GCs from methanol extractions were biologically validated and are significantly higher in confirmed pregnant females compared to non-pregnant individuals (p < 0.05). This study demonstrates that lipid extraction protocols may be used for the analysis of multiple biomarkers, maximizing the use of small-volume samples.
Sujet(s)
Fèces , Orque épaulard , Animaux , Femelle , Corticostérone/métabolisme , Corticostérone/analyse , Fèces/composition chimique , Lipides/analyse , Progestérone/analyse , Progestérone/métabolisme , Orque épaulard/métabolismeRÉSUMÉ
Identifying reliable bioindicators of population status is a central goal of conservation physiology. Physiological stress measures are often used as metrics of individual health and can assist in managing endangered species if linked to fitness traits. We analysed feather corticosterone, a cumulative physiological stress metric, of individuals from historical, translocated, and source populations of an endangered endemic Hawaiian bird, the Laysan duck (Anas laysanensis). We hypothesized that feather corticosterone would reflect the improved reproduction and survival rates observed in populations translocated to Midway and Kure Atolls from Laysan Island. We also predicted less physiological stress in historical Laysan birds collected before ecological conditions deteriorated and the population bottleneck. All hypotheses were supported: we found lower feather corticosterone in the translocated populations and historical samples than in those from recent Laysan samples. This suggests that current Laysan birds are experiencing greater physiological stress than historical Laysan and recently translocated birds. Our initial analysis suggests that feather corticosterone may be an indicator of population status and could be used as a non-invasive physiological monitoring tool for this species with further validation. Furthermore, these preliminary results, combined with published demographic data, suggest that current Laysan conditions may not be optimal for this species.
Sujet(s)
Corticostérone , Canards , Espèce en voie de disparition , Plumes , Animaux , Corticostérone/analyse , Plumes/composition chimique , Hawaï , Stress physiologique , Conservation des ressources naturelles , Femelle , MâleRÉSUMÉ
Intrafacility transport of mice is an essential function for both laboratory and husbandry personnel. However, transport may induce a stress response that can alter research findings and negatively impact animal welfare. To determine minimally adverse intrafacility transport methods, in-cage noise and vibration exposure during transport on a variety of transport vehicles (hand carrying, stainless steel rack, flatbed cart, metal teacart, plastic teacart, and a cart with pneumatic wheels) were measured. Under-cage and in-cage padding was tested for its ability to decrease noise and vibration on each vehicle. Behavioral (open field test and elevated plus maze) and corticosterone responses of mice were then measured following transport on the most adverse (metal teacart) and least adverse (pneumatic cart) methods of multicage transport. Behavioral measures showed no difference between transported mice and untransported mice in both single- and group-housed settings. Plasma corticosterone was significantly elevated in mice transported on the metal teacart immediately following transport and continued to have elevated trends in circadian peaks during the 48h of sampling. The cart with pneumatic wheels was most effective at reducing noise and vibration, reflected in posttransport corticosterone readings that remained equivalent to those in untransported mice. This study demonstrates that mitigation of noise and vibration during cart transport may decrease the impact of transport on certain stress parameters in mice.
Sujet(s)
Bien-être animal , Corticostérone , Transports , Vibration , Animaux , Vibration/effets indésirables , Souris/physiologie , Corticostérone/sang , Corticostérone/analyse , Transports/méthodes , Mâle , Bruit/effets indésirables , Élevage/méthodes , Bruit des transports/effets indésirables , Comportement animal/physiologie , Souris de lignée C57BL/physiologie , Hébergement animalRÉSUMÉ
Avian embryos develop in an egg composition which reflects both maternal condition and the recent environment of their mother. In birds, yolk corticosterone (CORT) influences development by impacting pre- and postnatal growth, as well as nestling stress responses and development. One possible mechanism through which maternal CORT may affect offspring development is via changes to offspring DNA methylation. We sought to investigate this, for the first time in birds, by quantifying the impact of manipulations to maternal CORT on offspring DNA methylation. We non-invasively manipulated plasma CORT concentrations of egg-laying female zebra finches (Taeniopygia castanotis) with an acute dose of CORT administered around the time of ovulation and collected their eggs. We then assessed DNA methylation in the resulting embryonic tissue and in their associated vitelline membrane blood vessels, during early development (5 days after lay), using two established methods - liquid chromatography-mass spectrometry (LC-MS) and methylation-sensitive amplification fragment length polymorphism (MS-AFLP). LC-MS analysis showed that global DNA methylation was lower in embryos from CORT-treated mothers, compared to control embryos. In contrast, blood vessel DNA from eggs from CORT-treated mothers showed global methylation increases, compared to control samples. There was a higher proportion of global DNA methylation in the embryonic DNA of second clutches, compared to first clutches. Locus-specific analyses using MS-AFLP did not reveal a treatment effect. Our results indicate that an acute elevation of maternal CORT around ovulation impacts DNA methylation patterns in their offspring. This could provide a mechanistic understanding of how a mother's experience can affect her offspring's phenotype.
