Injection Of Lipopolysaccharide Research Articles

Hypoxia-Preconditioned Human Umbilical Cord Mesenchymal Stem Cells Transplantation Ameliorates Inflammation and Bone Regeneration in Peri-Implantitis Rat Model.

The failure of dental implant treatments is predominantly attributed to peri-implantitis, which entails chronic inflammation within the peri-implant tissue, ultimately leading to tissue degradation. Addressing this condition, human umbilical cord mesenchymal stem cell (hUCMSC) transplantation serves as a regenerative therapy; however, concerns regarding the viability and efficacy of transplanted cells in inflamed regions persist. Hypoxic preconditioning of hUCMSCs has emerged as a potential strategy for augmenting their regenerative and immunomodulatory capacities. This study aimed to evaluate the expression of inflammatory (tumor necrosis factor [TNF]-α) and bone regenerative biomarkers (nuclear factor of activated T-cell [NFATc1], osteocalcin, collagen type I alpha 1 [COL1α1]) within peri-implantitis models subsequent to the transplantation of hypoxia-preconditioned hUCMSCs. Peri-implantitis models were established through the insertion of implants into the femur bone of 42 Wistar strain Rattus norvegicus, followed by intrasocket injection of lipopolysaccharide. The experimental animals were categorized into three groups (control, normoxia, and hypoxia) and underwent observation on days 14 and 28. The expression levels of TNF-α, NFATc1, COL1α1, and osteocalcin were evaluated using immunohistochemical staining, and the resulting data were subjected to one-way analysis of variance analysis (p < 0.05). Transplantation of hypoxia-preconditioned hUCMSCs significantly ameliorated inflammation and osteoclastogenesis, as evidenced by significant reductions in TNF-α and NFATc1 expression compared with the control group. Furthermore, hypoxic preconditioning of hUCMSCs demonstrated a significant elevation in the expression of osteocalcin and COL1α1 relative to the control group. The transplantation of hypoxia-preconditioned hUCMSCs exhibited a capacity to ameliorate inflammation and enhance bone regenerative processes in peri-implantitis rat models.

Epigenetic Mechanisms of the Anti-inflammatory Action of the Opioid Peptide Leutragin: Role of Sirtuin 1

Sirtuin 1 (SIRT1) is a class III histone deacetylase that plays a key role in resolving inflammation through known epigenetic mechanisms involving histone and nuclear factor κB (NF-κB) deacetylation. Deacetylation reduces the transcriptional activity of NF-κB and the associated production of pro-inflammatory cytokines such as interleukin 1β (IL-1β), tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6). In the present study, we show for the first time that biomodeling of acute lung inflammation by a single injection of lipopolysaccharide (LPS) induces synchronous oscillations of mRNA levels of cytokines IL-1β, TNF-α, IL-6 and SIRT1 deacetylase in the lungs, the maximum amplitudes of cytokine mRNA oscillations are observed between 1.5 and 5 hours, whereas high levels of SIRT1 mRNA are observed up to 24 hours, when cytokine mRNA oscillations have already faded, which is consistent with the hypothesis about the role of SIRT1 as a factor acting in the phase of inflammation resolution. The study shows that the mechanism of anti-inflammatory action of inhaled hexapeptide Leutragin, a δ-opioid receptor agonist, is related to its ability to increase SIRT1 mRNA expression and decrease the amplitudes of IL-1β, TNF-α, and IL-6 mRNA oscillations in the lungs, which generally leads to the resolution of inflammation in the conditions of biomodeling of acute lung inflammation.

Systemic inflammation accelerates neurodegeneration in a rat model of Parkinson's disease overexpressing human alpha synuclein.

Increasing efforts have been made to elucidate how genetic and environmental factors interact in Parkinson's disease (PD). In the present study, we assessed the development of symptoms on a genetic PD rat model that overexpresses human α-synuclein (Snca+/+) at a presymptomatic age, exposed to a pro-inflammatory insult by intraperitoneal injection of lipopolysaccharide (LPS), using immunohistology, high-dimensional flow cytometry, constant potential amperometry, and behavioral analyses. A single injection of LPS into WT and Snca+/+ rats triggered long-lasting increase in the activation of pro-inflammatory microglial markers, monocytes, and T lymphocytes. However, only LPS Snca+/+ rats showed dopaminergic neuronal loss in the substantia nigra pars compacta (SNpc), associated with a reduction in the release of evoked dopamine in the striatum. No significant changes were observed in the behavioral domain. We propose our double-hit animal as a reliable model to investigate the mechanisms whereby α-synuclein and inflammation interact to promote neurodegeneration in PD.

