Single Dose Of Lipopolysaccharide Research Articles

CAPE ameliorates vascular damage caused by sepsis

parameters of vascular and oxidative damage caused by sepsis and to evaluated the effects of caffeic acid phenethyl ester (CAPE) on these damages.
 Materials and Methods: Wistar-Albino male rats were used for this study. Rats were divided into 4 groups (n = 10). Group 1 animals were intraperitoneally (i.p) injected with sterile saline (Control Group). Group 2 animals were i.p injected with lipopolysaccharide (LPS), 20 mg / kg-weight dose (Sepsis Group). Group 3 animals were i.p injected with lipopolysaccharide, 20 mg / kg-weight dose. Immediately after LPS injection, CAPE was i.p injected at single dose, 10 µmol / kg-body weight (Treatment Group). A single dose of CAPE, 10 µmol / kg-body weight / day, was injected i.p to Group 4 animals for 5 days. After 5th day CAPE injection, a single dose of LPS 20 mg / kg-weight was injected (Protective Group). At the 6th hour after the injections applied to all groups, blood sample were taken intracardiac and their serum were separated for the studies. Homocysteine (Hcy), asymmetric dimethyl arginine (ADMA), endothelin-1 (ET-1) and vascular cellular adhesion molecule-1 (VCAM-1) were measured by enzyme-linked immunosorbent assay (ELISA). In addition, the protective and therapeutic effects of CAPE on these parameters was investigated.
 Results: Control group Hcy, ADMA, ET-1 and VCAM-1 levels were found to be 4.987 ± 0.096 µmol/l, 0.803 ± 0.020 nmol/ml, 21.123 ± 2.575 ng/l, 3.155 ± 0.078 ng/ml, respectively. Sepsis group Hcy, ADMA, ET-1 and VCAM-1 levels were found to be 8.975 ± 0.160 µmol/l, 3.953 ± 0.678 nmol/ml, 52.446 ± 2.546 ng/l, 10.783 ± 1.068 ng/ml, respectively. Treatment group Hcy, ADMA, ET-1 and VCAM-1 levels were found to be 5.286 ± 0.037 µmol/l, 1.304 ± 0.040 nmol/ml, 27.995 ± 1.299 ng/l, 3.72 ± 0.073 ng/ml, respectively. Protective group Hcy, ADMA, ET-1 and VCAM-1 levels were found to be 5.401 ± 0.042 µmol/l, 1.431 ± 0.056 nmol/ml, 32.708 ± 1.326 ng/l, 4.058 ± 0.069 ng/ml, respectively. It was observed that the Hcy, ADMA, ET-1 and VCAM-1 levels of the sepsis group increased significantly compared to the control group (p0.05). It was observed that CAPE treatment significantly decreased these parameters levels. However, the use of CAPE as a protective was not as effective as its treatment effect.
 Conclusion: Our results demonstrated that sepsis resulted in increase Hcy, ADMA, ET-1, VCAM-1 levels. All these changes indicate that sepsis-mediated vascular damage is increased. Our results demonstrated that CAPE is more effective in preventing sepsis-mediated damages when given as a treatment.

Unraveling the potential of vitamins C and D as adjuvants in depression treatment with escitalopram in an LPS animal model

Depression is linked with oxidative stress and inflammation, where key players include nitric oxide (NO), nuclear factor erythroid 2-related factor 2 (Nrf2), Brain-Derived Neurotrophic Factor (BDNF), and Heme Oxidase-1 (HO-1). Augmenting the efficacy of antidepressants represents a compelling avenue of exploration. We explored the potential of vitamins C and D as adjuncts to escitalopram (Esc) in a lipopolysaccharide (LPS)-induced depression model focusing on the aforementioned biomarkers. Male Swiss albino mice were stratified into distinct groups: control, LPS, LPS + Esc, LPS + Esc + Vit C, LPS + Esc + Vit D, and LPS + Esc + Vit C + Vit D. After a 7-day treatment period, a single LPS dose (2 mg/kg), was administered, followed by comprehensive assessments of behavior and biochemical parameters. Notably, a statistically significant (p < 0.05) alleviation of depressive symptoms was discerned in the Esc + Vit C + Vit D group versus the LPS group, albeit with concomitant pronounced sedation evident in all LPS-treated groups (p < 0.05). Within the cortex, LPS reduced (p < 0.05) the expression levels of NOx, Nrf2, BDNF, and HO-1, with only HO-1 being reinstated to baseline in the LPS + Esc + Vit D and the LPS + Esc + Vit C + Vit D groups. Conversely, the hippocampal NOx, Nrf2, and HO-1 levels remained unaltered following LPS administration. Notably, the combination of Esc, Vit C, and Vit D effectively restored hippocampal BDNF levels, which had been diminished by Esc alone. In conclusion, vitamins C and D enhance the therapeutic effects of escitalopram through a mechanism independent of Nrf2. These findings underscore the imperative need for in-depth investigations.