Sujet(s)
Corticostérone , Passeriformes , Animaux , Femelle , Corticostérone/pharmacologie , Corticostérone/analyse , Méthylation de l'ADN , Analyse de polymorphisme de longueur de fragments amplifiés , ADNRÉSUMÉ
Certain life stressors having enduring physiological and behavioral consequences, in part by eliciting dramatic signaling shifts in monoamine neurotransmitters. High monoamine levels can overwhelm selective transporters like the serotonin transporter. This is when polyspecific transporters like plasma membrane monoamine transporter (PMAT, Slc29a4) are hypothesized to contribute most to monoaminergic signaling regulation. Here, we employed two distinct counterbalanced stressors-fear conditioning and swim stress-in mice to systematically determine how reductions in PMAT function affect heterotypic stressor responsivity. We hypothesized that male heterozygotes would exhibit augmented stressor responses relative to female heterozygotes. Decreased PMAT function enhanced context fear expression, an effect unexpectedly obscured by a sham stress condition. Impaired cued fear extinction retention and enhanced context fear expression in males were conversely unmasked by a sham swim condition. Abrogated corticosterone levels in male heterozygotes that underwent swim stress after context fear conditioning did not map onto any measured behaviors. In sum, male heterozygous mouse fear behaviors proved malleable in response to preceding stressor or sham stress exposure. Combined, these data indicate that reduced male PMAT function elicits a form of stress-responsive plasticity. Future studies should assess how PMAT is differentially affected across sexes and identify downstream consequences of the stress-shifted corticosterone dynamics.
Sujet(s)
Peur , Animaux , Femelle , Mâle , Souris , Corticostérone/analyse , Extinction (psychologie) , Protéines de transport membranaire , Transduction du signalRÉSUMÉ
BACKGROUND: As a prey species, rabbits tend to hide their illnesses and injuries. Consequently, pet rabbit owners often do not notice that their pet may be suffering. METHODS: Data on the housing and health of 34 dwarf rabbits were collected from a total of 22 rabbit owners. A score from 0 (not stressed) to 3 (highly stressed) was assigned to each rabbit based on the owners' reports. Afterwards, the hair corticosterone concentration (HCC) of the rabbits was analysed as an indicator of long-term stress. RESULTS: The mean HCC of all rabbits was 1.54 ± 0.64 pg/mg. Animals with a stress score of 3 had a higher HCC (2.17 pg/mg) than those with a score of 0 (1.09 pg/mg) or 1 (1.44 pg/mg) (p < 0.05). HCC was not significantly affected by sex or age (p > 0.05). LIMITATION: Only a small number of rabbits were included in the study. Therefore, the findings need to be confirmed in a larger cohort of animals. CONCLUSION: HCC seems to be a promising stress marker in pet rabbits.
Sujet(s)
Corticostérone , Hébergement animal , Humains , Lapins , Animaux , Corticostérone/analyse , Poils/composition chimiqueRÉSUMÉ
The widespread use of phthalates (PAEs) has drawn increasing attention due to their endocrine disruption and reproductive toxicity, while the steroid metabolome is essential for follicular development. However, the mechanism by which PAE exposure affects ovarian reserve through the steroid metabolome remains unclear. This study recruited 264 childbearing-age women in Tianjin (China) from April 2019 to August 2020 in a cross-sectional design. Target metabolome analysis of 16 steroids was performed in follicular fluid (FF) to compare diminished ovarian reserve (DOR) against normal ovarian reserve (NOR) women and differential steroids were identified using binary logistic analyses. Further analysis of eleven PAE metabolites (mPAEs) in FF was conducted, and the retrieved oocyte number (RON) representing ovarian reserve was counted. Multiple linear regression and quantile-based g-computation (qgcomp) models were used to associate individual mPAEs and mPAE mixture with the DOR-related differential steroids in FF. Mediation analysis was used to discuss the mediating effect of DOR-related steroids on the association between mPAEs and RON. Androstenedione (A4), corticosterone (CORT), cortisol (COR) and cortisone were significantly down-regulated in FF from women with DOR. Nine mPAEs with detection frequencies greater than 60% and median concentrations of 0.02-4.86 ng/mL were incorporated into statistical models. Negative associations with COR and CORT were found for mono-ethyl phthalate (mEP), mono-(2-ethyl-5-oxohexyl) phthalate (mEOHP), and mono-2-ethylhexyl phthalate (mEHP). A positive association with cortisone was found for mEOHP, mEHP, monobutyl phthalate (mBP), and mono (2-isobutyl) phthalate (miBP). The qgcomp and mediation analyses revealed that mEP and mEOHP not only significantly contributed to the decline of COR and CORT in the mixed exposure but also indirectly reduced RON through the mediating effects of COR and CORT. In conclusion, PAE exposure may decrease ovarian reserve by downregulating COR and CORT.