Photobiomodulation Therapy at 660 nm Inhibits Hippocampal Neuroinflammation in a Lipopolysaccharide-Challenged Rat Model

Background/Objectives: Neuroinflammation is associated with the progression of various brain diseases, and the management of neuroinflammation-induced neural damage is a crucial aspect of treating neurological disorders. This study investigated the anti-inflammatory efficacy of photobiomodulation therapy (PBMT) using 660 nm phototherapy in a rat model with lipopolysaccharide (LPS)-induced neuroinflammation. Methods: We induced inflammation in rat brains via intraperitoneal injection of LPS and subjected the treatment group to 660 nm phototherapy to examine its protective effect against hippocampal damage based on pathological, histological, and immunohistochemical tissue analyses. Results: The 660 nm treated rats showed a significant decrease in hippocampal structural damage and cell death compared to the LPS-treated group. We observed reduced expression of the inflammation markers GFAP, TNF-α, and IL-1β in the hippocampus of the treatment group, and an increase in SIRT1 expression across all hippocampal regions. Conclusions: This study presents a promising method for controlling neuroinflammation and providing neuroprotection and inflammation relief. PBMT represents a non-invasive therapeutic approach with minimal side effects ensured through the proper control of light irradiation.

Inulin alleviates inflammatory response and gut barrier dysfunction via modulating microbiota in lipopolysaccharide-challenged broilers

This study was conducted to explore the protective effects of inulin against lipopolysaccharide (LPS)-induced inflammatory response and intestinal barrier dysfunction in broilers. 108 broilers were allocated to 3 treatments: 1) non-challenged broilers (Control, CON); 2) LPS-challenged broilers (LPS); 3) LPS-challenged broilers fed the basal diet supplemented with 15 g/kg of inulin (Inulin+LPS). At 21 d of age, the LPS-challenged groups received an intraperitoneal injection of LPS, and the CON group received an equal volume of saline. After 4 h of LPS exposure, samples of blood, intestinal mucosa and cecal digesta were collected. The results showed that LPS challenge induced systemic inflammation and damaged intestinal barrier function, whereas inulin attenuated LPS-induced production of pro-inflammatory cytokines by inhibiting the activation of TLR4 and NF-κB p65, and enhanced intestinal barrier function. In addition, LPS stimulation caused cecal microbial dysbiosis as shown by increased abundance of pathogenic bacteria including Ruminococcus_torques_group, Escherichia-Shigella and Subdoligranulum, while supplementation of inulin increased abundance of beneficial bacteria Faecalibacterium and Anaeroplasma, and metabolite production including propionate and butyrate concentrations. In conclusion, dietary supplementation of inulin could partially alleviate LPS-induced inflammation and intestinal barrier injury by modulating intestinal microbiota, thereby minimizing growth retardation of broilers. Our results provide a basis for the rational utilization of inulin in alleviating immune stress in broiler production.

Protective effect of 6'-Sialyllactose on LPS-induced macrophage inflammation via regulating Nrf2-mediated oxidative stress and inflammatory signaling pathways.

Macrophages play a central role in cardiovascular diseases, like atherosclerosis, by accumulating in vessel walls and inducing sustained local inflammation marked by the release of chemokines, cytokines, and matrix-degrading enzymes. Recent studies indicate that 6'-sialyllactose (6'-SL) may mitigate inflammation by modulating the immune system. Here, we examined the impact of 6'-SL on lipopolysaccharide (LPS)-induced acute inflammation using RAW 264.7 cells and a mouse model. In vivo, ICR mice received pretreatment with 100 mg/kg 6'-SL for 2 h, followed by intraperitoneal LPS injection (10 mg/kg) for 6 h. In vitro, RAW 264.7 cells were preincubated with 6'-SL before LPS stimulation. Mechanistic insights were gained though Western blotting, qRT-PCR, and immunofluorescence analysis, while reactive oxygen species (ROS) production was assessed via DHE assay. 6'-SL effectively attenuated LPS-induced p38 MAPK and Akt phosphorylation, as well as p65 nuclear translocation. Additionally, 6'-SL inhibited LPS-induced expression of tissue damage marker MMP9, IL-1β, and MCP-1 by modulating NF-κB activation. It also reduced ROS levels, mediated by p38 MAPK and Akt pathways. Moreover, 6'-SL restored LPS-suppressed Nrf2 and HO-1 akin to specific inhibitors SB203580 and LY294002. Consistent with in vitro results, 6'-SL decreased oxidative stress, MMP9, and MCP-1 expression in mouse endothelium following LPS-induced macrophage activation. In summary, our findings suggest that 6'-SL holds promise in mitigating atherosclerosis by dampening LPS-induced acute macrophage inflammation.

