Chronic Immobilization Stress Research Articles

The Role of Glutamine Homeostasis in Emotional and Cognitive Functions.

Glutamine (Gln), a non-essential amino acid, is synthesized de novo by glutamine synthetase (GS) in various organs. In the brain, GS is exclusively expressed in astrocytes under normal physiological conditions, producing Gln that takes part in glutamatergic neurotransmission through the glutamate (Glu)-Gln cycle. Because the Glu-Gln cycle and glutamatergic neurotransmission play a pivotal role in normal brain activity, maintaining Gln homeostasis in the brain is crucial. Recent findings indicated that a neuronal Gln deficiency in the medial prefrontal cortex in rodents led to depressive behaviors and mild cognitive impairment along with lower glutamatergic neurotransmission. In addition, exogenous Gln supplementation has been tested for its ability to overcome neuronal Gln deficiency and reverse abnormal behaviors induced by chronic immobilization stress (CIS). Although evidence is accumulating as to how Gln supplementation contributes to normalizing glutamatergic neurotransmission and the Glu-Gln cycle, there are few reviews on this. In this review, we summarize recent evidence demonstrating that Gln supplementation ameliorates CIS-induced deleterious changes, including an imbalance of the Glu-Gln cycle, suggesting that Gln homeostasis is important for emotional and cognitive functions. This is the first review of detailed mechanistic studies on the effects of Gln supplementation on emotional and cognitive functions.

Olive oil Ameliorates renal Ischemia-reperfusion-mediated hepatic and renal changes in stressed rats

Background: Renal ischemia-reperfusion injury (IRI) does not only affect kidneys, but also affects remote organs especially the liver. Stress may lead to further progression of renal and hepatic insults. This study was planned to explore the efficacy of olive oil (OO) on the assumed renal and hepatic changes of immobilization stress following renal IRI. Methods: Seventy-seven adult male Wistar albino rats were divided into the following five groups; Sham-Operated Control group, Renal Ischemia-Reperfusion group, Stressed Renal Ischemia-Reperfusion group, OO-Supplemented Renal Ischemia-Reperfusion group) and OO-Supplemented Stressed Renal Ischemia-Reperfusion Group (OO+Stressed+IR). All animals were subjected to determination of renal and hepatic biochemical functions and histopathological examination. Results: Renal IR significantly increased plasma creatinine and urea levels. This was associated with significant rise in serum levels of both ALT and AST, total bilirubin together with plasma level of TNF-[Formula: see text], whereas the plasma level of albumin (ALB) was significantly reduced. In addition, histological disruptions of kidneys and livers were observed. Chronic immobilization stress aggravated the effects of renal IR. Also, renal and hepatic morphological changes were more worsened. Whilst, OO supplementation resulted in significant amelioration of renal and hepatic functions. Also, the kidney and liver morphologic lesions were attenuated. Conclusion: Renal IR not only affected the renal functional and structural integrity but also the remote organ, the liver. Chronic immobilization stress rendered the kidney and liver more prone to injury. OO improved renal and hepatic dysfunction and morphological damage mediated by renal IRI, in control rats and in those exposed to chronic stress which can be exerted partially via its antioxidant, anti- inflammatory and nitric oxide (NO) reducing activities.