Sujet(s)
Cortisone , Polluants environnementaux , Réserve ovarienne , Acides phtaliques , Femelle , Animaux , Liquide folliculaire/composition chimique , Cortisone/analyse , Cortisone/métabolisme , Études transversales , Acides phtaliques/toxicité , Acides phtaliques/métabolisme , Métabolome , Corticostérone/analyse , Exposition environnementale/analyse , Polluants environnementaux/toxicité , Polluants environnementaux/métabolismeRÉSUMÉ
Exposure to persistent organic pollutants (POPs), such as organochlorines (OCs) and polybrominated diphenyl ethers (PBDEs), is associated with adverse health effects in wildlife. Many POPs have been banned and consequently their environmental concentrations have declined. To assess both temporal trends of POPs and their detrimental impacts, raptors are extensively used as biomonitors due to their high food web position and high contaminant levels. White-tailed eagles (WTEs; Haliaeetus albicilla) in the Baltic ecosystem represent a sentinel species of environmental pollution, as they have suffered population declines due to reproductive failure caused by severe exposure to dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB) during the 1960s through 1980s. However, there is a lack of long-term studies that cover a wide range of environmental contaminants and their effects at the individual level. In this study, we used 135 pooled samples of shed body feathers collected in 1968-2012 from breeding WTE pairs in Sweden. Feathers constitute a temporal archive for substances incorporated into the feather during growth, including corticosterone, which is the primary avian glucocorticoid and a stress-associated hormone. Here, we analysed the WTE feather pools to investigate annual variations in feather corticosterone (fCORT), POPs (OCs and PBDEs), and stable carbon and nitrogen isotopes (SIs; dietary proxies). We examined whether the expected fluctuations in POPs affected fCORT (8-94 pg. mm-1) in the WTE pairs. Despite clear temporal declining trends in POP concentrations (p < 0.01), we found no significant associations between fCORT and POPs or SIs (p > 0.05 in all cases). Our results do not support fCORT as a relevant biomarker of contaminant-mediated effects in WTEs despite studying a highly contaminated population. However, although not detecting a relationship between fCORT, POP contamination and diet, fCORT represents a non-destructive and retrospective assessment of long-term stress physiology in wild raptors otherwise not readily available.
Sujet(s)
Aigles , Polluants environnementaux , Hydrocarbures chlorés , Polychlorobiphényles , Animaux , Corticostérone/analyse , Plumes , Études rétrospectives , Éthers de polyhalogénophényle/analyse , Écosystème , Surveillance de l'environnement/méthodes , Polychlorobiphényles/analyse , Polluants environnementaux/analyse , Hydrocarbures chlorés/analyseRÉSUMÉ
OBJECTIVES: To explore the associations of environmental endocrine disruptors on precocious puberty in girls. METHODS: This was a case-control study in which 30 girls with precocious puberty and 46 age- and race-matched prepubertal females were enrolled. The concentrations of 10 environment endocrine disruptors (bisphenol A, bisphenol B, butylparaben, propylparaben, ethvlparaben, methylparaben, mono-butyl phthalate, mono-2-ethylhexyl phthalate, monoethyl phthalate, and monomethyl phthalate) in urine and 10 steroid hormones (dihydrotestosterone, corticosterone, hydrocortisone, 11-deoxycortisol, 17α-hydroxy progesterone, 4-androstene-3,17-dione, estrone, deoxycorticosterone, pregnenolone, and dehydroepiandrosterone) in serum were detected with the liquid chromatography-mass spectrometry (LC-MS). RESULTS: According to the Mann-Whitney U test, urinary levels of bisphenol A, monobutyl phthalate, and monomethyl phthalate were significantly higher in the precocious group than in the prepubertal group, and blood levels of hydrocortisone, 11-deoxycortisol, corticosterone, deoxycorticosterone, and pregnenolone were significantly lower in the precocious group than in the prepubertal group (p<0.05, VIP>1). CONCLUSIONS: Our findings confirm the association between phthalate exposure and the incidence of precocious puberty in girls. Control and reduction of children exposure to phthalate esters should be considered as a health priority.