Cordycepin Alleviates Lipopolysaccharides-Induced Preeclampsia-Like Impairments in Rats

ABSTRACT Introduction Preeclampsia is a serious pregnancy complication that can lead to life-threatening conditions such as seizures, strokes, and even death. A dysregulated inflammatory response in the placenta plays a crucial role in the development of preeclampsia. Cordycepin, known for its anti-inflammatory and antioxidant properties, was the focus of this study, which aimed to investigate its effects on preeclampsia. Methods A preeclampsia-like rat model was established via tail vein injection of lipopolysaccharides (LPS) at a dose of 1 μg/kg in pregnant rats. These rats were then treated with cordycepin at doses of 5, 25, or 50 mg/kg from embryonic day 6 (E6) today 18 (E18). Systolic blood pressures and urinary protein levels were monitored, and pregnancy outcomes, such as fetal body length and weight, were measured. The expression of target genes or proteins was assessed by qPCR, ELISA, and Western blot. Results Our findings revealed that cordycepin significantly reduced systolic blood pressure and proteinuria in preeclampsia-like rats. Additionally, cordycepin improved pregnancy outcomes, as shown by increased fetal body length and weight. The treatment also lowered serum sFlt-1 levels, elevated PIGF levels, decreased placental pro-inflammatory cytokine levels (IL-1β, TNF-α, IL-6, MCP-1, and MIP-2), and raised levels of anti-inflammatory cytokine IL-10 level in preeclampsia-like rats. Furthermore, cordycepin helped restore macrophage population imbalances, increasing M1-type macrophage markers (iNOS, TNF-α, and IL-1β) and reducing M2-type macrophage markers (Arg 1, IL-10, and TGF-β). Conclusion This study suggests that cordycepin alleviates LPS-induced preeclampsia by reducing placental inflammation and correcting the M1/M2 macrophage imbalance, offering potential therapeutic benefits for managing preeclampsia.

Delayed effects of antibiotic therapy in endotoxinemia

BACKGROUND: Nowadays, due to the increasing number of infectious and inflammatory diseases, the problem of the use of antibacterial drugs becomes especially important. As a result of the action of toxins, inflammatory processes can affect the central nervous system with the subsequent development of neuroinflammation. Activation of neuroinflammation leads to dysregulation of many physiological functions. These negative appearances can be observed even after a long period. It is known that doxycycline is a tetracycline-type antibiotic, which is able to penetrate the blood-brain barrier and has anti-inflammatory activity. AIM: The aim of this study was to investigate the nature of delayed physiological changes in rats against the background of administration of the antibacterial drug doxycycline in the LPS-induced model of neuroinflammation. MATERIALS AND METHODS: Four groups of Wistar rats, 10 males in each group, were used in the experiment. The first group was injected once intraperitoneally with physiological solution, the second group — with lipopolysaccharide (1 mg/kg). Animals of the third and fourth groups received intragastrically doxycycline solution (25 mg/kg) daily for two weeks. On the 15th day of the experiment, rats from the fourth group were injected with lipopolysaccharide (1 mg/kg). Body weight of animals, mass coefficients of immunocompetent organs, as well as behaviour and motor activity of rats in the “Open Field” test were evaluated at several time points. RESULTS: It was shown that systemic injection of lipopolysaccharide led to an increase in the mass coefficients of spleen, kidneys and adrenal glands compared to the group of animals receiving doxycycline beforehand. These changes were noted 48 h and 2 months after the injection of endotoxin. In the “Open Field” test, animals that were injected with doxycycline and lipopolysaccharide showed no violations of motor activity and research behavior, unlike the group that received only lipopolysaccharide. CONCLUSIONS: It can be assumed that the physiological effects of doxycycline in the lipopolysaccharide-induced model of neuroinflammation revealed at early and late terms are not limited to the antibacterial effect of the drug and are mediated by anti-inflammatory and potential neuroprotective effects on the central nervous system.