Assessing the effects of oxytocin in changes of core body temperature during LPS-induced endotoxemia: A novel approach using Extended Poincaré Plot Analysis

Oxytocin has shown cardioprotective effects during inflammation and may modify the core body temperature changes in LPS-induced endotoxemia. Notably, the time series analysis of core body temperature fluctuations may indicate thermoregulation alterations. This study aims to assess the effects of oxytocin on changes in the core body temperature by analyzing the fluctuations of the temperature time series of endotoxemic rats.Twelve hours of continuous core body temperature fluctuations time series were obtained from adult male Dark Agouti rats implanted with a telemetric transmitter under the following treatment: lipopolysaccharide (LPS); oxytocin (O); lipopolysaccharide + oxytocin (LPS + O), and vehicle or control (C). The temperature fluctuations time series were analyzed using the Extended Poincaré Plot Analysis (EPPA), a novel approach for measuring nonlinear features, to compute the autocorrelation by Pearson's correlation coefficient r, the standard deviation perpendicular to the line of identity (SD1), and the standard deviation parallel to the line of identity (SD2).The autocorrelation of the temperature fluctuations assessed by Pearson's coefficient was significantly higher in the LPS group compared to control rats (C). Likewise, the co-administration of oxytocin during endotoxemia (LPS + O) significantly reduced the autocorrelation and increased the short-term variability (SD1) of temperature fluctuations compared to those recorded with a single dose of LPS. Thus, we concluded that oxytocin may introduce thermoregulatory changes under LPS-induced endotoxemia. The EPPA is a simple and powerful approach to assess physiological variability that can provide valuable insights into changes in thermoregulation.

Macrophages derived from LPS-stimulated monocytes from individuals with subclinical atherosclerosis were characterized by increased pro-inflammatory activity

ObjectiveAtherosclerosis is characterized by chronic inflammation in the vascular wall. Currently the violation of immune tolerance of innate immune cells is considered as a possible mechanism of chronification of inflammation. The aim of this study is to assess the inflammatory activity and tolerance of monocytes and macrophages in subclinical atherosclerosis. MethodsA total of 55 individuals free from clinical manifestations of atherosclerosis-associated cardiovascular disease with a presence or absence of atherosclerotic plaques in the carotid arteries were included in this study. CD14+ monocytes were isolated from individuals' blood and stimulated with a single dose of lipopolysaccharide (LPS) on day 1 or with double doses of LPS on day 1 and day 6. The secretion of cytokines TNF, IL-1β, IL-6, IL-8, IL-10 and CCL2 were evaluated using ELISA. ResultsOur findings demonstrate that macrophages derived from LPS-stimulated monocytes in individuals with subclinical atherosclerosis exhibited increased secretion of IL-6, IL-10 and CCL2, which was associated with intima-media thickness, body mass index, but not with individuals’ age. Moreover, macrophages from individuals with atherosclerotic plaques exhibited impaired tolerance towards the second LPS stimulation manifested by elevated secretion of the chemoattractant CCL2. ConclusionIncreased secretion of these cytokines by macrophages may contribute to chronic local inflammation in the vascular wall by recruiting other immune cells.