Age characteristics of myocardial blood supply in comorbid pathology

Understanding the age-related changes in myocardial blood supply under conditions of diabetes mellitus and stress will help reveal the pathway of diabetic cardiomyopathy, considering the age aspect. Therefore, the aim of our work is to investigate the age-related morpho-functional changes in the hemomicrocirculatory bed (HMB) of the myocardium in rats with experimental streptozotocin-induced diabetes mellitus (SDM) under conditions of chronic immobilization stress (CIS). The study used heart fragments and blood from 56 2-month-old and 6-month-old male white rats, which were divided into 3 groups: 1 group with comorbid pathology, including modeled SDM and CIS, 2 group with SDM, and 3 – control group. The material was collected 14th and 56th days from the start of the experiment. According to our findings, hyperglycemia, and stress on the 14th day of the experiment lead to spasm of the arterioles of the HMB and a significant deterioration in their permeability, as evidenced by a likely increase in the Vongenwort index in the arterioles. On the 56th days, in the experimental groups of 6-month-old rats, vacuolar dystrophy and coagulation necrosis of endotheliocytes and myocytes, focal destruction of capillary walls, thickening, and proliferation of their basement membrane, pronounced micro- and macroclasmatic changes, and capillarosclerosis are observed. In contrast, 2-month-old rats alongside destructive changes in HMB vessels show phenomena of neovascularization. Thus, SCD leads to the development of diabetic microangiopathy in the vessels of the myocardium of rats of different age groups. In animals with comorbid pathology, damage of HMB vessels are more pronounced on the 56th day of observation and is manifested by: destruction of capillary walls, capillarosclerosis. In 2-month-old rats, alongside destructively changed capillaries, we found to former new vessels with a characteristic ultrastructure. Keywords: heart, heart failure, diabetic cardiomyopathy, diabetes mellitus, cardiovascular diseases, hemomicrocirculatory bed.

Chia seeds oil ameliorate chronic immobilization stress-induced neurodisturbance in rat brains via activation of the antioxidant/anti-inflammatory/antiapoptotic signaling pathways

Chronic immobilization stress plays a key role in several neuropsychiatric disorders. This investigation assessed the possible ameliorative effect of chia seed oil (CSO) against the neurodisturbance-induced in rats by chronic immobilization. Rats were randomly allocated into control, CSO (1 ml/kg b.wt./orally), restrained (6 h/day), CSO pre-restraint, and CSO post-restraint for 60 days. Results revealed a significant reduction in serum corticosterone level, gene expression of corticotrophin-releasing factor, pro-inflammatory cytokines, and oxidative biomarkers in restrained rats treated with CSO. The histopathological findings revealed restoring necrosis and neuronal loss in CSO-treated-restraint rats. The immunohistochemical evaluation revealed a significant reduction in the immuno-expression of caspase-3, nuclear factor kappa B, interleukin-6, and cyclooxygenase-2 (COX-2), and an elevation of calbindin-28k and synaptophysin expression compared to non-treated restraint rats. The molecular docking showed the CSO high affinity for several target proteins, including caspase-3, COX-2, corticotropin-releasing hormone binding protein, corticotropin-releasing factor receptors 1 and 2, interleukin-1 receptor types 1 and 2, interleukin-6 receptor subunits alpha and beta. In conclusion, CSO emerges as a promising candidate against stress-induced brain disruptions by suppressing inflammatory/oxidative/apoptotic signaling pathways due to its numerous antioxidant and anti-inflammatory components, mainly α-linolenic acid. Future studies are necessary to evaluate the CSO therapeutic impacts in human neurodisturbances.

Effects of Phragmanthera capitata (Loranthaceae) on a model of anxiety-like behaviours induced by chronic immobilization stress in mice

This work aims to evaluate the anxiolytic-like effects of Phragmanthera capitata in a model of chronic immobilization stress in mice. Groups of mice were treated in ten consecutive days as follows: a normal control group (NaCl 0.9% per os), a negative control group (chronic immobilization stress + NaCl 0.9% per os), three test groups that were submitted to chronic immobilization stress (CIS) and received three doses of the plant (25, 125, and 250 mg/kg, p.o), and a positive control group (chronic immobilization stress + diazepam 2 mg/kg, i.p). Open field and dark/light tests were used for the evaluation of anxiolytic effects. Antioxidant activities and the involvement of gabaergic neurotransmission were determined by measuring the levels of malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), gamma amino butyric acid (GABA), and GABA-transaminase (GABA-T) in the brain. Our results show that the highest dose of Phragmanthera capitata induced a significant increase (p < 0.001) of time spent in the centre, number of crossing and number of grooming in the open field test and a significant increase (p < 0.001) of time spent in the light compartment and the latency of the first escape in the light compartment of the dak/light test. The level of MDA and the activity of GABA-T were significantly decreased by the Phragmanthera capitata while reduced GSH, CAT and GABA, levels were increased. These results suggest that Phragmanthera capitata possesses anxiolytic-like effects that may be supported by its antioxidant activities and or the GABA neurotransmission.