Influence of Acute Inflammation on the Expression of Clock Genes in the Ovine Pars Tuberalis Under Different Photoperiodic Conditions

The pars tuberalis (PT) plays an important role in the photoperiodic regulation of the secretory activity of the pituitary gland. Additionally, PT secretory activity may be influenced by the animal’s immune status. The melatonin signal processing in PT cells occurs through the presence of melatonin receptors and the expression of molecular clock genes. This study aimed to define the effects of acute inflammation induced by intravenous administration of lipopolysaccharide (LPS) on the expression of clock genes in the PT of ewes under different photoperiodic conditions. Two analogous experiments were conducted in different photoperiods: short-day and long-day. Both experiments included 24 sheep divided into two groups: day (n = 12) and night (n = 12), further subdivided into a control group (n = 6) and a group treated with LPS (n = 6) at a dose of 400 ng/kg. Under short-day conditions, the expression of clock circadian regulator, basic helix-loop-helix ARNT like 1, cryptochrome circadian regulator (CRY) 1, 2, and casein kinase 1 epsilon genes was lower during inflammation. LPS injection increased expression of the period circadian regulator 1 gene during the night. Under long-day conditions, CRY1 mRNA level was lower during the night, while diurnal CRY2 mRNA expression was decreased after LPS injection. Our results showed that inflammation disturbed the expression of molecular clock genes in the PT; however, this influence was partly dependent on photoperiod conditions.

Analysis of correlations between behavioral parameters in the elevated plus maze and the levels of interleukin-1beta in blood plasma in rats

Peripheral cytokines may influence psychoemotional behavior, but the role of interleukin-1beta (IL-1beta) in altering anxiety and motor activity in response to inflammatory activation remains unclear. To clarify this issue, correlations between behavioral parameters in the elevated plus maze (EPM) test and plasma levels of IL-1beta after administration of the proinflammatory stimulus lipopolysaccharide (LPS) in different modes were analyzed in adult male rats. LPS in doses of 0.5 or 5 mg/kg, as well as physiological solution (control), were administered to rats intraperitoneally. The most pronounced behavioral effect 24 hours after a single injection was an endotoxin dose-dependent inhibition of the animals’ motor activity. After a dose of 5 mg/kg, increased anxious behavior was also noted every other day. The behavioral changes caused by the high dose of endotoxin were completely normalized after a week. The behavior of the animals one day after the end of repeated injections of LPS at a lower dose for a week (0.5 mg/kg; once every two days) also did not differ from the control. The inhibition of motor activity after LPS could be due to an increase in the level of IL-1beta in the blood plasma, as indicated by the identified significant negative correlations between IL-1beta and the corresponding behavioral parameters. No significant correlation was found between the peripheral level of IL-1beta and such a classic indicator of anxiety as the percentage of entries into the open arms of the maze. In general, the obtained results allow us to conclude that IL-1beta is an undoubted participant in the mechanism of the transient inhibitory effect of LPS on motor activity.

Lactobacillus reuteri or Lactobacillus rhamnosus GG intervention facilitates gut barrier function, decreases corticosterone and ameliorates social behavior in LPS-exposed offspring

Probiotic therapy with Lactobacillus reuteri and Lactobacillus rhamnosus (LGG) demonstrates potential as an adjunctive treatment for autism spectrum disorder (ASD). In a rat model of ASD induced by lipopolysaccharide (LPS) injection during pregnancy, we evaluated the effects of these probiotics on offspring. Administration of L. reuteri or LGG for three weeks post-birth improved social deficits and reduced anxiety in LPS-exposed rats. Additionally, probiotics significantly modified short-chain fatty acid profiles, increasing butyric acid levels and decreasing propionic acid levels. They also enhanced colonic barrier integrity by upregulating tight junction proteins, including ZO-1, Occludin, and Claudin4. RNA sequencing identified differential gene expression in pathways related to inflammation, the HPA axis, and reactive oxygen species metabolism, with NADPH oxidase 1 (NOX1) emerging as a crucial gene. Validation studies confirmed that Lactobacillus strains reduced inflammatory cytokines, inhibited corticosterone secretion, increased antioxidant levels, and suppressed the NF-κB/NOX1 pathway. In an H2O2-induced oxidative stress model using Caco-2 cells, pre-treatment with L. reuteri, LGG, or NF-κB inhibitors enhanced cellular antioxidants, inhibited NF-κB/NOX1 activation, and improved barrier function. Overall, L. reuteri and LGG administration improved social behavior, bolstered colonic barrier function, and mitigated HPA axis overactivation in LPS-exposed rats, while also alleviating oxidative stress in the colon and Caco-2 cells. These findings suggest that L. reuteri and LGG have substantial clinical potential for ASD treatment by targeting multiple pathophysiological mechanisms, including inflammation, HPA axis dysregulation, and oxidative stress, thereby presenting a promising adjunctive therapeutic strategy for enhancing social behavior and gut health in ASD.