Melatonin alleviates intrarenal CaOx crystals deposition through inhibiting LPS-induced non-canonical inflammasome-mediated renal tubular epithelial cells pyroptosis

Urinary tract infection has long been considered a complication rather than etiology of calcium oxalate (CaOx) nephrolithiasis. This study aimed to explore the role of lipopolysaccharide (LPS), an important component of Gram-negative bacteria, on CaOx nephrolithiasis formation and antagonistic effect of melatonin. Male C57BL/6 mice were intraperitoneally injected with glyoxylate acid (80 mg/kg) daily for 7 days to construct CaOx nephrolithiasis model. A single dose of LPS (2.0 mg/kg) was given 2 h before the second glyoxylate acid treatment in the presence or absence of melatonin (25 mg/kg). Our results found that LPS promoted adhesion of CaOx crystals to renal tubular epithelial cells (RTECs) and intrarenal CaOx crystals deposition. Protein levels of cleaved Caspase-11, N-terminal of cleaved GSDMD (GSDMD-N), NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and cleaved Caspase-1, several markers of non-classical inflammasome activation were upregulated in LPS-treated mouse kidneys and HK-2 cells. Moreover, the number of GSDMD pores was increased in LPS-treated HK-2 cell membrane. Melatonin inhibited Caspase-11 cleavage and antagonized the subsequent LPS-mediated upregulation of GSDMD-N, NLRP3 and cleaved Caspase-1 in kidney tissues and HK-2 cells. In addition, melatonin reduced membrane localization of GSDMD-N and the number of GSDMD pores in LPS-treated HK-2 cells. Accordingly, melatonin inhibited LPS-induced IL-1β and IL-18 in mouse serum and HK-2 culture supernatant. Importantly, melatonin alleviated LPS-induced crystal-cell interactions and intrarenal CaOx crystals deposition. We provide experimental evidence that LPS promoted CaOx nephrolithiasis formation by inducing non-canonical inflammasome-mediated RTECs pyroptosis. Melatonin alleviated CaOx nephrolithiasis formation through inhibiting LPS-induced non-canonical inflammasome-mediated RTECs pyroptosis.

Protective effects of Centella asiatica extract on spatial memory and learning deficits in animal model of systemic inflammation induced by lipopolysaccharide

Background and aim Centella asiatica (L.) Urb. (Apiaceae) is a renowned medicinal plant being used in the Ayurvedic system for its pharmacological effects on the central nervous system such as rejuvenating, sedative, anxiolytic and memory-enhancing properties. The present study was designed to investigate the effect of Centella asiatica (CA) extract on inflammatory responses induced by lipopolysaccharide (LPS) and resulting changes in cognitive behavior. Materials and methods Adult male Sprague-Dawley rats were divided into 4 groups as control, LPS, CA and LPS + CA. The treatments with LPS (5 mg/kg) were intraperitoneally (i.p) injected on day 4 and CA ethanol extract (200 mg/kg) were given orally for 14 days. Morris Water Maze (MWM) test was performed to assess spatial learning and memory performance. Acute oral toxicity of the extract at the highest dose of 5000 mg/kg was also conducted. Results Single administration of LPS was able to significantly elicit learning and memory impairment (p < .05) when compared to the control groups. Treatment with CA significantly improved the impaired learning ability in which the LPS + CA rats took the shortest time and route to find the hidden platform (15.85 ± 2.68 s (p < .001); 352.43 ± 88.10 cm (p < .001) on day 5) and induced differential cytokine responses in the blood. No mortality and no significant variation in the body and organ weights between the control and the treated group was observed after 14 days of acute toxicity study. Hematological analysis and biochemical parameters revealed no toxic effects of the extract. Pathologically, neither gross abnormalities nor histopathological changes were observed. Discussion and conclusion Centella asiatica extract exhibited significant learning and memory enhancement potential in animal model. Hence, indicating its putative preventive therapeutic effects in neuroinflammation related diseases. KEY MESSAGE A single dose of lipopolysaccharide (LPS) (5 mg/kg) administered systemically to mimic the consequences of LPS-induced inflammatory responses was able to affect some behavioral modification of spatial memory at the time point of study. The study showed that the learning capability during the training trial was restored or ameliorated with the pre-emptive treatment of Centella asiatica extract (200 mg/kg). Centella asiatica extract improves spatial memory, learning deficits and regulates proinflammatory responses in systemic LPS-treated rats.

Less Severe Lipopolysaccharide-Induced Inflammation in Conditional mgmt-Deleted Mice with LysM-Cre System: The Loss of DNA Repair in Macrophages.

