Acute Immobilization Research Articles

Effects of DNA Methylation of HPA-Axis Genes of F1 Juvenile Induced by Maternal Density Stress on Behavior and Immune Traits in Root Voles (Microtus oeconomus)-A Field Experiment.

The literature shows that maternal stress can influence behavior and immune function in F1. Yet, most studies on these are from the laboratory, and replicated studies on the mechanisms by which maternal stress drives individual characteristics are still not fully understood in wild animals. We manipulated high- and low-density parental population density using large-scale field enclosures and examined behavior and immune traits. Within the field enclosures, we assessed anti-keyhole limpet hemocyanin immunoglobulin G (anti-KLH IgG) level, phytohemagglutinin (PHA) responses, hematology, cytokines, the depressive and anxiety-like behaviors and prevalence and intensity of coccidial infection. We then collected brain tissue from juvenile voles born at high or low density, quantified mRNA and protein expression of corticotropin-releasing hormone (CRH) and glucocorticoid receptor gene (NR3C1) and measured DNA methylation at CpG sites in a region that was highly conserved with the prairie vole CRH and NR3C1 promoter. At high density, we found that the F1 had a lower DNA methylation level of CRH and a higher DNA methylation level of NR3C1, which resulted in an increase in the expression levels of the CRH mRNA and protein expression and further reduced the expression levels of the NR3C1 mRNA and protein expression, and ultimately led to have delayed responses to acute immobilization stress. Juvenile voles born at high density also reduced anti-KLH IgG levels and PHA responses, increased cytokines, and depressive and anxiety-like behaviors, and the effects further led to higher coccidial infection. From the perspective of population density inducing the changes in behavior and immunity at the brain level, our results showed a physiological epigenetic mechanism for population self-regulation in voles. Our results indicate that altering the prenatal intrinsic stress environment can fundamentally impact behavior and immunity by DNA methylation of HPA-axis genes and can further drive population fluctuations in wild animals.

The restraint stress-induced antinociceptive effects decreased by antagonism of both orexin receptors within the CA1 region of the hippocampus

Studies have indicated that stress-related symptoms can lead to hormonal and neural changes, affecting the pain threshold and nociceptive behaviors. The precise role of orexin receptors (OX1r and OX2r) in stress-induced analgesia (SIA) remains an inquiry yet to be comprehensively elucidated. The current investigation aimed to assess the impact of acute immobilization restraint stress on pain-related behavioral responses after administering antagonists targeting OX1r and OX2r in a rat model using the tail-flick test. After a period of five to seven days post-stereotaxic surgery in CA1, the baseline tail-flick latency (TFL) was recorded for each animal. Subsequently, rats were unilaterally administered varying doses of the OX1r antagonist (SB334867; 1, 3, 10, and 30 nmol), the OX2r antagonist (TCS OX2 29; 1, 3, 10, and 30 nmol), or a vehicle (0.5 μl solution containing 12% DMSO) through an implanted cannula. Following a 5-min interval, the animals were subjected to a restraint stress (RS) lasting for 3 h. The tail-flick test was conducted after the stress exposure, and the TFLs were assessed at 60-min intervals. The findings of this study revealed that RS elicits antinociceptive responses in the tail-flick test. Microinjection of OX1r and OX2r antagonists into the CA1 attenuated RS-induced analgesia during the tail-flick test. Furthermore, the results underscored the preeminent role of OX2 receptors in modulating SIA. In conclusion, the orexin system localized within the hippocampal CA1 region may, in part, contribute to the manifestation of SIA in the context of acute pain.

Study Of The Stress-Protective Effect Of Sodium 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetate

The aim was to study the stress-protective effect of sodium 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetate. The analysis of the effect of the sample on the behavior and psycho-emotional state of animals, physiological parameters, antioxidant-prooxidant system was studied. Studies of stress-protective properties were performed on white outbred rats. As a comparison drug was used a Mebicar (Adaptol®) (reference sample). One hour after the simulation of immobilization 6-hour stress, the animals were subjected to a series of tests: "Open Field", "Light and Dark Chamber", "Morris Water Labyrinth". Behavioral tests were performed according to generally accepted methods in simplified modifications. Serum and liver homogenate were used to determine the content of markers of the antioxidant-prooxidant system: quantitative content of diene conjugates (DC), thiobarbituric acid reactants (TBA reactants), as well as catalase and superoxide dismutase (SOD) activity. Based on complex behavioral tests data, Catalase, TBA reactants, DC, SOD data in the serum and in the liver homogenate it can be concluded the presence of stress-protective properties of sodium 2-((4-amino-5-(thiophen-2-ylmethyl)-4H-1,2,4-triazol-3-yl)thio)acetate in the model of acute immobilization stress.