Morphologic characteristic of rat myocardium in comorbid pathology

Diabetic cardiomyopathy is a serious complication of diabetes mellitus (DM). Aim. Therefore, we aimed to study myocardial changes in adult rats with streptozotocin (STZ)-induced DM exposed to chronic immobilization stress (CIS). Materials and methods. A total of 26 adult albino male rats weighing 180–200 g were examined. All the animals were divided into three groups: Group I included 10 rats with STZ-induced DM exposed to CIS; Group II comprised 10 rats with STZ-induced DM; Group III included 6 intact animals. The samples were collected on the 14th and 56th days of the experiment. Histological, histochemical, electron microscopy, and biochemical methods were used. Results. On the 14th day of the experiment, in Group I and Group II, increased blood flow was observed in the capillaries, venules, and veins, while an arteriolar spasm in the microcirculation was found. In addition, cardiomyocyte surface area in different myocardial regions reduced due to low glycogen content as confirmed by histochemical and ultrastructural studies. On the 56th day of the experiment, in Group I and Group II, hyperemia occurred due to red blood cell aggregation and microthrombi. The surface area of all microcirculatory vessels increased as compared to that of intact animals, as evidenced by an increase in their wall surface area leading to an increase in their wall-to-lumen ratio. Such morphometric changes in the microcirculatory vessels were indicative of decreased vascular permeability and impaired myocardial blood flow. At the histological level, in Group I and Group II, focal cardiomyocyte lysis, moderate to diffuse stromal edema, lymphohistiocytic infiltration were seen. Such changes pointed to sterile inflammation, probably due to myocardial infraction secondary to diabetic microangiopathy. In cardiomyocytes, karyolysis, vacuolar degeneration, apical ballooning, subsarcolemmic edema, fibrosis and lysis of myofibrils, colliquative necrosis were observed. Conclusions. STZ-induced DM and stress resulted in pronounced destructive changes in the myocardium of rats, including interstitial edema, focal cardiosclerosis, myolysis. Such changes occurred on the background developing diabetic microangiopathy. The most pronounced myocardial changes were recorded in animals with a comorbidity.

THE EFFECT OF CHRONIC IMMOBILIZATION STRESS ON THE CONTENT OF MICRO- AND MACROELEMENTS IN THE PANCREAS AND BLOOD SERUM OF RATS AND THEIR NEWBORN OFFSPRING

Have been considered the role of macro- and microelements - Ca, Mg, Zn, Fe, and Cu imbalance in the blood serum and pancreatic tissue homogenate of rats, whose pregnancy took place against the background of chronic immobilization stress and their newborn

Regionalized analysis of gut barrier components in the small intestine of BALB/c mice following chronic immobilization stress.

Microbiota and tight junction proteins (TJPs) are components of the gut barrier, and are considered stress targets that have deleterious effects on intestinal homeostasis. This study aimed to evaluate the effects of chronic immobilization stress on selected small intestine homeostasis parameters. Female BALB/c mice were divided into a stress group that underwent short-term immobilization for 2 h per day for 4 consecutive days, and a non-stressed control group (n = 6 per group). Proximal and distal small intestine samples were excised to assess colony-forming units per gram (CFU/g) of total bifidobacteria in selective agar plates, luminal albumin was assessed using immune-enzymatic assay, pro-inflammatory cytokines were evaluated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and TJPs (pore-forming, claudin (Cld)-2; pore-sealing, Cld-4; ambiguous, Cld-7, -12 and -15) were assessed with RT-qPCR and western blotting. Compared with the control group, the stress group had lower body weight and energy intake. In the distal region, the stressed mice had lower bifidobacteria count and messenger ribonucleic acid (mRNA) expression of Cld-2, Cld-4 and Cld-12, though they had more albumin and higher interleukin (IL)-6 mRNA expression. Within the proximal region, the stressed mice had higher mRNA expression of tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), IL-6, Cld-7, Cld-12, and Cld-15, along with lower levels of IL-10 and Cld-4. However, mRNA and protein expression of TJPs were discordant. These findings indicate divergent stress-induced outcomes in the small intestine, evidenced by the elicitation of a pro-inflammatory response and decreased anti-inflammatory response in the duodenum, and by increased albumin transudation and decreased bifidobacterial growth in the distal region.

