Effects of acute and chronic restraint on the adrenal gland weight and serum corticosterone concentration of mice and their faecal output of oocysts after infection with Eimeria apionodes

Placental-fetal distribution of carbon particles in a pregnant rabbit model after repeated exposure to diluted diesel engine exhaust

BACKGROUND

Airborne pollution particles have been shown to translocate from the mother's lung to the fetal circulation, but their distribution and internal placental-fetal tissue load remain poorly explored. Here, we investigated the placental-fetal load and distribution of diesel engine exhaust particles during gestation under controlled exposure conditions using a pregnant rabbit model. Pregnant dams were exposed by nose-only inhalation to either clean air (controls) or diluted and filtered diesel engine exhaust (1 mg/m³) for 2 h/day, 5 days/week, from gestational day (GD) 3 to GD27. At GD28, placental and fetal tissues (i.e., heart, kidney, liver, lung and gonads) were collected for biometry and to study the presence of carbon particles (CPs) using white light generation by carbonaceous particles under femtosecond pulsed laser illumination.

RESULTS

CPs were detected in the placenta, fetal heart, kidney, liver, lung and gonads in significantly higher amounts in exposed rabbits compared with controls. Through multiple factor analysis, we were able to discriminate the diesel engine exposed pregnant rabbits from the control group taking all variables related to fetoplacental biometry and CP load into consideration. Our findings did not reveal a sex effect, yet a potential interaction effect might be present between exposure and fetal sex.

CONCLUSIONS

The results confirmed the translocation of maternally inhaled CPs from diesel engine exhaust to the placenta which could be detected in fetal organs during late-stage pregnancy. The exposed can be clearly discriminated from the control group with respect to fetoplacental biometry and CP load. The differential particle load in the fetal organs may contribute to the effects on fetoplacental biometry and to the malprogramming of the fetal phenotype with long-term effects later in life.

Myricitrin exhibits antidepressant-like effects and reduces IL-6 hippocampal levels in the chronic mild stress model

The flavonoid myricitrin showed an antidepressant-like effect in the tail suspension test and increased hippocampal neurogenesis, as well as demonstrating anti-inflammatory effects. Interestingly, inflammation has been linked to depression, and anti-inflammatory drugs showed promising results as antidepressant-like drugs. Thus, the present study evaluated the effects of myricitrin in the chronic mild stress (CMS) model, a translational and valid animal model of depression, using the mini-experiment design to improve the reproducibility of the findings. The sucrose preference test (SPT), forced swim test (FST), and tail suspension test (TST) were the readouts of depressive-like phenotypes induced by CMS. Relative adrenal weight was employed as an index of the hypothalamus-pituitary-adrenal (HPA) axis activation. Interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha levels were measured in the hippocampus. Myricitrin (10 mg/kg, intraperitoneally, for 14 days) reversed depressive-like behaviors induced by CMS (increased immobility in the FST, the TST and anhedonia), as well as decreased adrenal hypertrophy and hippocampal levels of IL-6 in stressed mice. Similar results were observed by imipramine (20 mg/kg, intraperitoneally, for 14 days), a serotonin and norepinephrine reuptake inhibitor (positive control). A significant correlation was observed between immobility time in the TST, and hippocampal IL-6 levels. Hippocampal TNF-α levels were not affected by CMS or drug treatment. In conclusion, myricitrin exhibited an antidepressant-like profile in CMS, and this effect may be associated with its anti-inflammatory activity.

Impact of whole-body versus nose-only inhalation exposure systems on systemic, respiratory, and cardiovascular endpoints in a 2-month cigarette smoke exposure study in the ApoE-/- mouse model

Cigarette smoking is one major modifiable risk factor in the development and progression of chronic obstructive pulmonary disease and cardiovascular disease. To characterize and compare cigarette smoke (CS)-induced disease endpoints after exposure in either whole-body (WB) or nose-only (NO) exposure systems, we exposed apolipoprotein E-deficient mice to filtered air (Sham) or to the same total particulate matter (TPM) concentration of mainstream smoke from 3R4F reference cigarettes in NO or WB exposure chambers (EC) for 2 months. At matching TPM concentrations, we observed similar concentrations of carbon monoxide, acetaldehyde, and acrolein, but higher concentrations of nicotine and formaldehyde in NOEC than in WBEC. In both exposure systems, CS exposure led to the expected adaptive changes in nasal epithelia, altered lung function, lung inflammation, and pronounced changes in the nasal epithelial transcriptome and lung proteome. Exposure in the NOEC caused generally more severe histopathological changes in the nasal epithelia and a higher stress response as indicated by body weight decrease and lower blood lymphocyte counts compared with WB exposed mice. Erythropoiesis, and increases in total plasma triglyceride levels and atherosclerotic plaque area were observed only in CS-exposed mice in the WBEC group but not in the NOEC group. Although the composition of CS in the breathing zone is not completely comparable in the two exposure systems, the CS-induced respiratory disease endpoints were largely confirmed in both systems, with a higher magnitude of severity after NO exposure. CS-accelerated atherosclerosis and other pro-atherosclerotic factors were only significant in WBEC.