Despite the known influence of DNA methylation from lipopolysaccharide (LPS) activation, data on the O6-methylguanine-DNA methyltransferase (MGMT, a DNA suicide repair enzyme) in macrophages is still lacking. The transcriptomic profiling of epigenetic enzymes from wild-type macrophages after single and double LPS stimulation, representing acute inflammation and LPS tolerance, respectively, was performed. Small interfering RNA (siRNA) silencing of mgmt in the macrophage cell line (RAW264.7) and mgmt null (mgmtflox/flox; LysM-Crecre/-) macrophages demonstrated lower secretion of TNF-α and IL-6 and lower expression of pro-inflammatory genes (iNOS and IL-1β) compared with the control. Macrophage injury after a single LPS dose and LPS tolerance was demonstrated by reduced cell viability and increased oxidative stress (dihydroethidium) compared with the activated macrophages from littermate control mice (mgmtflox/flox; LysM-Cre-/-). Additionally, a single LPS dose and LPS tolerance also caused mitochondrial toxicity, as indicated by reduced maximal respiratory capacity (extracellular flux analysis) in the macrophages of both mgmt null and control mice. However, LPS upregulated mgmt only in LPS-tolerant macrophages but not after the single LPS stimulation. In mice, the mgmt null group demonstrated lower serum TNF-α, IL-6, and IL-10 than control mice after either single or double LPS stimulation. Suppressed cytokine production resulting from an absence of mgmt in macrophages caused less severe LPS-induced inflammation but might worsen LPS tolerance.

Curcumin attenuates memory impairments and long-term potentiation deficits by damping hippocampal inflammatory cytokines in lipopolysaccharide-challenged rats.

Neuroinflammation is a key pathological event triggering neurodegenerative process, resulting in neurologic sequelae. Curcumin (cur) has recently received increasing attention due to its anti-inflammatory properties. Therefore, we investigated the protective effects of curcumin on lipopolysaccharide (LPS)-induced memory impairments, long-term potentiation (LTP) deficits, hippocampal inflammatory cytokines, and neuronal loss in male rats. Rats were randomly divided into four groups as follows: (1) Vehicle; (2) cur; (3) LPS; and (4) cur/LPS. Following curcumin pretreatment (50mg/kg, per oral via gavage, 14 consecutive days), animals received a single dose of LPS (1mg/kg, intraperitoneally) or saline. Twenty-four hours after LPS/or saline administration, passive avoidance test (PAT), hippocampal LTP, inflammatory cytokines (TNFα, IL-1β), and neuronal loss were assessed in hippocampal tissue of rats. Our results indicated that pretreatment with curcumin in LPS-challenged rats attenuates memory impairment in PAT, which was accompanied by significant increase in the field excitatory post-synaptic potential (fEPSP) slope and population spike (PS) amplitude. Hence, pretreatment with curcumin in LPS-treated rats decreased hippocampal concentration of tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β), as well as reduced neuronal loss in the hippocampal tissue. This study provide evidence that pretreatment with curcumin attenuates LPS-induced memory impairment and LTP deficiency, which may be partly related to the amelioration of inflammatory cytokines and neuronal loss in the hippocampal tissue.

Liposaccharide-induced sustained mild inflammation fragments social behavior and alters basolateral amygdala activity.

Conditions with sustained low-grade inflammation have high comorbidity with depression and anxiety and are associated with social withdrawal. The basolateral amygdala (BLA) is critical for affective and social behaviors and is sensitive to inflammatory challenges. Large systemic doses of lipopolysaccharide (LPS) initiate peripheral inflammation, increase BLA neuronal activity, and disrupt social and affective measures in rodents. However, LPS doses commonly used in behavioral studies are high enough to evoke sickness syndrome, which can confound interpretation of amygdala-associated behaviors. The objectives of this study were to find a LPS dose that triggers mild peripheral inflammation but not observable sickness syndrome in adult male rats, to test the effects of sustained mild inflammation on BLA and social behaviors. To accomplish this, we administered single doses of LPS (0-100μg/kg, intraperitoneally) and measured open field behavior, or repeated LPS (5μg/kg, 3 consecutive days), and measured BLA neuronal firing, social interaction, and elevated plus maze behavior. Repeated low-dose LPS decreased BLA neuron firing rate but increased the total number of active BLA neurons. Repeated low-dose LPS also caused early disengagement during social bouts and less anogenital investigation and an overall pattern of heightened social caution associated with reduced gain of social familiarity over the course of a social session. These results provide evidence for parallel shifts in social interaction and amygdala activity caused by prolonged mild inflammation. This effect of inflammation may contribute to social symptoms associated with comorbid depression and chronic inflammatory conditions.