Protective Properties of Marine Alkyl Glycerol Ethers in Chronic Stress

In this paper we discuss the effect of alkyl glycerol ethers (AGs) from the squid Berryteuthis magister on a chronic stress model in rats. The study was performed on 32 male Wistar rats. Animals received AGs at a dose of 200 mg/kg through a gavage for six weeks (1.5 months), and were divided into four groups: group 1 (control), group 2 (animals received AGs), group 3 (stress control), group 4 (animals received AGs and were subjected to stress). Chronic immobilization stress was induced by placing each rat into an individual plexiglass cages for 2 h daily for 15 days. The serum lipid spectrum was evaluated by the content of total cholesterol, triglycerides, high-density lipoprotein cholesterol, low lipoprotein cholesterol and very low-density lipoprotein cholesterol. The atherogenic coefficient was calculated. The hematological parameters of peripheral blood were evaluated. The neutrophil-lymphocyte ratio was counted. The levels of cortisol and testosterone in blood plasma were determined. AGs at the selected dose did not have a significant effect on the body weight of rats in the preliminary period of the experiment. Under stress, the body weight gain, the concentrations of very low-density lipoprotein cholesterol and blood triglycerides decreased significantly. The neutrophil-lymphocyte ratio in animals treated with AGs shifted towards lymphocytes. A favorable increase in the percentage of lymphocytes was found in the stressed group of animals treated with AGs. So, for the first time, it was found that AGs prevent stress-induced suppression of the immune system. This confirms the benefit of AGs for the immune system under chronic stress. Our results prove the efficiency of the use of AGs for treating chronic stress, a serious social problem in modern society.

Antidepressant and anxiolytic effects of melaleuca cajuputi essential oil on chronic immobilization stress (CIS)-Induced mice model

The preliminary studies showed that Melaleuca cajuputi essential oil (MCEO) contained several phytochemicals of antidepressant and anxiolytic properties. Therefore, the aim of this study is to evaluate the antidepressant and anxiolytic effects of MCEO on chronic immobilization stress (CIS)-induced mice.Eight groups of male Swiss albino mice were divided into control, CIS+DMSO, CIS+amitriptyline and CIS+MCEO at different concentrations (1, 2.5, 5, 7.5 and 10% v/v). All mice groups except the control were subjected to a 2-hours CIS procedure for 15 days. All MCEO treatments were administered through the inhalation route, while the amitriptyline was via intraperitoneal from day 16 to 20. The anxiolyticandantidepressant effects of MCEO were evaluated via behavioural tests, histopathological changes and corticotrophin-releasing hormone (CRH) level on day 21. Results were analysed using one-way ANOVA followed by Dunnet’s posthoc test with the significant level of P<0.05.At its lowest concentration (1% v/v), MCEO has significantly reduced depression-like behaviour, while the anxiolytic effect appeared at concentration 5% v/v. The mice’s body weights were significantly increased (P<0.0001) at the concentrations of 5, 7.5 and 10% v/v. Meanwhile, at 7.5 and 10% v/v, MCEO able to significantly increase the granular cell layer (GCL) and pyrimidal cell layer (PCL) surface areas (P<0.05). For CRH level, it has been reduced from the lowest MCEO concentration. MCEO exhibited antidepressant and anxiolytic effects, probably due to the phytochemical constituents that regulated in the CRH pathway which lead to an increase of the GCL and PCL surface areas.

Study of effects of newly synthesised nociceptin analogues on the endocannabinoid system and pain after chronic immobilization stress

Study of effects of newly synthesised nociceptin analogues on the endocannabinoid system and pain after chronic immobilization stress

MORPHOLOGICAL CHARACTERISTICS OF THE ENDOCRINE FUNCTION OF THE HEART IN COMORBID PATHOLOGY.