Aquatic photolysis of high-risk fluorinated liquid crystal monomers: Kinetics, toxicity evaluation, and mechanisms

Despite the frequent detection of fluorinated liquid-crystal monomers (FLCMs) in the environment, the level of understanding of their fate, toxicity, and transformation remains insufficient. Herein, we investigated the degradation kinetics and mechanism of an FLCM (4-cyano-3-fluorophenyl 4-ethylbenzoate, CEB-F) under ultraviolet (UV) photolysis in aquatic environment. Our findings demonstrated that the UV photolysis of CEB-F followed first-order kinetics. Photodegradation products were identified using liquid chromatography with mass spectrometry, and detailed reaction pathways were proposed. It is postulated that through the attack of reactive oxygen species, hydroxylation, and CO/C-F bond cleavage, CEB-F gradually degraded into small molecular compounds, releasing fluorine ions. Acute immobilization tests with Daphnia magna (D. magna) revealed significant acute toxicity of CEB-F, with LC50 values ranging from 1.023 to 0.0536 μM over 24 to 96 h, emphasizing the potential high risk of FLCMs in aquatic ecosystems if inadvertently discharged. Interestingly, we found that the toxicity of CEB-F photolysis reaction solutions was effectively reduced. Through catalase and acetylcholinesterase activities analysis along with molecular docking simulation, we proposed differences in the underlying toxicity mechanisms of CEB-F and its photolysis products to D. magna. These findings highlight the potential harmful effects of FLCMs on aquatic ecosystems and enrich our understanding of the photolysis behavior of FLCMs.

Effect of chlorpyrifos-exposure on the expression levels of CYP genes in Daphnia magna and examination of a possibility that an up-regulated clan 3 CYP, CYP360A8, reacts with pesticides.

Daphnia magna is a test organism used for ecological risk assessments of pesticides, but little is known about the expression levels of cytochrome P450s (CYP)s and their changes after pesticide exposure in the less than 24-h-olds used for ecotoxicity tests. In this study, D. magna juveniles were exposed to 0.2 μg/L of chlorpyrifos under the conditions for acute immobilization test as specified by the OECD test guideline for 24 h, and then the gene expression was compared between the control and chlorpyrifos-exposure groups by RNA-sequencing analysis, with a focus on CYP genes. Among 38 CYP genes expressed in the control group, seven were significantly up-regulated while two were significantly down-regulated in the chlorpyrifos-exposure group. Although the sublethal concentration of chlorpyrifos did not change their expression levels so drastically (0.8 < fold change < 2.6), CY360A8 of D. magna (DmCYP360A8), which had been proposed to be responsible for metabolism of xenobiotics, was abundantly expressed in controls yet up-regulated by chlorpyrifos. Therefore, homology modeling of DmCYP360A8 was performed based on the amino acid sequence, and then molecular docking simulations with the insecticides that were indicated to be metabolized by CYPs in D. magna were conducted. The results indicated that DmCYP360A8 could contribute to the metabolism of diazinon and chlorfenapyr but not chlorpyrifos. These findings suggest that chlorpyrifos is probably detoxified by other CYP(s) including up-regulated and/or constitutively expressed one(s).

Drinking Sulphate Mineral Water Action Mechanisms at Primary Preventive and Therapeutic Application under Experimental Stress: a Comparative Analysis