Protective efficacy of melatonin and insulin against LPS caused toxicity in diabetic mice

Context: Deregulated glucose homeostasis leads to a life-threatening metabolic disorder known as diabetes. The insulin deficiency and hyperglycaemic condition related to diabetes cause dysregulation of the immune system. Objective: This study evaluated the combined efficacy of melatonin and insulin in attenuation of lipopolysaccharide (LPS) caused inflammation, macrophage functional impairment, and oxidative stress in the spleen of diabetic mice. Materials and Methods: Multiple low doses of streptozotocin (50mg/kg B. wt.) were administered intraperitoneally to induce diabetes. Diabetes mice were divided into two sets. Set-1 contained control, diabetes, diabetes insulin (2IU/100g B.wt.) treated, diabetes melatonin (100µg/100g. B.wt.) treated, and diabetes melatonin and insulin treated groups of mice. In set II, the same number of groups as those of set I were given a single dose of LPS (50µg/mice) 24 hours before euthanization. Results and Discussion: LPS caused a significant increase in oxidative stress, circulatory proinflammatory cytokines, significant suppression of antioxidant defense system, and phagocytic index in diabetic mice. Melatonin and insulin significantly improved the adverse effects caused by LPS treatment in diabetic mice. The present study noted that combined treatment of melatonin and insulin was more effective in attenuating LPS-induced devastating effects in laboratory mice. Conclusions: The present study may suggest a combinatorial approach in the therapeutic use of melatonin and insulin to improve such devastating conditions.

Preventive effects of traditional Chinese medicine formula Huoxiangzhengqi against lipopolysaccharide-induced inflammatory response

BackgroundHuoxiangzhengqi oral liquid (HX), a pharmaceutical product made from traditional Chinese medicine formulas, has been commonly used in household medication for gastrointestinal disorders, but the mode of action remains largely unclear. PurposeThis study aims to investigate whether pretreatment with HX prevents lipopolysaccharide (LPS)-induced adverse effects and the potential mechanisms involved. MethodsSeven-week-old male C57BL/6J mice were orally administered low (1.3 ml/kg) and high doses (2.6 ml/kg) of HX for 7 days, and subsequently subjected to a single dose of LPS at 6 mg/kg. Dexamethasone served as the positive control. Each group had ten animals. ResultsThe data demonstrated that either a low or high dose of HX significantly reduced the levels of inflammation induced by LPS in both small intestinal and cortical tissues. LPS profoundly decreased the richness and evenness of the microbiota and disrupted the composition of the intestinal microbial community, but pretreatment with HX did not successfully prevent dysbiosis. No significant improvements in HX against LPS were observed in intestinal local immunity or the secretion of partial gut-brain peptides. In addition, pretreatment with HX prevented the alterations in the expression levels of proteins related to the NF-κB pathway, including phospho-p38, p38, phospho-p44/42, p44/42, p50 and p65 induced by LPS. ConclusionHerein, we demonstrated for the first time that the preventive effects of HX against LPS mainly occur through the inhibition of inflammation. These findings provide novel evidence that HX may serve as a new agent for the prevention of gastrointestinal inflammation-related disorders.

Ginsenoside Rb1 attenuates lipopolysaccharide-induced neural damage in the brain of mice via regulating the dysfunction of microglia and astrocytes.