Sujet(s)
Perturbateurs endocriniens , Puberté précoce , Études cas-témoins , Enfant , Corticostérone/analyse , Cortodoxone/analyse , Désoxycorticostérone/analyse , Perturbateurs endocriniens/toxicité , Exposition environnementale/effets indésirables , Exposition environnementale/analyse , Femelle , Humains , Hydrocortisone , Prégnénolone/analyse , Puberté précoce/induit chimiquement , Puberté précoce/épidémiologieRÉSUMÉ
Early life stress (ELS) is associated with perturbed neural development and augmented vulnerability to mental health disorders, including addiction. How ELS changes the brain to increase addiction risk is poorly understood, and there are no therapies which target this ELS-induced vulnerability. ELS disrupts the oxytocin system, which can modulate addiction susceptibility, suggesting that targeting the oxytocin system may be therapeutic in this ELS-addiction comorbidity. Therefore, we determined whether adolescent oxytocin treatment after ELS could: (1) reduce vulnerability to anxiety, social deficits, and methamphetamine-taking and reinstatement; and (2) restore hypothalamic oxytocin and corticotropin-releasing factor expressing neurons and peripheral oxytocin and corticosterone levels. Long Evans pups underwent maternal separation (MS) for either 15 min or 360 min on postnatal days (PND) 1-21. During adolescence (PNDs 28-42), rats received a daily injection of either oxytocin or saline. In Experiment 1, adult rats were assessed using the elevated plus-maze, social interaction procedure, and methamphetamine self-administration procedure, including extinction, and cue-, methamphetamine- and yohimbine-induced reinstatement. In Experiment 2, plasma for enzyme immunoassays and brain tissue for immunofluorescence were collected from adult rats after acute stress exposure. Adolescent oxytocin treatment ameliorated ELS-induced anxiety and reduced methamphetamine- and yohimbine-induced reinstatement in both sexes, and suppressed methamphetamine intake and facilitated extinction in males only. Additionally, adolescent oxytocin treatment after ELS restored oxytocin-immunoreactive cells and stress-induced oxytocin levels in males, and attenuated stress-induced corticosterone levels in both sexes. Adolescent oxytocin treatment reverses some of the ELS effects on later-life psychopathology and vulnerability to addiction.
Sujet(s)
Troubles liés aux amphétamines , Métamfétamine , Ocytocine , Stress psychologique , Troubles liés aux amphétamines/traitement médicamenteux , Animaux , Corticostérone/analyse , Extinction (psychologie) , Femelle , Mâle , Séparation d'avec la mère , Métamfétamine/effets indésirables , Ocytocine/usage thérapeutique , Rats , Rat Long-Evans , Stress psychologique/traitement médicamenteux , Yohimbine/pharmacologieRÉSUMÉ
Complete Freund's adjuvant (CFA)-induced arthritis in rats is a common animal model for studying chronic inflammatory pain. However, modelling of the disease is associated with unnecessary pain and impaired animal wellbeing, particularly in the immediate post-induction phase. Few attempts have been made to counteract these adverse effects with analgesics. The present study investigated the effect of buprenorphine on animal welfare, pain-related behaviour and model-specific parameters during the disease progression in a rat model of CFA-induced monoarthritis. The aim was to reduce or eliminate unnecessary pain in this model, in order to improve animal welfare and to avoid suffering, without compromising the quality of the model. Twenty-four male Sprague Dawley rats were injected with 20 µl of CFA into the left tibio-tarsal joint to induce monoarthritis. Rats were treated with either buprenorphine or carprofen for 15 days during the disease development, and were compared to a saline-treated CFA-injected group or a negative control group. Measurements of welfare, pain-related behaviour and clinical model-specific parameters were collected. The study was terminated after 3 weeks, ending with a histopathologic analysis. Regardless of treatment, CFA-injected rats displayed mechanical hyperalgesia and developed severe histopathological changes associated with arthritis. However, no severe effects on general welfare were found at any time. Buprenorphine treatment reduced facial pain expression scores, improved mobility, stance and lameness scores and it did not supress the CFA-induced ankle swelling, contrary to carprofen. Although buprenorphine failed to demonstrate a robust analgesic effect on the mechanical hyperalgesia in this study, it did not interfere with the development of the intended pathology.