Aim: To study the ultrastructural remodeling of atrial myoendocrine cells (AMC) of the atrial myocardium in streptozotocin-induced diabetes (SID) under chronic immobilization stress (CIS). Materials and methods: 40 sexually mature white male rats (body weight 150-180 g) were included in the study. Four groups were formed: group 1 - animals with comorbid pathology (SID and CIS), group 2 - animals with SID, group 3 - animals with CIS, group 4 - intact animals. Results: On the 14th day of the development of SID and CIS, an increase in the functional activity of AMC is noted, which is confirmed by hyperplasia and hypertrophy of the protein-synthesizing apparatus, an increase in the volume density of secretory granules (SG), especially diffusing ones, and indicates enhanced release of atrial natriuretic peptide (ANP) from cells during the experiment. On the 56th day of the experiment, in groups 1 and 2 of , destructive changes in AMC were noted, such as vacuolar and balloon dystrophy, colliquative and partial necrosis. At the same time, the functional activity of AMC of different regions of the myocardium significantly. In animals with CIS, the volume density of young and diffusing SG in AMC is decreased. Conclusions: Therefore, in the early stages of the development of SID and CIS, an increase in the morpho-functional activity of AMC is noted. The long course of SID and its combination with CIS lead to destructive changes in AMC and to decrease in their secretory activity.

Comparative evaluation of natural neuroprotectives and their combinations on chronic immobilization stress-induced depression in experimental mice.

The present study evaluates the potential of neuroprotective phytochemicals-rutin (R), resveratrol (Res), 17β-estradiol (17β-E2), and their different combinations against chronic immobilization stress (CIS)-induced depression-like behaviour in male albino mice. Here, the mice were exposed to stress via immobilization of their four limbs under a restrainer for 6h daily until 7days of the induction after 30min of respective drug treatment in different mice groups. The result found the protective effect of these phytoconstituents and their combinations against CIS-induced depression due to their ability to suppress oxidative stress, restore mitochondria, HPA-axis modulation, neurotransmitter level, stress hormones, and inflammatory markers. Also, the combination drug regimens of these phytoconstituents showed synergistic results in managing the physiological and biochemical features of depression. Thus, these neuroprotective could be utilized well in combination to manage depression-like symptoms during episodic stress. Furthermore, such results could be well justified when administered in polyherbal formulation with these neuroprotective as major components. In addition, an advanced study can be designed at the molecular and epigenetics level using a formulation based on these neuroprotective.

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.

Chaihu Shugan powder alleviates liver inflammation and hepatic steatosis in NAFLD mice: A network pharmacology study and in vivo experimental validation.

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common metabolic disease and is intertwined with cardiovascular disorders and diabetes. Chaihu Shugan powder (CSP) is a traditional Chinese medicine with a significant therapeutic effect on metabolic diseases, such as NAFLD. However, its pharmacological mechanisms remain to be elucidated. Methods: The main compounds of CSP were measured using LC-MS/MS. A network pharmacology study was conducted on CSP. Its potential active ingredients were selected according to oral bioavailability, drug similarity indices, and phytochemical analysis. After obtaining the intersected genes between drug targets and disease-related targets, the component-disease-target network and protein-protein interaction analysis were visualized in Cytoscape. GO and KEGG enrichment analyses were performed using the Metascape database. Six-week-old male C57BL/6 mice fed a high-fat high-fructose diet for 16 weeks plus chronic immobilization stress for 2 weeks, an in vivo model, were administered CSP or saline intragastrically. Liver histology, triglyceride and cholesterol levels, ELISA, and RT-PCR were used to assess hepatic inflammation and steatosis. Immunohistochemistry and western blotting were performed to assess protein levels. Results: A total of 130 potential target genes in CSP that act on NAFLD were identified through network pharmacology assays, including tumor necrosis factor (TNF), interleukin-6 (IL6), interleukin-1β (IL-1β), and peroxisome proliferator-activated receptor γ (PPARG). KEGG enrichment analysis showed that the main pathways were involved in inflammatory pathways, such as the TNF and NF-κB signaling pathways, and metabolism-related pathways, such as the MAPK, HIF-1, FoxO, and AMPK signaling pathways. The results in vivo showed that CSP ameliorated liver inflammation and inhibited hepatic fatty acid synthesis in the hepatocyte steatosis model. More specifically, CSP therapy significantly inhibited the expression of tumor necrosis factor α (TNFα), accompanied by a decrease in TNF receptor 1 (TNFR1) and the ligand availability of TNFR1. Conclusion: Through the combination of network pharmacology and in vivo validation, this study elucidated the therapeutic effect of CSP on NAFLD, decreasing liver inflammation and inhibiting hepatic fatty acid synthesis. More specifically, the anti-inflammatory action of CSP was at least partially mediated by inhibiting the TNFα/TNFR1 signaling pathway.