INTRODUCTION. Earlier in experimental studies, it was established that sulfate mineral drinking water (MB) under stress causes adaptation effects depending on the mode of its use — during primary prevention or treatment. The question of the role of different modes of drinking mineral water application in the formation of adaptation mechanisms remains unclear.&#x0D; AIM. To conduct a comparative analysis of the effect of sulfate MW in primary preventive and therapeutic application on the development of adaptive metabolic and ultrastructural reactions in rats in the early post-stress period.&#x0D; MATERIALS AND METHODS. The experiments were carried out on 54 white nonlinear male rats. Acute immobilization stress was modeled using the Selye method. All animals were divided into 5 groups: the 1st experimental group — the primary preventive effect of drinking sulfate MV; the 2nd experimental group — the therapeutic effect of drinking sulfate MV; the 3rd and 4th groups — controls; the 5th group — intact animals. Drinking sulfate MW (concentration of sulfate ions 1.93 g/l, mineralization 3.05 g/l) was administered intragastrically by 3 ml, a total of 18 procedures. Objects of research: liver and testes. Research methods: biochemical, light-optical, morphometric, electron microscopic. The statistical significance of the differences was assessed using the Student’s criterion.&#x0D; RESULTS AND DISCUSSION. It was found that the most pronounced development of adaptive-protective reactions (increased activity of the antioxidant system, increased protein synthesis, activation of intracellular regeneration processes) was observed with the action of MW in the primary prevention mode. At the same time, there was the formation of more powerful adaptation mechanisms associated with the additional accumulation of structural and metabolic resources that limit the development of maladaptation and pathological processes. With the therapeutic use of MW, due to post-stress disorders of the mechanisms of regulation, the processes of adaptation and compensation were weaker.&#x0D; CONCLUSION. The results reveal some features of the mechanism of action of drinking sulfate MW on the development of compensatory and adaptive processes and indicate the need for a differentiated approach in the use of drinking MW to increase their effectiveness in the comprehensive prevention and treatment of the body from the damaging effects of various stress factors.

Morphological changes of the hepatobiliary system and salivary glands under the influence of stress

Stress can impact our bodies at the cellular level, causing changes to various organs and systems. Chronic stress can indirectly affect the hepatobiliary tract. Salivary gland dysfunction can be a manifestation of a large variety of systemic diseases or the consequence of local structural or functional pathologies. Stress can influence the oral microbiome, leading to changes in microbial diversity. Scientists study stress reactions, new resistance methods, and modern approaches to prevent and treat stress. &#x0D; The aim is to examine the morphological aspects and changes of the blood vessels in the liver and salivary glands of white rats in experiment using acute immobilization stress.&#x0D; Materials and methods. In total 22 white male rats were studied, divided into two groups. The first was kept as a control, the second was subjected to acute immobilization stress. The rats were immobilized by hanging them by the neck with a clamp for 6 hours. Animals were euthanized with a sodium thiopental solution. Samples of the liver and parotid gland were examined histologically using hematoxylin and eosin stain.&#x0D; Results. The livers of rats were studied after acute immobilization stress. Significant changes were observed in the liver blood vessels, including thrombosis and expansion of perisinusoidal spaces. Liver cells also showed changes such as karyopyknosis, colliquation necrosis, and hydropic dystrophy. The parotid salivary gland histologic examination showed swelling in the connective tissue, periductal regions, and perivascular spaces. In the acinar section, basophilia and swelling of serocytes were observed, along with dystrophic processes leading to remodeling of the acini and ducts. The narrowing of arterioles was observed, reflecting tension in the arterial system.&#x0D; Conclusions. Exposure to acute stress can cause changes in the liver and biliary tract, increasing the risk of various diseases, including those that affect the oral cavity.

Acute toxicity of nanoscale zeolitic imidazolate framework 8 (ZIF-8) to saltwater planktonic species Artemia salina and Nannochloropsis oculata.

Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) are metal-organic frameworks (MOFs) that have gained significant attention in various fields due to their unique properties. They have potential applications in drug delivery, gas storage, and catalysis. However, their increasing use raises concerns about their potential environmental impact. Our study evaluates the effects of ≈90nm ZIF-8 NPs in two planktonic species, the green microalga Nannochloropsis oculata and the brine shrimp Artemia salina. After synthesis and characterization (SEM, EDS, BET, and DLS) of nanoporous ZIF-8 NPs, a growth inhibition test on microalgae (72h) and acute immobilization test on instar I and II of Artemia nauplii (48h) were conducted following, OECD 201 and ISO/TS 20787, respectively. The toxicity of ZIF-8 NPs to both species was time- and concentration-dependent. The 72-h median inhibitory concentration (IC50) of ZIF-8 NPs for N. oculata based on average specific growth rate and yield were calculated as 79.71 ± 8.55mg L-1 and 51.73 ± 5.16mg L-1, respectively. Also, the 48-h median effective concentration (EC50) of ZIF-8 NPs on immobilization rate of instar I and II were calculated as 175.09 ± 4.14mg L-1 and 4.69 ± 0.34mg L-1, respectively. Moreover, the swimming type of non-immobilized animals was affected by ZIF-8 NPs. These findings provide a good insight into the toxicity of nanoparticulate ZIF-8 to saltwater planktons and also confirm that instar II Artemia is more sensitive than instar I. This study demonstrated that ZIF-8 NPs, despite all their advantages, could have toxic effects on aquatic organisms. More studies are required to assess their potential environmental impact and develop strategies to mitigate their toxicity.