Sujet(s)
Analgésiques morphiniques/usage thérapeutique , Arthrite expérimentale/traitement médicamenteux , Buprénorphine/usage thérapeutique , Analgésiques morphiniques/pharmacologie , Animaux , Articulation talocrurale/anatomopathologie , Arthrite expérimentale/induit chimiquement , Arthrite expérimentale/anatomopathologie , Comportement animal/effets des médicaments et des substances chimiques , Poids/effets des médicaments et des substances chimiques , Buprénorphine/pharmacologie , Carbazoles/pharmacologie , Carbazoles/usage thérapeutique , Corticostérone/analyse , Corticostérone/métabolisme , Modèles animaux de maladie humaine , Algie faciale/anatomopathologie , Adjuvant Freund/effets indésirables , Hyperalgésie/traitement médicamenteux , Hyperalgésie/anatomopathologie , Mâle , Rats , Rat Sprague-DawleyRÉSUMÉ
Glucocorticoids (GCs) are critical modulators of the immune system. The hypothalamic-pituitary-adrenal (HPA) axis regulates circulating GC levels and is stimulated by endotoxins. Lymphoid organs also produce GCs; however, it is not known how lymphoid GC levels are regulated in response to endotoxins. We assessed whether an acute challenge of lipopolysaccharide (LPS) increases lymphoid levels of progesterone and GCs, and expression of steroidogenic enzymes and key HPA axis components (eg, corticotropin-releasing hormone [CRH], adrenocorticotropic hormone [ACTH]). We administered LPS (50 µg/kg intraperitoneally) or vehicle control to male and female C57BL/6J neonatal (postnatal day [PND] 5) and adult (PND90) mice and collected blood, bone marrow, thymus, and spleen 4 hours later. We measured progesterone, 11-deoxycorticosterone, corticosterone, and 11-dehydrocorticosterone via liquid chromatography-tandem mass spectrometry. We measured gene expression of key steroidogenic enzymes (Cyp11b1, Hsd11b1, and Hsd11b2) and HPA axis components (Crh, Crhr1, Pomc, and Mc2r) via quantitative polymerase chain reaction. At PND5, LPS induced greater increases in steroid levels in lymphoid organs than in blood. In contrast, at PND90, LPS induced greater increases in steroid levels in blood than in lymphoid organs. Steroidogenic enzyme transcripts were present in all lymphoid organs, and LPS altered steroidogenic enzyme expression predominantly in the spleen. Lastly, we detected transcripts of key HPA axis components in all lymphoid organs, and there was an effect of LPS in the spleen. Taken together, these data suggest that LPS regulates GC production by lymphoid organs, similar to its effects on the adrenal glands, and the effects of LPS might be mediated by local expression of CRH and ACTH.
Sujet(s)
Moelle osseuse/métabolisme , Glucocorticoïdes/biosynthèse , Lipopolysaccharides/pharmacologie , Rate/métabolisme , Thymus (glande)/métabolisme , 11-beta-Hydroxysteroid dehydrogenase type 1/génétique , 11-beta-Hydroxysteroid dehydrogenase type 2/génétique , Animaux , Animaux nouveau-nés/métabolisme , Moelle osseuse/effets des médicaments et des substances chimiques , Moelle osseuse/enzymologie , Corticostérone/analyse , Corticostérone/sang , Femelle , Glucocorticoïdes/sang , Axe hypothalamohypophysaire/effets des médicaments et des substances chimiques , Immunité innée/effets des médicaments et des substances chimiques , Mâle , Souris , Souris de lignée C57BL , Axe hypophyso-surrénalien/effets des médicaments et des substances chimiques , ARN messager/analyse , Récepteur CRH/génétique , Rate/effets des médicaments et des substances chimiques , Rate/enzymologie , Steroid 11-beta-hydroxylase/génétique , Thymus (glande)/effets des médicaments et des substances chimiques , Thymus (glande)/enzymologieRÉSUMÉ
Steroid hormones such as glucocorticoids and their metabolites are closely related to mental diseases and neuroendocrine diseases. Quantitative analysis of these substances will help in understanding their roles in related research fields. In this study, an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to detect the concentration of corticosterone (CORT) and its metabolites, progesterone (PROG) and testosterone in rat plasma and prefrontal cortex (PFC), and was applied to investigate the changes in hormones in rats with depression induced by chronic unpredictable mild stress (CUMS). The method was shown to be linear in the quantitation range for all analytes. Intra- and inter-day accuracy and precision were between 80% and 120%. Furthermore, we found that the level of CORT in plasma and PFC increased, whereas that of 11-dehydrocorticosterone (11-DHCORT) as well as the ratio of 11-DHCORT and CORT declined in rats with CUMS-induced depression. The trends of these changes in central PFC and peripheral plasma were consistent. In conclusion, this study successfully established an UPLC-MS/MS method for simultaneous measurement of CORT and its metabolites, PROG and testosterone in rat plasma and PFC, and applied it to rats with depression. The method could be further applied to the research of depression and diseases related to these steroid hormones.