Maternal programming by high-energy diets primes ghrelin sensitivity in the offspring of rats exposed to chronic immobilization stress

Maternal overnutrition during pregnancy leads to metabolic and immune alterations, including obesity, hyperphagia, and central and peripheral inflammation in offspring. Exposure to high-energy diets during pregnancy primes ghrelin sensitivity to overfeeding in the offspring at early stages of life. Overfeeding has also been partially related to the early stages of chronic stress. We hypothesized that maternal programming sensitizes ghrelin-induced overfeeding following a chronic stress schedule in the offspring. We used a nutritional programming model exposing female Wistar rats to a cafeteria (CAF) or control diet from prepregnancy to weaning. Male offspring were injected with ghrelin and then subjected to a chronic immobilization stress (CIS) schedule, after which food intake was determined. Hypothalamic and plasma accumulation of cytokines and cortisol were evaluated using BioPlex analysis and enzyme-linked immunosorbent assay, respectively. We found that rats exposed to the CAF diet exhibited overfeeding after fasting and peripheral ghrelin administration, which was exacerbated in rats exposed to chronic stress. Offspring exposed to the CAF diet accumulated pro-inflammatory interleukin-6 (IL-6), interferon-γ, and monocyte chemoattractant protein-1 cytokines in plasma, and IL-6 cytokine in the hypothalamus. Ghrelin-sensitive overfeeding in rats exposed to CAF diet + CIS display increased cortisol levels and decreased IL-6 accumulation in plasma. Together, our results suggest that maternal nutritional programming primes susceptibility to ghrelin response for overfeeding after a CIS schedule that mirrors plasma cortisol accumulation in male offspring.

HYPOGLYCEMIC ACTIVITY OF $ORIGANUM~VULGARE$ L. AQUEOUS EXTRACT IN HYPERGLYCEMIA INDUCED BY IMMOBILIZATION STRESS IN RABBITS

Currently diabetes mellitus (DM) is a worldwide problem linked to hyper-glyce¬mia and has affected people both in developing and developed countries. DM is divided into Type 1 (T1DM) and Type 2 (T2DM). Moreover, the T2DM is the most prevalence form that encompasses a reduce responsiveness to insulin-sensitive cells or defects in insulin secretion. Exposure to chronic immobilization stress contributes to the development of hyperglycemia and hyperlipidemia that can lead to cardiovascular complications. Herbs with hypoglycemic properties, especially Origanum vulgare L., would be useful in hyperglycemia treatment. Oral administration of aqueous extract showed significant effect on hyperglycemia and improving glucose tolerance. In addition, extract of O. vulgare reduced total cholesterol, low-density lipoprotein cholesterol levels, and vice versa increased high-density lipoprotein cholesterol levels, and also decreased liver enzymes levels (alanine aminotransferase and aspartate aminotransferase) compared with untreated group and might be recommended as herbal remedy in the treatment of stress-induced hyperglycemia.