Compromised endothelial Wnt/β-catenin signaling mediates the blood-brain barrier disruption and leads to neuroinflammation in endotoxemia.

The blood-brain barrier (BBB) is a critical interface that maintains the central nervous system homeostasis by controlling the exchange of substances between the blood and the brain. Disruption of the BBB plays a vital role in the development of neuroinflammation and neurological dysfunction in sepsis, but the mechanisms by which the BBB becomes disrupted during sepsis are not well understood. Here, we induced endotoxemia, a major type of sepsis, in mice by intraperitoneal injection of lipopolysaccharide (LPS). LPS acutely increased BBB permeability, activated microglia, and heightened inflammatory responses in brain endothelium and parenchyma. Concurrently, LPS or proinflammatory cytokines activated the NF-κB pathway, inhibiting Wnt/β-catenin signaling in brain endothelial cells in vitro and in vivo. Cell culture study revealed that NF-κB p65 directly interacted with β-catenin to suppress Wnt/β-catenin signaling. Pharmacological NF-κB pathway inhibition restored brain endothelial Wnt/β-catenin signaling activity and mitigated BBB disruption and neuroinflammation in septic mice. Furthermore, genetic or pharmacological activation of brain endothelial Wnt/β-catenin signaling substantially alleviated LPS-induced BBB leakage and neuroinflammation, while endothelial conditional ablation of the Wnt7a/7b co-receptor Gpr124 exacerbated the BBB leakage caused by LPS. Mechanistically, Wnt/β-catenin signaling activation rectified the reduced expression levels of tight junction protein ZO-1 and transcytosis suppressor Mfsd2a in brain endothelial cells of mice with endotoxemia, inhibiting both paracellular and transcellular permeability of the BBB. Our findings demonstrate that endotoxemia-associated systemic inflammation decreases endothelial Wnt/β-catenin signaling through activating NF-κB pathway, resulting in acute BBB disruption and neuroinflammation. Targeting the endothelial Wnt/β-catenin signaling may offer a promising therapeutic strategy for preserving BBB integrity and treating neurological dysfunction in sepsis.

Experimental peri-implantitis induces neuroinflammation: An exploratory study in rats

PurposeCumulating evidence supports the close association between periodontal diseases, neuroinflammation and neurodegenerative pathologies, except for peri-implantitis (PI). Thus, this study explored the association between experimental PI and neuropathological changes in the rat brain.Materials and methodsAfter bilateral first molars extraction, experimental PI was induced at titanium implants placed in the maxillae by lipopolysaccharide injections and ligature placement. Following 28-weeks of disease progression, the maxillae and brains were retrieved from 6 rats. Healthy brains from 3 rats were used as control. Brains were analyzed by immunohistochemistry to detect signs of neuroinflammation (interleukin (IL)-6 and tumor necrosis factor (TNF)-α)), microglial activation (IBA-1) and astrogliosis (GFAP). To explore signs of neurodegeneration, hematoxylin/eosin and Nissl stainings were used. Also, four different antibodies against amyloid beta (Aβ 1–42) were tested.ResultsChronic PI lesions showed peri-implant bone resorption accompanied by large inflammatory infiltrates. IL-6+ and TNF-α+ cells were found within the CA1 and Dentate Gyrus regions of the hippocampus of the PI-affected group, while almost no immune-positivity was detected in the control (p < 0.05). Detection of activated GFAP+ microglia and IBA-1+ astrocytes surface were significantly higher at the CA areas, and cerebral cortex of the PI-affected group, in comparison with control (p < 0.05). Shrunk neurons with pyknotic nuclei were inconsistently found among the PI-affected group, and these were almost not detected in control. No positive Aβ reactivity was detected in any of the samples.ConclusionChronic experimental PI lesions led to an increased detection of IL-6 and TNF-α, GFAP+ microgliosis and IBA-1+ astrocytosis, and in some cases, neurodegeneration, in the rat brain.