Epidemiology-based wastewater monitoring for ecological risks of anti-tuberculosis drugs mixture effects

First-line anti-tuberculosis (TB) drugs are commonly used to treat TB worldwide, leading to more contaminated wastewater being widely discharged into aquatic environments. However, studies of mixture interactions of anti-TB drugs and their residues in aquatic environments are scarce. This study aimed to determine the toxic interactions of anti-TB drugs—isoniazid (INH), rifampicin (RMP), and ethambutol (EMB)—in binary and ternary mixtures on Daphnia magna and used the epidemiology of TB history to construct epidemiology-based wastewater monitoring for assessing the environmental release of residues and related ecological risks. The acute immobilization of median effect concentrations (EC50) was 25.6 mg L−1 for INH, 80.9 mg L−1 for RMP, and 188.8 mg L−1 for EMB, as toxic units (TUs) for assessing mixture toxicity. The ternary mixture exhibited the lowest TUs at 50 % effects with 1.12, followed by 1.28 for RMP + EMB, 1.54 for INH + RMP, and 1.93 for INH + EMB, indicating antagonistic interactions. Nevertheless, the combination index (CBI) was used to examine the mixture toxicity in response to immobilization, revealing that the ternary mixture of CBI ranged from 1.01 to 1.08, tending to have a nearly additive effect when suffering >50 % effect (at high concentration levels). The forecasted environmentally relevant concentrations of anti-TB drugs have been on downward trends with ng L−1 level from 2020 to 2030 in Kaohsiung, Taiwan. Although ecotoxicological risks from the wastewater treatment plant and receiving water in the field were slightly greater than the prediction from epidemiology-based wastewater monitoring, there were no risk concerns. Here, we achieved the establishment of evidence that anti-TB drug mixtures' interaction and epidemiological-based monitoring support a systematic approach, resolving the absence of the mixture toxicity information for anti-TB mixture risk assessment in aquatic environments.

Administration of the glutamate-modulating drug, riluzole, after stress prevents its delayed effects on the amygdala in male rats.

Extracellular glutamate levels are elevated across brain regions immediately after stress. Despite sharing common features in their genesis, the patterns of stress-induced plasticity that eventually take shape are strikingly different between these brain areas. While stress causes structural and functional deficits in the hippocampus, it has the opposite effect on the amygdala. Riluzole, an FDA-approved drug known to modulate glutamate release and facilitate glutamate clearance, prevents stress-induced deficits in the hippocampus. But whether the same drug is also effective in countering the opposite effects of stress in the amygdala remains unexplored. We addressed this question by using a rat model wherein even a single 2-h acute immobilization stress causes a delayed expression of anxiety-like behavior, 10 days later, alongside stronger excitatory synaptic connectivity in the basolateral amygdala (BLA). This temporal profile-several days separating the acute stressor and its delayed impact-allowed us to test if these effects can be prevented by administering riluzole in drinking water after acute stress. Poststress riluzole not only prevented the delayed increase in anxiety-like behavior on the elevated plus maze but also blocked the increase in spine density on BLA neurons 10 days later. Further, stress-induced increase in the frequency of miniature excitatory postsynaptic currents recorded in BLA slices, 10 days later, was also blocked by the same poststress riluzole administration. Together, these findings underscore the importance of therapeutic strategies, aimed at glutamate uptake and modulation, in correcting the delayed behavioral, physiological, and morphological effects of stress on the amygdala.

Забруднювач довкілля бісфенол А порушує програмування статевої поведінки у жіночого потомства щурів