Adaptogenic potential of Oxitard in experimental chronic stress and chronic unpredictable stress induced dysfunctional homeostasis in rodents

Background

Oxitard, a polyherbal formulation comprising the extracts of Withania somnifera, Mangifera indica, Glycyrrhiza glabra, Daucus carota, Vitis vinifera, powders of Syzygium aromaticum, Yashada bhasma and Emblica officinalis; and oils of Triticum sativum.

Objective

Current study deals with the assessment of Oxitard (a marketed polyherbal formulation) for its adaptogenic potential in chronic unpredictable stress (CUS) and chronic stress (CS) induced dysfunctional homeostasis in rodents.

Materials & methods

Animals were immobilized for 2 h every day for ten days to induce CS. In order to induce CUS, animals were employed in a battery of stressors of variable value and duration for ten days. Following administration of Oxitard, stress was induced in the animals. Stress-induced efficient changes were evaluated by assessing organ (adrenal gland) weights, ulcer index, hematological parameters and biochemical levels of reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and catalase (CAT).

Results

CS and CUS significantly modified the oxidative stress parameters (increased MDA and decreased GSH). Furthermore, CS and CUS lead to weight reduction, adrenal hypertrophy and gastric ulceration. Pre-treatment with Oxitard (200 and 400 mg/kg, p.o.) significantly modified CS and CUS induced hematological changes, oxidative stress parameters and pathological effects.

Conclusion

In conclusion, Oxitard-intervened antioxidant actions are accountable for its adaptogenic effects in stress-induced dysfunctional homeostasis.

Contrasting mechanisms by which social isolation and restraint impair healing in male mice

Stress modulates vital aspects of immune functioning in both human and non-human animals, including tissue repair. For example, dermal wounds heal more slowly and are associated with prolonged inflammation and increased bacterial load in mice that experience chronic physical restraint. Social stressors also negatively affect healing; however, previous studies suggest that the affected healing mechanisms may be stress model-specific. Here, the effects of either social isolation or physical restraint on dermal wound healing (3.5 mm wounds on the dorsum) were compared in hairless male mice. Social isolation beginning 3 weeks prior to wounding delayed healing comparably to physical restraint (12 h/day for eight days), in spite of marked differences in metabolic and hormonal consequences (i.e. body mass) between the two stress models. Additionally, isolated mice exhibited reductions in wound bacterial load and inflammatory gene expression (interleukin-1beta [IL-1β], monocyte chemoattractant protein [MCP]), whereas restraint significantly increased both of these parameters relative to controls. Experimentally augmenting bacterial concentrations in wounds of isolated mice did not ameliorate healing, whereas this treatment accelerated healing in controls. This work indicates that social isolation and restraint stressors comparably impair healing, but do so through disparate mechanisms and at different phases of healing.

Cyto- and chemoarchitecture of the hypothalamic paraventricular nucleus in the C57BL/6J male mouse: a study of immunostaining and multiple fluorescent tract tracing

The paraventricular nucleus of the hypothalamus (PVH) plays a critical role in the regulation of autonomic, neuroendocrine, and behavioral activities. This understanding has come from extensive characterization of the PVH in rats, and for this mammalian species we now have a robust model of basic PVH neuroanatomy and function. However, in mice, whose use as a model research animal has burgeoned with the increasing sophistication of tools for genetic manipulation, a comparable level of PVH characterization has not been achieved. To address this, we employed a variety of fluorescent tract tracing and immunostaining techniques in several different combinations to determine the neuronal connections and cyto- and chemoarchitecture of the PVH in the commonly used C57BL/6J male mouse. Our findings reveal a distinct organization in the mouse PVH that is substantially different from the PVH of male rats. The differences are particularly evident with respect to the spatial relations of two principal neuroendocrine divisions (magnocellular and parvicellular) and three descending preautonomic populations in the PVH. We discuss these data in relation to what is known about PVH function and provide the work as a resource for further studies of the neuronal architecture and function of the mouse PVH.