Integrated temporal transcriptional and epigenetic single-cell analysis reveals the intrarenal immune characteristics in an early-stage model of IgA nephropathy during its acute injury.

Kidney inflammation plays a crucial role in the pathogenesis of IgA nephropathy (IgAN), yet the specific phenotypes of immune cells involved in disease progression remain incompletely understood. Utilizing joint profiling through longitudinal single-cell RNA-sequencing (scRNAseq) and single-cell assay for transposase-accessible chromatin sequencing (scATACseq) can provide a comprehensive framework for elucidating the development of cell subset diversity and how chromatin accessibility regulates transcription. We aimed to characterize the dynamic immune cellular landscape at a high resolution in an early IgAN mouse model with acute kidney injury (AKI). A murine model was utilized to mimic 3 immunological states -"immune stability (IS), immune activation (IA) and immune remission (IR)" in early human IgAN-associated glomerulopathy during AKI, achieved through lipopolysaccharide (LPS) injection. Urinary albumin to creatinine ratio (UACR) was measured to further validate the exacerbation and resolution of kidney inflammation during this course. Paired scRNAseq and scATACseq analysis was performed on CD45+ immune cells isolated from kidney tissues obtained from CTRL (healthy vehicle), IS, IA and IR (4 or 5 mice each). The analyses revealed 7 major cell types and 24 clusters based on 72304 single-cell transcriptomes, allowing for the identification and characterization of various immune cell types within each cluster. Our data offer an impartial depiction of the immunological characteristics, as the proportions of immune cell types fluctuated throughout different stages of the disease. Specifically, these analyses also revealed novel subpopulations, such as a macrophage subset (Nlrp1b Mac) with distinct epigenetic features and a unique transcription factor motif profile, potentially exerting immunoregulatory effects, as well as an early subset of Tex distinguished by their effector and cytolytic potential (CX3CR1-transTeff). Furthermore, in order to investigate the potential interaction between immune cells and renal resident cells, we conducted single-cell RNA sequencing on kidney cells obtained from a separate cohort of IS and IA mice without isolating immune cells. These findings underscored the diverse roles played by macrophages and CD8+ T cells in maintaining homeostasis of endothelial cells (ECs) under stress. This study presents a comprehensive analysis of the dynamic changes in immune cell profiles in a model of IgAN, identifying key cell types and their roles and interactions. These findings significantly contribute to the understanding of the pathogenesis of IgAN and may provide potential targets for therapeutic intervention.

The Role of Autophagy on Osteogenesis of Dental Follicle Cells Under Inflammatory Microenvironment.

This study investigated the role of autophagy on osteogenesis of DFCs under inflammatory microenvironment during tooth eruption. DFCs were isolated and identified. Lipopolysaccharide (LPS) was used to construct the inflammatory microenvironment invitro and invivo. Cell viability was examined by CCK-8 assay. Osteogenic differentiation was evaluated by alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining. The gene and protein levels were examined using qRT-PCR and western blot analysis, respectively. We observed the process of tooth eruption after local LPS injection by micro-CT and HE staining. Osteogenesis and autophagy were monitored through qRT-PCR, western blot and histological staining of specific markers. LPS at the indicated concentrations did not produce toxic effects on DFCs, and significantly promoted the inflammatory gene expression. LPS inhibited osteogenic differentiation and activated autophagy in DFCs. Blocking autophagy with 3-MA reversed the expression of osteogenic markers in LPS-treated DFCs. Additionally, the eruption of LPS-treated teeth was accelerated and their DFs exhibited an increased expression of TNF-α and Beclin1, and decreased expression of ALP and RUNX2. Autophagy was involved in the suppression of the DFCs osteogenesis in an LPS-induced inflammatory condition, suggesting the pivotal role of autophagy in inflammation-induced premature tooth eruption.