Sujet(s)
Chromatographie en phase liquide à haute performance/méthodes , Corticostérone , Dépression , Cortex préfrontal/composition chimique , Stress psychologique , Animaux , Corticostérone/analyse , Corticostérone/métabolisme , Dépression/sang , Dépression/métabolisme , Modèles animaux de maladie humaine , Limite de détection , Modèles linéaires , Mâle , Rats , Rat Sprague-Dawley , Reproductibilité des résultats , Stress psychologique/sang , Stress psychologique/métabolisme , Spectrométrie de masse en tandem/méthodesRÉSUMÉ
BACKGROUND: Brain development is a prolonged process and it is sensitive to the environment during critical periods. Stress in early life is believed to increase vulnerability to depression, while enriched environment (EE) has beneficial effects on neural plasticity and depression. In this study, we compared the therapeutic effect of EE during different periods on early life stress-induced depression, and investigated the role of brain-derived neurotrophic factor (BDNF) and protein kinase B (AKT) on the effect of EE. Plasma corticosterone level was also detected to evaluate the reactivity of hypothalamic-pituitary-adrenal axis. METHODS: C57BL/6 mice were subjected to a 4-h maternal separation (MS) procedure during postnatal days 2-21. After this separation, the mice were assigned to standard environment groups (SE), EE in the early period groups (3-8 weeks, EEE) and EE in the adult groups (8-13 weeks, EEA). Depression and anxiety behavior were evaluated at 14-weeks of age. The plasma corticosterone was quantified utilizing enzyme-linked immunosorbent assay. Hippocampus BDNF and AKT/p-AKT were detected using Western blotting. RESULTS: The results showed that MS increased depression and anxiety level, while EE in both intervention periods alleviated the symptoms of depression and anxiety. The EEE group showed better effects in terms of anhedonia and anxiety than the EEA group. The difference in despair behavior between the EEE and EEA groups was not significant. MS increased plasma corticosterone level, while EE decreased corticosterone level in both intervention periods. EE increased BDNF and p-AKT expression in the hippocampus, with stronger effects in the EEE group. CONCLUSION: EE during the early development period was more effective in alleviating depression and anxiety induced by early life stress. BDNF and AKT may play a significant role in the effect of EE, and further research is needed to explore the detailed neurobiological mechanisms.
Sujet(s)
Anxiété/étiologie , Dépression/étiologie , Environnement , Facteurs âges , Animaux , Anxiété/physiopathologie , Facteur neurotrophique dérivé du cerveau/métabolisme , Corticostérone/analyse , Corticostérone/sang , Dépression/physiopathologie , Femelle , Axe hypothalamohypophysaire/métabolisme , Mâle , Séparation d'avec la mère , Souris , Souris de lignée C57BL , Plasticité neuronale/physiologie , Axe hypophyso-surrénalien/métabolisme , Protéines proto-oncogènes c-akt/métabolisme , Stress psychologique/métabolisme , Stress psychologique/physiopathologieRÉSUMÉ
Muskoxen (Ovibos moschatus), a taxonomically unique Arctic species, are increasingly exposed to climate and other anthropogenic changes. It is critical to develop and validate reliable tools to monitor their physiological stress response in order to assess the impacts of these changes. Here, we measured fecal glucocorticoid metabolite (FGM) levels in response to the administration of adrenocorticotropic hormone (ACTH) in the winter (1 IU/kg) and summer (2 IU/kg) using two enzyme immunoassays, one targeting primarily cortisol and the other targeting primarily corticosterone. Fecal cortisol levels varied substantially within and among individuals, and none of the animals in either challenge showed an increase in fecal cortisol following the injection of ACTH. By contrast, two of six (winter) and two of five (summer) muskoxen showed a clear response in fecal corticosterone levels (i.e., maximal percentage increase as compared to time 0 levels > 100%). Increases in fecal corticosterone post-ACTH injection occurred earlier and were of shorter duration in the summer than in the winter and fecal corticosterone levels were, in general, lower during the summer. These seasonal differences in FGM responses may be related to the use of different individuals (i.e., influence of sex, age, social status, etc.) and to seasonal variations in the metabolism and excretion of glucocorticoids, intestinal transit time, voluntary food intake, and fecal output and moisture content. Results from this study support using FGMs as a biomarker of hypothalamic-pituitary-adrenal axis activity in muskoxen, advance our understanding of the physiological adaptations of mammals living in highly seasonal and extreme environments such as the Arctic, and emphasize the importance of considering seasonality in other species when interpreting FGM levels.