Studies on the protective effects of betaine against oxidative damage during experimentally induced restraint stress in Wistar albino rats

Stress can be defined as physical and psychological modifications that disrupt the homeostasis and the balance of organisms. Stress is known as one of the most important reasons of several diseases. In the present study, the anti-stress effect of betaine was evaluated with reference to its antioxidant property. Wistar albino rats were divided into four groups such as control, betaine, restraint stress (6 h/day for 30 days), and betaine + restraint stress. The oxidative damage was assessed by measuring the protein and corticosterone in plasma, lipid peroxidation, non-enzymic (reduced glutathione), and enzymic antioxidants (glutathione peroxidase, glutathione-S-transferase, catalase, and superoxide dismutase) in the lymphoid organs of thymus and spleen. Followed by the induction of restraint stress, the non-enzymic and enzymic antioxidants were significantly decreased with concomitant increase observed in the levels of corticosterone and lipid peroxidation. Oral pretreatment with betaine (250 mg/kg body weight daily for a period of 30 days) significantly (P < 0.001) prevented the restraint stress-induced alterations in the levels of protein and corticosterone in plasma of experimental groups of rats. It counteracted the restraint stress-induced lipid peroxidation and maintained the antioxidant defense system in the lymphoid tissues at near normal. The findings suggest that betaine possesses significant anti-stress activity, which may be due to its antioxidant property.

Lithium modulates the chronic stress-induced effect on blood glucose level of male rats

In the present study we examined gross changes in the mass of whole adrenal glands and that of the adrenal cortex, as well as the serum corticosterone and glucose level of mature male Wistar rats subjected to three different treatments: animals subjected to chronic restraint-stress, animals injected with lithium (Li) and chronically stressed rats treated with Li. Under all three conditions we observed hypertrophy of whole adrenals, as well as the adrenal cortices. Chronic restraint stress, solely or in combination with Li treatment, significantly elevated the corticosterone level, but did not change the blood glucose level. Animals treated only with Li exhibited an elevated serum corticosterone level and blood glucose level. The aim of our study was to investigate the modulation of the chronic stress-induced effect on the blood glucose level by lithium, as a possible mechanism of avoiding the damage caused by chronic stress. Our results showed that lithium is an agent of choice which may help to reduce stress-elevated corticosterone and replenish exhausted glucose storages in an organism.

Maternal stress and development of atherosclerosis in the adult apolipoprotein E-deficient mouse offspring

Stress is a risk factor for cardiovascular disease, such as atherosclerosis. Stress during pregnancy (maternal stress) may have long-term consequences for the health of the offspring. However, it is not known whether maternal stress affects the offspring's predisposition to develop atherosclerosis. Atherosclerosis is often related to vascular endothelial dysfunction. We hypothesized that maternal stress affects vascular endothelial function and accelerates development of atherosclerosis in offspring of apolipoprotein E-deficient mice, a model commonly used for atherosclerosis research. Stress was induced by restraining dams in small cylinders for five consecutive days (2 h/day) beginning on gestational day 8 +/- 0.5. Vascular function and development of atherosclerosis in the aorta were determined in male and female offspring at 11-15 wk of age (with early lesions) and at 22-26 wk of age (with established lesions). Endothelium-dependent vasorelaxation was determined using methacholine (0.0001-10 micromol/l) in the absence or presence of the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester hydrochloride (l-NAME; 100 micromol/l). Male offspring (11-15 wk old) from stressed dams were less dependent on nitric oxide for relaxation compared with controls (l-NAME inhibition: 38 +/- 10 vs. 69 +/- 6%, P < 0.05). Atherosclerotic lesion area was larger in male and female 25- to 26-wk-old offspring from stressed dams compared with corresponding controls [median (interquartile range): males: 6.8 (5.4-7.7) vs. 5.1 (4.4-5.5), P < 0.05, females: 10.0 (8.9-10.9) vs. 7.0 (4.7-8.7), P < 0.05]. In conclusion, maternal stress renders the apolipoprotein E-deficient offspring more susceptible to develop atherosclerosis.

Stress and hypothermia in mice in a nose-only cigarette smoke exposure system

In nose-only exposure systems, animals need to be restrained inside a tube, which leads to stress. Stress is known to cause hyperthermia in rodents. Chronically repeated episodes of hyperthermia could be detrimental to animal health and influence results of nose-only exposure studies. Therefore we investigated whether hyperthermia occurred in male C57BL/6J mice that were restrained for increasing lengths of time, using nosepieces held at room temperature, preheated at 37 degrees C, or thermostat controlled at different temperatures, with and without exposure to different concentrations of cigarette smoke. Body temperature, body weight, plasma corticosterone levels, and adrenal weights were recorded. Restraint using nosepieces at room temperature caused a time-dependent decrease in body temperature, which could be reversed by preheating the nosepieces to 37 degrees C. Cigarette smoke dose-dependently caused an additional decrease, which was counteracted by controlling nosepiece temperature at 38 degrees C. During 3 mo of exposure using heated nosepieces, Delta body temperature remained constant. Body weight gain did not differ between smoke-exposed and room air-breathing animals exposed using either heated or room-temperature nosepieces, but both groups gained significantly less weight, while adrenal weights were significantly and similarly increased, when compared to unrestrained littermates. Plasma corticosterone levels did not differ between the three groups. In conclusion, during restraint in nose-only exposure tubes with room temperature metal nosepieces, mice suffer a pronounced hypothermia. Preventing this by heating the nosepieces does not reduce the stress experienced by the animals.