The purpose of our research was to evaluate whether ginsenoside Rb1 has neuroprotective effects against lipopolysaccharide (LPS)-induced brain injury. ICR mice were intraperitoneally (i.p.) injected with 20 or 40 mg/kg Rb1 or saline for 7 consecutive days. On the 7th day, 30 minutes after Rb1 or saline administration, a single dose of LPS (LPS group, Rb1+LPS group) or saline (control group) was injected i.p. into the mice. Results demonstrated that Rb1 treatment could significantly improve the behavior performance of LPS mice in both the open field test and the beam walking test. Rb1 can also markedly attenuate the neuronal lesion in both hippocampus and somatosensory cortex in the brain of LPS mice. In addition, Rb1 treatment also significantly inhibits the LPS-induced neuroinflammation in the brain, indicated by reduced reactive microglia and decreased IL-1β production. Both immunostaining and western blot results suggest that Rb1 can further enhance the LPS-induced GLT-1 expression and alleviate LPS-induced GS reduction in the brain. Our findings show that Rb1 has a protective effect on LPS-induced neuronal damage in the CA1 of the hippocampus and in the somatosensory area of the cerebral cortex in mice, which is likely to be the basis for its improvement of locomotor and motor coordination. Rb1 regulating the function of astrocytes and microglia through GLT-1 and GS in astrocytes may be involved in its neuroprotective effects.

Artesunate strongly modulates myeloid and regulatory T cells to prevent LPS-induced systemic inflammation

Lipopolysaccharide (LPS) is the major component of the outer membrane of Gram-negative bacteria and is usually administrated to establish models of inflammation. Artesunate (ART), a water-soluble artemisinin derivative, displays multiple pharmacological actions against tumors, viral infections, and inflammation, and has been used as a therapeutic weapon against malaria. In this study, our aim was to evaluate whether ART pretreatment is capable of preventing inflammation induced by LPS. BALB/c mice were treated with 100 mg/kg of ART i.p. for 7 days followed by a single dose of LPS. ART pretreatment led to an improvement in clinical score, prevented alterations in biochemical markers, and reestablished the platelet counts. Flow cytometry analysis showed that ART protected the inflammation mainly by reducing the percentage of M1 macrophages while increasing M2 macrophages and a reestablishment of classical monocytes in the BM. In the spleen, ART pretreatment increased N2 neutrophils, myeloid-derived suppressor cells (MDSC), and regulatory T cells, the latter was also increased in peripheral blood. In addition, a marked decrease in inflammatory cytokines and chemokines was observed in the ART treated group. Our data suggest that ART prevents inflammation, reducing tissue damage and restoring homeostasis.

Knockout of NPFFR2 Prevents LPS-Induced Depressive-Like Responses in Mice.

The precise neural mechanisms underlying the pathogenesis of depression are largely unknown, though stress-induced brain inflammation and serotonergic plasticity are thought to be centrally involved. Moreover, we previously demonstrated that neuropeptide FF receptor 2 (NPFFR2) overexpression provokes depressive-like behaviors in mice. Here, we assess whether NPFFR2 is involved in priming of depressive-like behaviors and downregulation of serotonergic 1A receptor (5HT1AR) after lipopolysaccharide (LPS) treatment. The forced swimming test (FST) and sucrose preference test (SPT) were used to quantify depressive-like phenotypes in wild-type (WT) and NPFFR2-knockout (KO) mice. A single dose of LPS (i.p. 1 mg/kg) readily caused increases in toll-like receptor 4 and tumor necrosis factor-α along with decreases in 5-HT1AR mRNA in the ventral hippocampus of WT mice. Furthermore, LPS treatment of WT mice increased immobility time in FST and decreased sucrose preference in SPT. In contrast, none of these effects were observed in NPFFR2-KO mice. While WT mice injected with lentiviral 5-HT1AR shRNA in the ventral hippocampus displayed an unaltered response after LPS challenge, LPS-challenged NPFFR2-KO mice displayed a profound decrease in sucrose preference when pretreated with 5-HT1AR shRNA. Taken together, these results suggest that NPFFR2 modulates LPS-induced depressive-like behavioral phenotypes by downregulating 5HT1AR in the ventral hippocampus.