Sujet(s)
Fèces/composition chimique , Glucocorticoïdes/métabolisme , Axe hypothalamohypophysaire/métabolisme , Ruminants/métabolisme , Hormone corticotrope/métabolisme , Hormone corticotrope/pharmacologie , Animaux , Corticostérone/analyse , Corticostérone/métabolisme , Glucocorticoïdes/analyse , Hydrocortisone/analyse , Hydrocortisone/métabolisme , Axe hypothalamohypophysaire/effets des médicaments et des substances chimiques , SaisonsRÉSUMÉ
Species that live in degraded habitats often show signs of physiological stress. Glucocorticoid hormones (e.g., corticosterone and cortisol) are often assessed as a proxy of the extent of physiological stress an animal has experienced. Our goal was to quantify glucocorticoids in free-ranging small mammals in fragments of Interior Atlantic Forest. We extracted glucocorticoids from fur samples of 106 small mammals (rodent genera Akodon and Oligoryzomys, and marsupial genera Gracilinanus and Marmosa) from six forest fragments (2-1200 ha) in the Reserva Natural Tapytá, Caazapá Department, Paraguay. To our knowledge, this is the first publication of corticosterone and cortisol levels for three of the four sampled genera (Akodon, Oligoryzomys, and Marmosa) in this forest system. We discovered three notable results. First, as predicted, glucocorticoid levels were higher in individuals living withing small forest fragments. Second, animals captured live using restraint trapping methods (Sherman traps) had higher glucocorticoid levels than those animals captured using kill traps (Victor traps), suggesting that hair glucocorticoid measures can reflect acute stress levels in addition to long-term glucocorticoid incorporation. These acute levels are likely due to urinary steroids diffusing into the hair shaft. This finding raises a concern about the use of certain trapping techniques in association with fur hormone analysis. Finally, as expected, we also detected genus-specific differences in glucocorticoid levels, as well as cortisol/corticosterone ratios.
Sujet(s)
Fourrure animale/composition chimique , Corticostérone/analyse , Forêts , Glucocorticoïdes/analyse , Hydrocortisone/analyse , Marsupialia/classification , Rodentia/classification , Animaux , Biodiversité , Femelle , Mâle , Paraguay , Stress physiologiqueRÉSUMÉ
OBJECTIVE: The effects of neonatal caffeine therapy in adults born preterm are uncertain. We studied the impact of neonatal caffeine on systemic blood pressure, vessel reactivity, and response to stress in adult mice. STUDY DESIGN: Mice pups were randomized to caffeine (20 mg/kg/d) or saline by intraperitoneal injection for 10 days after birth. We performed tail-cuff BP (8/12 weeks), urinary 8-hydroxydeoxyguanosine and fecal corticosterone (14 weeks), and vessel reactivity in aortic rings (16 weeks) in adult mice. RESULTS: No differences were noted in systolic, diastolic, and mean blood pressures between the two groups at 8 and 12 weeks of age. However, norepinephrine-induced vasoconstriction was substantially higher in aortic rings in CAF-treated male mice. More significant vasodilator responses to nitric oxide donors in aortic rings in female mice may suggest gender-specific effects of caffeine. Female mice exposed to caffeine had significantly lower body weight over-time. Caffeine-treated male mice had substantially higher fecal corticosterone and urinary 8-hydroxydeoxyguanosine at 14 weeks, suggestive of chronic stress. CONCLUSION: We conclude sex-specific vulnerability to the heightened vascular tone of the aorta in male mice following neonatal caffeine therapy. Altered vessel reactivity and chronic stress in the presence of other risk factors may predispose to the development of systemic hypertension in adults born preterm.
Sujet(s)
Pression sanguine/effets des médicaments et des substances chimiques , Caféine/pharmacologie , Vasoconstriction/effets des médicaments et des substances chimiques , 8-Hydroxy-2'-désoxyguanosine/urine , Animaux , Animaux nouveau-nés , Aorte/effets des médicaments et des substances chimiques , Caféine/effets indésirables , Corticostérone/analyse , Fèces/composition chimique , Femelle , Hypertension artérielle/étiologie , Mâle , Souris , Norépinéphrine/pharmacologie , Facteurs de risque , Facteurs sexuels , Stress physiologiqueRÉSUMÉ
Back-translating the clinical manifestations of human disease burden into animal models is increasingly recognized as an important facet of preclinical drug discovery. We hypothesized that inbred rat strains possessing stress hyper-reactive-, depressive- or anxiety-like phenotypes may possess more translational value than common outbred strains for modeling neuropathic pain. Rats (inbred: LEW, WKY, F344/ICO and F344/DU, outbred: Crl:SD) were exposed to Spared Nerve Injury (SNI) and evaluated routinely for 6 months on behaviours related to pain (von Frey stimulation and CatWalk-gait analysis), anxiety (elevated plus maze, EPM) and depression (sucrose preference test, SPT). Markers of stress reactivity together with spinal/brain opioid receptor expression were also measured. All strains variously developed mechanical allodynia after SNI with the exception of stress-hyporesponsive LEW rats, despite all strains displaying similar functional gait-deficits after injury. However, affective changes reflective of anxiety- and depressive-like behaviour were only observed for F344/DU in the EPM, and for Crl:SD in SPT. Although differences in stress reactivity and opioid receptor expression occurred, overall they were relatively unaffected by SNI. Thus, anxio-depressive behaviours did not develop in all strains after nerve injury, and correlated only modestly with degree of pain sensitivity or with genetic predisposition to stress and/or affective disturbances.