Bisphenol A (BPA) is a common environmental pollutant and, due to its estrogenic properties, can cause disorders of the reproductive and other physiological systems of the body, especially in males. It is known that in male rats it disrupts the sexual differentiation of the brain (SDB) of the fetus in utero. Studies of the effects of perinatal exposure of fetuses and newborn females through the mother’s body under the conditions of long-term administration of BPA during pregnancy and lactation did not reveal significant changes in SDB. Identification of long-term endocrine, neuromorphological, and behavioral consequences of exposure of female rat fetuses to a low dose of BPA administered to mothers during the last week of pregnancy, which corresponds to the temporal period of SDB, was the aim of this study. Rats were orally administered BPA suspended in Dorfman gel at a daily dose of 25 μg/kg b.w., which is 200 times less than the NOAEL (no observed adverse effect level) for rats, via a gavage, or, as a positive control, estradiol diacetate (E2D) subcutaneously at a dose of 10 μg/kg b.w., during 15-21 days of pregnancy. Control animals received gel without BPA. The levels of estradiol, testosterone, and corticosterone in blood plasma, the response of the hypothalamic-pituitary-adrenal (HPA) axis to acute immobilization stress, sexual behavior, and the histological structure and karyometric parameters of neurocytes of the medial-preoptic nuclei (MPN) of the hypothalamus were studied in adult female offspring. Prenatal exposure to BPA or E2D decreased the concentration of estradiol in the blood plasma, while the levels of testosterone and corticosterone remained normal. In the females of the BPA and E2D groups, a masculinization of sexual behavior (mounting to a receptive female, approaching her, etc.) was observed, which, according to the number of lordosis reactions in the presence of a sexually experienced male, not accompanied by her defeminization. Changes in the morphology of the MPN, which belongs to the sex-dimorphic area of the brain, conformed to the masculinization of female sexual behavior due to prenatal exposure to a low dose of BPA. Karyometry of neurocytes of the hypothalamic MPN of rats revealed no difference between the control and the BPA group. The response of the HPA axis to immobilization stress did not change in both experimental groups. It is found for the first time that maternal exposure of in utero female rat fetuses to an ultra-low relative to the NOAEL dose of BPA during the last gestational week, which corresponds to the critical period of SDB impairs programming of sexual behavior in the direction of its masculinization and causes hypoestrogenemia at adulthood. Disorders of sexual behavior conformed to morphological changes of the hypothalamic MPN. The unidirectionality of functional disorders induced by prenatal exposure to BPA and the reference estrogenic drug E2D indicates that they are caused by the estrogenic properties of both substances.

Utilization of piperonyl butoxide and 1-aminobenzotriazole for metabolic studies of toxic chemicals in Daphnia magna and Chironomus yoshimatsui

Daphnids and chironomids have been used to assess the ecological effects of chemicals released into water bodies; however, the toxicity mechanisms in organisms are generally difficult to identify. Here, we developed a system capable of estimating the contribution of cytochrome P450 (CYP) to the metabolism of test substances in Daphnia magna and Chironomus yoshimatsui based on toxicity differences in the absence and presence of the CYP inhibitors piperonyl butoxide (PBO) and 1-aminobenzotriazole (ABT). The optimum concentrations of PBO and ABT that could effectively reduce the toxicity of diazinon, which is toxic after oxidative metabolism in vivo, were determined as 0.5 and 0.6 mg/L for D. magna, and 2.0 and 40.0 mg/L for C. yoshimatsui, respectively. Acute immobilization tests of 15 insecticides were conducted for D. magna and C. yoshimatsui, with and without the optimum concentrations of PBO or ABT. In the presence of either inhibitor, chlorpyrifos and chlorfenapyr toxicity was reduced in both organisms, whereas those of thiocyclam, nereistoxin, and silafluofen were enhanced in C. yoshimatsui. Liquid chromatography-mass spectrometry analysis of D. magna and C. yoshimatsui samples exposed to chlorfenapyr confirmed that the level of the active metabolite produced by CYP was decreased by PBO or ABT in both organisms. The system to which the test substance was co-exposed to PBO or ABT will be valuable for estimating the contribution of CYPs to metabolism and elucidating the toxicity mechanism in daphnids and chironomids.

Endocrine and behavioral effects in male rats after birth with their pregnant mother taking ibuprofen

Ibuprofen, a non-selective inhibitor of cyclooxygenase, is one of the most used non-steroidal anti- inflammatory drugs (NSAID) and pain relievers. Its effect on developing fetal neuroendocrine system when taken by a pregnant mother does not well established. The aim of this study was to evaluate the long-term consequences of the administration of ibuprofen to pregnant rats with regard to hormonal profile and sexual differentiation of the brain in male offspring. Pregnant rats were given ibuprofen per os in a dose of 30 mg/kg bw twice a day during days 15-21 of gestation. On the 2 and 10 postnatal days (PND), anogenital distance (AGD) was measured in male pups. In adulthood, sexual behavior, hormone levels, and hypothalamic-pituitary-adrenal axis (HPAA) response to acute immobilization stress were studied. Prenatal ibuprofen increased AGD on PND 2 and caused incomplete masculinization of copulative behavior in adult offspring. Significant increases in the latent periods of the first mount, the first intromission, and a decrease in the number of intromissions were observed. Basal blood plasma levels of testosterone, estradiol, and corticosterone, as well as HPAA response to immobilization stress, did not change. Orchidectomized and primed with estradiol and progesterone males did not exhibit lordosis response to the presence of a sexually experienced male. Conclusion: Administration of ibuprofen to female Wistar rats during the last week of gestation disrupts partially neuroendocrine programming of male-type copulative behavior in male offspring with no changes in female-type sexual behavior and HPAA function. It is hypothesized that incomplete masculinization of the developing fetal brain with ibuprofen is due to two co-operative mechanisms: inhibition of synthesis of testosterone in the fetal gonads and prostaglandin E2 in the preoptic area of the hypothalamus.