TLR4 in Tph2 neurons modulates anxiety-related behaviors in a sex-dependent manner

TLR4 belongs to the TLR receptor family and can induce a proinflammatory response to invading pathogens. Recent studies have identified that TLR4 is associated with major anxiety disorder. Tph2 is a rate-limiting enzyme for 5-HT biosynthesis that is expressed at high levels in the DRN, which includes the main 5-HT projection to the hippocampus and prefrontal cortex and regulates anxiety disorder. Here, we show that TLR4 expressed in Tph2 neurons in the DRN can modulate anxiety-like behaviors in a sex-dependent manner. Deletion of TLR4 in Tph2 neurons decreases anxiety-like behaviors in male but not in female mice. Meanwhile, a similar phenotype was found by selectively ablating TLR4 in the DRN of adult male but not female mice using AAV-Cre-GFP virus. Inhibition of TLR4 in DRN by infusion of LPS-RS via intra-Aq is sufficient to reverse anxiety-like behavior induced by chronic immobilization stress (CIS). The underlying mechanisms seem to involve alterations in the activity of Tph2 neurons and key components of 5-HT transmission, including synthesis, reuptake, and transmission. Our results suggest that TLR4 in Tph2 neurons is a key modulator in anxiety-like behaviors and the 5-HT system in the brain between different sexes.

Abstract 2191: Alteration of anti-tumoral immunity in the pre-metastatic bone microenvironment via autonomic nerve system dysfunction

Abstract Bone metastasis is a major cause of morbidity and mortality for breast cancer patients. Bone is a unique metastatic microenvironment because of complex interactions among numerous distinct cell types such as osteo-blasts, -clasts, -cytes and marrow immune cells in physiological and pathological conditions. Imbalanced bone homeostasis by diverse factors such as the sympathetic nerve system (SNS) activation, potentially contribute to the progression of bone metastasis, yet precise mechanisms remain unclear. We investigated the effects of beta 2 adrenergic receptor (β2AR) activation in osteoblasts induced by prolonged SNS stimulation on anti-tumoral immunity in bone metastasis. We treated female Balb/C with chronic immobilization stress (CIS; 2 h. daily) and found that CIS increased syngeneic intra-tibial 4T1 bone metastasis growth as well as the number of CD11b+Gr1+ myeloid-derived suppressor cells (MDSC) counterbalancing anti-tumoral cytotoxic T cells in bone microenvironment. A β2AR-specific inhibitor (ICI-118551) or MDSC depletion using anti-Gr1 antibodies reversed CIS-induced bone metastatic tumor growth. More importantly, 2-week CIS pre-treatment increased EDU+ MDSC proliferation in the bone marrow, contributing to subsequent bone metastatic tumor growth and micro-metastatic seeding in intra-tibial and intra-cardiac tumor injection models, respectively. When CIS was administered after the establishment of bone metastatic tumors, the pro-tumorigenic effects were marginal. In osteoblast-specific β2AR knockout mice (Adrb2flox/flox; murine 2.3kb Col1-CreC57BL6 mice), CIS did not increase MDSC proliferation compared with littermate floxed controls, suggesting that β2AR in osteoblasts upregulates MDSC in bone microenvironment. RNA-sequencing transcriptome analysis of saline- or clenbuterol (a selective β2AR agonist)-treated murine osteoblasts showed that interleukin-6 (IL6) was the most significantly increased cytokine. Indeed, CIS or clenbuterol treatment increased IL-6 expression in vivo (immunohistochemistry) and in vitro (cultured osteoblasts), respectively. MDSC isolated from the bone marrow of CIS-treated mice had significantly increased STAT3 phosphorylation by flow cytometry and the expression of immuno-suppressive functional molecules such as arginase 1 (Arg1) and indolamine 2,3-dioxygenase 1 (Ido1) compared to those from control mice. Our data collectively demonstrated that SNS-dependent β2AR in osteoblasts expands and activates MDSC in the pre-metastatic bone microenvironment via the IL6-STAT3-Arg1/IDO1 pathway, creating a fertile soil for bone metastasis progression. Our data provided the first direct evidence for anti-tumoral immunity and pro-tumorigenic effects of autonomous nerve system dysfunction specific to the metastatic bone microenvironment. Citation Format: Eun Jung Lee, Da Hyeon Yun, Seungpil Jung, Serk In Park. Alteration of anti-tumoral immunity in the pre-metastatic bone microenvironment via autonomic nerve system dysfunction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2191.