Heme Oxygenase-1 Protected Against Severe Acute Pancreatitis by Inhibiting Inflammatory Response

Abstract Background Activation of NLPR3 inflammasome promotes the maturation and secretion of IL-1β and IL-18, leading to a series of inflammatory reactions, while inhibition of NLRP3 inflammasome alleviates the severity of Severe Acute Pancreatitis (SAP). An inducible enzyme responsible for heme decomposition, heme oxygenase-1 (HO-1), has anti-inflammatory, antioxidant, and anti-proliferative effects. HO-1 activity profoundly affects the host ability to forbear infection by reducing tissue damage or affecting resistance and increasing the capacity to pathogen load. We postulated that hemin, a strong HO-1 inducer, could decrease NLRP3 inflammasome activation, which would alleviate the severity of SAP and acute lung injury caused by pancreatitis. Methods By administering intraperitoneal injections of caerulein (Cae) and lipopolysaccharide (LPS), the SAP rat model was created. Then, the SAP rats were pretreated with Hemin or zinc protoporphyrin IX (Znpp, a HO-1 inhibitor) to stimulate or inhibit the HO-1 enzyme respectively, and the effects and mechanisms were investigated. Results The pancreas and lung tissue of the SAP rats suffered considerable pathological damage after Cae and LPS injection, with significant increases of amylase, lipase, IL-1β and IL-18 levels in the serum. Hemin pretreatment decreased IL-1β and IL-18 release in the serum and prevented pancreatic and pulmonary damage. Hemin dramatically reduced oxidative stress, downregulated the expression of NLRP3, ASC, and Caspase-1, and elevated HO-1 expression. On the contrary, there were no discernible changes between the SAP control and Znpp treated groups. Conclusion These results showed that hemin prevented Cae and LPS-induced lung and pancreatic injury through suppression of the inflammatory response. The impact of hemin on the activity of the NLRP3 inflammasome was depending critically on HO-1 activity. The protective role and mechanism HO-1 against the acute and severe inflammatory responses may provide a novel and effective therapeutic approach for SAP treatment.

Novel TSPO Ligand 2-Cl-MGV-1 Can Counteract Lipopolysaccharide Induced Inflammatory Response in Murine RAW264.7 Macrophage Cell Line and Lung Models.

We assessed the anti-inflammatory activity of the TSPO ligand 2-Cl-MGV-1. Lipopolysaccharide (LPS) was used to induce inflammatory response in a murine RAW264.7 macrophage model (LPS: 100 ng/mL) and a mouse model (C57BL/6) of lung inflammation (LPS: 5 mg/kg). In the macrophage model, the presence of 2-Cl-MGV-1 (25 µM) caused the LPS-induced elevation in nitrite levels to decrease by 70% (p < 0.0001) and interleukin (IL)-6 by 50% (p < 0.05). In the mouse model, 2-Cl-MGV-1, administered 30 min before, or co-administered with, an LPS injection, significantly inhibited the elevation in serum IL-5 levels (both by 65%; p < 0.001 and p < 0.01, respectively). 2-Cl-MGV-1 administration to mice 30 min before LPS injection and 1 h thereafter significantly inhibited the elevation in IL-1β serum levels (both by 63%, p < 0.005). IL-6 elevation was inhibited by 73% (p < 0.005) when 2-Cl-MGV-1 was administered 30 min before LPS, by 60% (p < 0.05) when co-administered with LPS, and by 64% (p < 0.05) when administered 1 h after LPS. All cytokine assessments were conducted 6 h post LPS injection. Histological analyses showed decreased leukocyte adherence in the lung tissue of the ligand-treated mice. 2-Cl-MGV-1 administration 30 min prior to exposure to LPS inhibited inflammation-induced open field immobility. The beneficial effect of 2-Cl-MGV-1 suggests its potential as a therapeutic option for inflammatory diseases.

Inhalation of H2/O2 (66.7 %/33.3 %) mitigates depression-like behaviors in diabetes mellitus complicated with depression mice via suppressing inflammation and preventing hippocampal damage