Сучасні методи дослідження гострої токсичності полютантів для представників водної і наземної екосистем та впровадження їх у практику наукового центру превентивної та регуляторної токсикології

The paper provides a brief historical background on the formation and development of ecotoxicology as a science, reflects the main modern methods and principles for studying the acute toxicity of xenobiotics for representatives of aquatic and terrestrial ecosystems recommended by the OECD (Organization for Economic Cooperation and Development). The classification of acute ecotoxicity of chemicals for land and water test systems is given. Further perspective development of the unit, which will be aimed at expanding ecotoxicological research in accordance with international OECD methods and GLP requirements, has been outlined. Aim. Revealing the main methods and principles recommended by the OECD for determining acute toxicity for biological objects of aquatic and terrestrial ecosystems and putting these methods and principles into practice of the Scientific Centre. Materials and Methods. The work was based on the implementation of international OECD standards and GLP principles. The OECD public electronic library of methods, particularly section 2 of the Instructions for Testing Chemicals, was used and analysed. Results and Conclusions. International methods for determining the acute toxicity of pollutants for non-target environmental objects were put into practice in the Scientific Centre, such as OECD 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test); OECD 202 (Daphnia sp. Acute Immobilisation Test); OECD 203 (Fish, Acute Toxicity Test); OECD 207 (Earthworm, Acute Toxicity Tests); OECD 213 (Honeybees, Acute Oral Toxicity Test); OECD 216 (Soil Microorganisms: Nitrogen Transformation Test); OECD 217 (Soil Microorganisms: Carbon Transformation Test); OECD 223 (Avian Acute Oral Toxicity Test). Systems for the quality and control of ecotoxicological studies have been developed, which made it possible to obtain national and international accreditation for the conduct of the above studies. Further activities of the department will be aimed at expanding ecotoxicological research using international OECD methods and compliance with GLP requirements, which will contribute to the development of ecotoxicological research both in the Scientific Centre and in Ukraine as a whole. Key Words: ecotoxicology, pesticides and agrochemicals, biological test systems, OECD methods, good laboratory practice (GLP).

Involvement of the opioidergic and nociceptinergic systems in the analgesic effects of novel nociceptin analogues after acute and chronic immobilization stress

Stress is known to exert an influence on neuroendocrine, autonomic, hormonal functioning. Various stress models have been reported to induce analgesia. This is a phenomenon, referred to as stress-induced analgesia (SIA). Nociceptin/Orphanin FQ(N/OFQ) is a heptadecapeptide that has been found to play a direct role on pain perception. This study aimed to investigate the effects of novel nociceptin analogues on nociception after acute and chronic immobilization stress (CIS) and the involvement of the opioid and nociceptinergic systems in analgesic effects. Analgesic effects were examined by paw-pressure (PP) and hot-plate (HP) tests. Our data showed that acute immobilization stress induced hypoalgesia. The analgesic effect was more pronounced in pain caused by a mechanical stimulus than by a thermal one. CIS attenuated the hyperalgesic effect of naloxone and JTC-801 for mechanical and thermal stimulation. The effects of the opioid system are more pronounced in acute immobilization stress, while the nociceptin mechanisms predominate after chronic stress.