A systemic immune challenge to model hospital-acquired infections independently regulates immune responses after pediatric traumatic brain injury

BackgroundTraumatic brain injury (TBI) is a major cause of disability in young children, yet the factors contributing to poor outcomes in this population are not well understood. TBI patients are highly susceptible to nosocomial infections, which are mostly acquired within the first week of hospitalization, and such infections may modify TBI pathobiology and recovery. In this study, we hypothesized that a peripheral immune challenge such as lipopolysaccharide (LPS)—mimicking a hospital-acquired infection—would worsen outcomes after experimental pediatric TBI, by perpetuating the inflammatory immune response.MethodsThree-week-old male mice received either a moderate controlled cortical impact or sham surgery, followed by a single LPS dose (1 mg/kg i.p.) or vehicle (0.9% saline) at 4 days post-surgery, then analysis at 5 or 8 days post-injury (i.e., 1 or 4 days post-LPS).ResultsLPS-treated mice exhibited a time-dependent reduction in general activity and social investigation, and increased anxiety, alongside substantial body weight loss, indicating transient sickness behaviors. Spleen-to-body weight ratios were also increased in LPS-treated mice, indicative of persistent activation of adaptive immunity at 4 days post-LPS. TBI + LPS mice showed an impaired trajectory of weight gain post-LPS, reflecting a synergistic effect of TBI and the LPS-induced immune challenge. Flow cytometry analysis demonstrated innate immune cell activation in blood, brain, and spleen post-LPS; however, this was not potentiated by TBI. Cytokine protein levels in serum, and gene expression levels in the brain, were altered in response to LPS but not TBI across the time course. Immunofluorescence analysis of brain sections revealed increased glia reactivity due to injury, but no additive effect of LPS was observed.ConclusionsTogether, we found that a transient, infection-like systemic challenge had widespread effects on the brain and immune system, but these were not synergistic with prior TBI in pediatric mice. These findings provide novel insight into the potential influence of a secondary immune challenge to the injured pediatric brain, with future studies needed to elucidate the chronic effects of this two-hit insult.

Euglena tuba extract provides protection against lipopolysaccharide-induced inflammatory response and oxidative stress in mice.

Lipopolysaccharide (LPS), an endotoxin, is known to induce inflammatory response and oxidative stress in rodents. We evaluated the protective role of Euglena tuba extract (ETME) against LPS induced inflammatory response and oxidative stress in male Balb/c mice. Male Balb/c mice were divided into 4 groups. Group 1 (control) were intraperitoneally administered 0.5 mL PBS. Group 2, 3 and 4 were treated with a single dose of LPS (i.p. 40 mg/kg body weight). Prior 1 h, Group 3 and 4 received orally 100 mg/kg body weight and 200 mg/kg body weight ETME respectively. Biomarkers of oxidative stress including TBARS, SOD, Catalase, Liver marker enzyme (SGPT and SGOT), Nitric Oxide, and inflammatory cytokines including IL-6 and TNF-α, were estimated in serum. Oxidative stress and inflammatory markers were significantly increased in the LPS treated group, whereas ETME treated group at different concentrations protected mice from pro inflammatory cytokines and oxidative stress. Our results indicate that 70% methanolic extract of Euglena tuba can efficiently counteract free radical generation and increased level of inflammatory cytokine in an LPS induced mice model.

Hydroxytyrosol ameliorates oxidative challenge and inflammatory response associated with lipopolysaccharide-mediated sepsis in mice.

Hydroxytyrosol (HT) is among the main bioactive ingredients isolated from olive tree with a variety of biological and pharmacological activities. In the current study, the antioxidative and anti-inflammatory activities of HT were distinguished in the splenic tissue following lipopolysaccharide (LPS)-mediated septic response. Thirty-five Swiss mice were divided into five groups (n = 7): control, HT (40 mg/kg), LPS (10 mg/kg), HT 20 mg+LPS and HT 40 mg+LPS. HT was administered for 10 days, while a single LPS dose was applied. The obtained findings demonstrate that HT administration enhanced the survival rate and decreased lactate dehydrogenase level in LPS-challenged mice. Treatment with HT inhibited the incidence of oxidative damage in splenic tissue through decreasing lipoperoxidation and increasing antioxidant molecules, namely glutathione, superoxide dismutase and catalase. HT also decreased total leukocytes count, C-reactive protein, monocyte chemoattractant protein-1, and myeloperoxidase levels. Additionally, HT suppressed the production levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6. Moreover, mRNA expression of inducible nitric oxide synthase and nitric oxide production were increased after HT administration. Furthermore, HT supplementation resulted in a downregulation of p38 mitogen-activated protein kinase, inhibited the activation of the nuclear factor kappa-B from the nucleus to the cytoplasm, and attenuated infiltration of activated immune cells and tissue injury following LPS injection. Collectively, these findings demonstrate the antioxidative and anti-inflammatory properties of HT against LPS-mediated inflammation and sepsis. Therefore, HT could be applied as an alternative anti-inflammatory agent to minimize or prevent the development of systemic inflammatory response associated with septic shock.