Sujet(s)
Anxiété/complications , Comportement animal , Dépression/complications , Tissu nerveux/traumatismes , Névralgie/étiologie , Névralgie/psychologie , Animaux , Comorbidité , Corticostérone/analyse , Corticostérone/métabolisme , Fèces/composition chimique , Démarche , Hyperalgésie/physiopathologie , Taille d'organe , Lignées consanguines de rats , Récepteurs aux opioïdes/métabolismeRÉSUMÉ
The measurement of corticosterone in feathers is an appealing tool for assessing glucocorticoids in wild and domestic bird species. Feather corticosterone measurements can be performed noninvasively and can provide a means for comparing glucocorticoid secretion between individual birds; thus, such measurements can be used to assess the welfare of domestic poultry. The focus of this study was to assess the validity of detecting corticosterone in turkey (Meleagris gallopavo) feathers using an ELISA and investigate differences between genetic lines. Primary feather 9 was obtained at a processing plant from 123 individuals from 3 different purebred turkey lines (line A [N = 46], line B [N = 24], and line C [N = 53]). Assay validation tests were performed using a commercially available ELISA kit (Cayman Chemicals, Cedarlane Labs, Canada). Indicators of accuracy, recovery, precision, and sensitivity were sufficient. Significant differences in feather corticosterone concentration between the 3 lines were observed. Line C had significantly higher feather corticosterone than line A (P < 0.0001) and line B (P = 0.036). These results indicate that the quantification of feather corticosterone using an ELISA is a valid method for assessing glucocorticoid levels in turkeys. This is the first report of differences in feather corticosterone between different purebred turkey lines. Differences observed between purebred lines provide an intriguing basis for further investigation into the genetic parameters of glucocorticoid levels in turkeys.
Sujet(s)
Corticostérone , Test ELISA , Plumes , Dindons , Bien-être animal , Animaux , Canada , Corticostérone/analyse , Test ELISA/médecine vétérinaire , Plumes/composition chimiqueRÉSUMÉ
Although chronic stress is an acknowledged risk factor for the development of somatic and affective disorders, the cellular and molecular mechanisms underlying stress-induced pathologies are not fully understood. Interestingly, rodent studies involving immune cell transfer suggest that CD4+ T cells might be at least in part involved in reactivation of a chemically-induced colitis by stress. However, until now evidence is lacking that these immune cell types are indeed involved in the development of a "stressed phenotype". The aim of the present study was, therefore, to assess the effects of adoptively transferring total mesenteric lymph node cells (mesLNCs) and CD4+ mesLNCs isolated from chronically-stressed mice into healthy recipient mice on various physiological, immunological and behavioral parameters. To induce chronic psychosocial stress in donor mice we employed the chronic subordinate colony housing (CSC) paradigm. Our data indicate that transfer of total or CD4+ mesLNCs from CSC mice, compared with respective cells from single-housed control (SHC) mice, promoted splenomegaly and interferon (IFN)-γ secretion from in vitro anti-CD3-stimulated mesLNCs in naïve recipient mice. This effect was independent of recipient mice additionally being administered with dextran sulfate sodium (DSS) or not. Transfer of CD4+ mesLNCs additionally increased adrenal weight and secretion of IL-6 from in vitro anti-CD3 stimulated mesLNCs in recipients administered with DSS. Importantly, transfer of neither cell type from CSC vs. SHC donor mice affected anxiety-related behavior of recipient mice in the light-dark box. Taken together, our data demonstrate that typical physiological and immunological, but not behavioral, effects of chronic stress can be induced in naïve recipient mice by adoptively transferring mesLNCs, in particular CD4+ mesLNCs, from chronically stressed donor mice.