Morphological changes of the exocrine part of the pancreas under immobilization stress on the background of hypothyrosis

Annotation. Stress is a condition that causes the body's cells to use large amounts of energy to acclimate to abnormal environmental conditions. Hypothyroidism affects almost all organs and systems of the body, in particular, the pancreas. The goal of our research is to study the effect of chronic immobilization stress against the background of hypothyroidism on the tissue structure of the exocrine part of the pancreas. The experimental rats were divided into three groups: I – intact animals (10), II – animals with immobilization stress (10), III – animals with hypothyroidism and immobilization stress (10). Hypothyroidism was modeled by daily per os injection using a probe of the pharmacopoeial mercazolil thyreostatics at a dose of 25 mg/kg during the 21 day. Acute immobilization stress was modeled by tying experimental rats in a supine position in 4 limbs without restriction of head mobility for 3 hours. Histological studies were carried out according to generally accepted methods. Histological preparations were studied using a SEO SСAN light microscope and photo-documented using a Vision CCD Camera with a system of image output from histological preparations. In the 1st control group, the pancreas had a general structure plan of a parenchyme in organ. In the II group, remodeling of the exocrine part of the pancreas, slight disturbances in the structure of the acini, blood vessels, and moderate edema of the connective tissue were observed, compared to the control group of animals. In the III group, more significant changes of the gland were revealed, compared to the II experimental group, manifested by swelling and growth of connective tissue, changes in the shape of the acini, violation and loss of polarity of exocrinocytes, blood-filling of vessels. Thus, under conditions of simulated chronic stress, slight changes in the parenchyma of the gland were detected, and during chronic immobilization stress against the background of hypothyroidism, alterative changes of the gland were detected, compared to the II experimental group.

Acute immobilization stress evokes sexually dimorphic peripheral and hippocampal neuroimmune responses in adult rats

Stress perception and response vary across sexes and may contribute to the sex differences in susceptibility to psychopathology. Stress also engages the immune system and baseline immune system markers are known to be sexually dimorphic. Here, we investigated if the neuroimmune consequences following a single episode of acute immobilization stress (AIS) are sexually dimorphic in male and female Sprague-Dawley rats. We analyzed immune parameters in the periphery, and markers of neuroinflammation in the hippocampus, a key target of stress effects in the brain. We observed sexual dimorphism in the pattern of regulation of peripheral cytokines following stress, with males showing a significant increase in the levels of specific cytokines compared to females. Hippocampal cytokine and neuroinflammation-associated gene expression level analysis did not reveal any sexually dimorphic effects of AIS. However, we noted lower baseline expression levels for specific cytokines and many of the genes analyzed in the hippocampus of control females compared to control males. Finally, we assessed the levels of components of the NLRP3 inflammasome in the hippocampus and observed increased NLRP3 protein levels at baseline in females. We further noted that while males showed an increase in NLRP3 levels following AIS, females failed to show a similar change. Together, our results highlight a sexual dimorphism in neuroimmune consequences following AIS, both in the periphery and within the hippocampus, with males displaying robust proinflammatory changes and similar changes not observed in females. Our study underlines the importance of investigating the effect of sex on neuroimmune consequences following acute stress.

SUBMICROSCOPIC CHANGES IN HEMOCAPILLARIES OF ADRENAL GLAND AND PANCREATIC ISLETS OF LANGERHANS IN CASES OF IMMOBILIZATION STRESS WITH UNDERLYING HYPOTHYROIDISM

Background. Today, among the increasing number of various diseases, stress is a trigger in the development of diseases and mortality among the population. Objective. To establish submicroscopic changes in the hemocapillaries of the islets of Langerhans of the pancreas and adrenal glands in the presence of immobilization stress with underlying hypothyroidism. Methods. The experiment was carried out on 20 mature white male rats. Hypothyroidism was modeled by daily per os injection with a probe of the pharmacopoeial mercazole thyreostatics at a dose of 25 mg/kg for 21 days. Acute immobilization stress was modeled by tying the experimental rats in a supine position in 4 limbs without restricting head mobility for 3 hours. The study was conducted 2 hours later (anxiety stage) after the end of the stress impact. The material was collected for electron microscopy and tissue processing was performed according to generally accepted methods. Results. Electron microscopic examination of the blood capillaries of the islets of Langerhans in the pancreas and the hemocapillaries of the adrenal cortex after the action of the stress factor in cases of hypothyroidism showed slightly enlarged lumens and moderate perivascular edema. The basement membrane was moderately thickened but clearly contoured. Endotheliocyte nuclei were mostly hypertrophied, euchromatin was uniformly located in the nucleoplasm, and nucleoli were defined. The karyolemma was clearly contoured, the number of nuclear pores was small, and the perinuclear lumen was locally widened. Endoplasmic reticulum with moderately expanded and short tubules, moderately thickened cisterns of the Golgi complex were observed in the cytoplasm of endotheliocytes. There were two types of mitochondria: hypertrophied with an electron-light matrix, single cristae, and with clear visible cristae and a moderately electron-dense matrix. In addition to the capillaries mentioned above, there were also single narrowed microvessels that had perivascular edema and vaguely contoured fenestrae. Conclusions. When modeling a stressor in cases of hypothyroidism, structural changes of all components of the walls of blood capillaries of the pancreas and adrenal glands take place.