Diabetes mellitus complicated with depression (DD) is a prevalent psychosomatic disorder. It is characterized by severe cognitive impairment, and associated with high rates of disability and mortality. Although conventional treatment options are available, the efficacy of these regimens in managing DD remains limited. Molecular hydrogen (H2), a selective hydroxyl radical scavenger, has shown therapeutic potential in the treatment of various systemic diseases. This study aims to investigate the therapeutic effects of H2 on DD. A DD mouse model was established through intraperitoneal injection of streptozotocin (STZ, 150 mg/kg) and lipopolysaccharide (LPS, 0.5 mg/kg). Following the induction of DD, the mice were treated with H2/O2 (66.7 %/33.3 %)inhalation for 7 days. Behavioral assessments were conducted by standard behavioral tests, and the levels of inflammatory cytokines in peripheral blood serum and hippocampal tissue were measured using enzyme-linked immunosorbent assay (ELISA). Furthermore, magnetic resonance imaging (MRI) scans and immunofluorescence staining of the hippocampus were performed to evaluate hippocampal structural integrity. The results demonstrated that inhalation of H2/O2 (66.7 %/33.3 %) significantly ameliorated depressive behaviors and symptoms in DD mice, reversed hippocampal volume reduction, decreased inflammatory cytokine levels in peripheral blood serum and hippocampal tissue, and inhibited the activation of A1 astrocytes in the hippocampus. Our study suggests that H2/O2 (66.7 %/33.3 %) inhalation therapy may offer a promising treatment strategy for DD and its associated symptoms.

12207 A Two-hit Model Of Pcb Exposure And Immune Challenge, And Effects On Behaviors In Rats

Abstract Disclosure: S.E. Khoury: None. A. Hynes: None. L.K. Davis: None. L. Thompson: None. K. Sanchez: None. L. Fonken: None. A.C. Gore: None. This study evaluated how two common life experiences: exposures to environmental endocrine-disrupting chemicals (EDCs), and immune challenges, can act independently or in combination to affect social and anxiety-like behaviors in rats. The class of endocrine-disrupting chemical (EDC) used was polychlorinated biphenyls (PCBs), a family of industrial chemicals that, despite their ban in the 1970s, are detectable in the body tissues of virtually all humans and animals today due to their persistence. Exposures to PCBs were given prenatally and in early postnatal life through feeding of rat dams, during hormone sensitive periods of brain development in the offspring. The immune challenge was given postnatally during adolescence through injection of lipopolysaccharide, to induce neuroinflammation. These challenges are individually associated with increased behavioral disorders in humans and rodent models, but how they interact is unknown. In this 2x2 design, rats received either PCBs or oil in early life, and LPS or saline in adolescence. The animals were then tested in a series of behavioral assays to assess for social and anxiety-like behaviors, including Open Field (OF), Juvenile Social Exploration (JSE), Three Chamber Social Test (TCST), Light Dark Box (LD), and Elevated Plus Maze (EPM). An effect of PCB was observed in OF center time. Interactions of EDC and LPS were found in aspects of EP, and TCST. Further work examining protein and gene expression in the hippocampus and hypothalamus is in progress and will help to elucidate the underlying biological mechanism of the observed behavioral changes. Presentation: 6/3/2024

Dietary astragalin confers protection against lipopolysaccharide-induced intestinal mucosal barrier damage through mitigating inflammation and modulating intestinal microbiota.

The intestinal mucosal barrier (IMB) damage is intricately linked with the onset of numerous intestinal diseases. Astragalin (AS), a flavonoid present in numerous edible plants, exhibits notable antioxidant and anti-inflammatory properties, demonstrating a promising impact on certain intestinal ailments. In this study, our objective was to investigate the protective effects of AS and elucidate the underlying mechanisms by which it mitigates lipopolysaccharide (LPS)-induced damage to the IMB in mice. During the experimental period, mice were subjected to a 7-day regimen of AS treatment, followed by LPS injection to induce IMB damage. Subsequently, a comprehensive evaluation of relevant biological indicators was conducted, including intestinal pathological analysis, serum inflammatory factors, intestinal tight junction proteins, and intestinal microbiota composition. Our results suggested that AS treatment significantly bolstered IMB function. This was evidenced by the enhanced morphology of the small intestine and the elevated expression of tight junction proteins, including ZO-1 and Claudin-1, in addition to increased levels of MUC2 mucin. Moreover, the administration of AS demonstrated a mitigating effect on intestinal inflammation, as indicated by the reduced plasma concentrations of pro-inflammatory cytokines such as IL-6, IL-1β, and TNF-α. Furthermore, AS treatment exerted a positive influence on the composition of the gut microbiota, primarily by augmenting the relative abundance of beneficial bacteria (including Lachnospiracea and Lactobacillus murinus), while simultaneously reducing the prevalence of the harmful bacterium Mucispirillum schaedleri. AS mitigates LPS-induced IMB damage via mitigating inflammation and modulating intestinal microbiota.