Immune System Response after Immobilization Stress in the Background of Ionizing Radiation

We studied the combined effect of gamma radiation (6 Gy, remote period) and immobilization stress on immunological reactivity. Materials and methods. To address this, we carried out experiments on 40 white male Wistar rats weighing 220 ± 20 g, which were divided into 4 groups: Group I - intact animals, group II - animals exposed to gamma radiation (dose of 6 Gy), group III - animals exposed to immobilization stress and group IV - animals exposed to combined exposure to gamma radiation (dose of 6 Gy) and immobilization stress. Animals in groups II and IV were irradiated 90 days before the study on the TERAGAM radiotherapeutic cobalt unit. In groups III and IV, animals were modeled for acute immobilization stress by immobilization for 6 h in bright light. Results. At the early period of immobilization stress, all indicators of the immune system, such as cellular, humoral and nonspecific phagocytic links of immunity were activated, indicating the activation of the general adaptive syndrome of the organism. The suppressive action of gamma radiation on the immune system was preserved in a remote period, with this suppression being revealed not only on the T-cellular link, but also on nonspecific phagocytic links, and the functional metabolic activity of neutrophils. In the remote period after the combined effect of sublethal gamma radiation and immobilization stress in the early stage of the adaptation syndrome, there was a decrease in all cells of the T system of immunity, in the functional ability of leukocytes, and in the mononuclear phagocytic system of the body. The experimental immobilization-radiation pathological process was accompanied by disorders of the functional activity of the essential adaptive systems of the body. Based on our results, we could conclude about the dominant role of ionizing radiation in immunological reactivity.&#x0D; HIGHLIGHTS&#x0D; &#x0D; At an early stage, after exposure to stress, the general adaptation syndrome is activated in the body&#x0D; The suppressive effect of gamma radiation on the immune status and phagocytic activity persists in the long term&#x0D; The pathological process that occurs under the combined effects of radiation and immobilization stress is accompanied by a violation of the functional activity of the most important adaptive systems of the body&#x0D; Under the combined influence of radiation and non-radiation factors, the radiation factor has a predominant influence&#x0D; &#x0D; GRAPHICAL ABSTRACT

Exploring structure/property relationships to health and environmental hazards of polymeric polyisocyanate prepolymer substances-1. Design of experiments, aquatic exposure, and acute aquatic toxicity.

Polymeric polyisocyanate prepolymer substances are reactive intermediates used in the manufacture of various polyurethane products. Knowledge of their occupational and environmental hazard properties is essential for product stewardship and industrial hygiene purposes. This work reports on the systematic design of a program to explore how structural features (i.e., types of polymeric polyol and diisocyanate reactants, functionality) and physical-chemical properties (i.e., octanol-water partition coefficient [log Kow], viscosity, molecular weight) of a group of 10 toluene diisocyanate (TDI)- and methylene diphenyl diisocyanate (MDI)-based monomer-depleted prepolymer substances can be related to their exposure and hazard potentials. The revelation of trends or thresholds in such relationships could form a basis for regulatory screening of existing or new prepolymer substances, while also informing the design of substances having reduced exposure and/or hazard profiles. As a first step, the aquatic exposure and hazard potentials of these 10 substances were investigated. The results of this investigation showed that yields of dissolved reaction products (derived from non-purgeable organic carbon measurements and carbon contents of the parent prepolymers) were inversely correlated with the calculated log Kow of the substances. For prepolymer loading rates of both 100 and 1000mg/L in water, the average dissolved reaction product yields ranged from ≤1% to 32% and from ≤0.1% to 25%, respectively, over calculated log Kow values ranging from -4.8 to 45. For both loading rates, dissolved reaction products were not quantifiable where the calculated log Kow value was >10. Yet, none of the 10 prepolymers and tested loading rates exhibited acute adverse effects on the aquatic invertebrate, Daphnia magna, in the 48-h acute immobilization test. From a product stewardship perspective, polymeric prepolymers of TDI and MDI within the investigated domain and concentration range are not expected to be hazardous in the aquatic environment.