Physical Exercise Exacerbates Acute Kidney Injury Induced by LPS via Toll-Like Receptor 4.

Introduction: Lipopolysaccharide (LPS) is a systemic response-triggering endotoxin, which has the kidney as one of its first targets, thus causing acute injuries to this organ. Physical exercise is capable of promoting physiological alterations and modulating inflammatory responses in the infectious process through multiple parameters, including the toll-like receptor (TLR)-4 pathway, which is the main LPS signaling in sepsis. Additionally, previous studies have shown that physical exercise can be both a protector factor and an aggravating factor for some kidney diseases. This study aims at analyzing whether physical exercise before the induction of LPS endotoxemia can protect kidneys from acute kidney injury.Methods: C57BL/6J male mice, 12 weeks old, were distributed into four groups: (1) sedentary (control, N = 7); (2) sedentary + LPS (N = 7); (3) trained (N = 7); and (4) trained + LPS (N = 7). In the training groups, the animals exercised 5×/week in a treadmill, 60 min/day, for 4 weeks (60% of max. velocity). Sepsis was induced in the training group by the application of a single dose of LPS (5 mg/kg i.p.). Sedentary animals received LPS on the same day, and the non-LPS groups received a saline solution instead. All animals were euthanized 24 h after the administration of LPS or saline.Results: The groups receiving LPS presented a significant increase in serum urea (p < 0.0001) and creatinine (p < 0.001) concentration and renal gene expression of inflammatory markers, such as tumor necrosis factor alpha and interleukin-6, as well as TLRs. In addition, LPS promoted a decrease in reduced glutathione. Compared to the sedentary + LPS group, trained + LPS showed overexpression of a gene related to kidney injury (NGAL, p < 0.01) and the protein levels of LPS receptor TLR-4 (p < 0.01). Trained + LPS animals showed an expansion of the tubulointerstitial space in the kidney (p < 0.05) and a decrease in the gene expression of hepatic AOAH (p < 0.01), an enzyme involved in LPS clearance.Conclusion: In contrast to our hypothesis, training was unable to mitigate the renal inflammatory response caused by LPS. On the contrary, it seems to enhance injury by accentuating endotoxin-induced TLR-4 signaling. This effect could be partly due to the modulation of a hepatic enzyme that detoxifies LPS.

Empagliflozin suppresses inflammation and protects against acute septic renal injury.

Sepsis-induced systemic inflammation response syndrome is the leading cause of morbidity and mortality among patients in intensive care units in North America. While sepsis is associated with multiple organ damage, acute renal injury represents a hallmark of sepsis. Since systemic and renal inflammation is known to play a vital role in morbidity and mortality associated with sepsis, identifying a potent anti-inflammatory agent may help minimize morbidity and mortality associated with acute septic kidney injury. Since recent work has suggested that empagliflozin, a renal sodium-glucose cotransporter 2 (SGLT2) inhibitor, may assist inthe treatment of inflammatory diseases, our objective was to examine the effect of empagliflozin on acute sepsis-induced renal injury. Mice were treated with three daily doses of empagliflozin or vehicle, with lipopolysaccharide (LPS) administered on the third day, at the same time as the third dose of empagliflozin or vehicle. In another cohort, mice were injected with a single dose of LPS 3 h before a dose of empagliflozin. Our results show that empagliflozin improves survival in a mouse model of LPS-induced septic shock. We further demonstrate that the beneficial effects of empagliflozin are likely mediated via reducing LPS-induced acute renal injury. Moreover, our data indicate that empagliflozin significantly reduces systemic and renal inflammation to contribute to the improvements observed inan LPS-model of acute septic renal injury. Overall, the findings of this study suggest that empagliflozin could be repurposed to reduce morbidity and mortality in patients with acute septic renal injury. Not applicable.

Gαq protein signaling in the bed nucleus of the stria terminalis regulate the lipopolysaccharide-induced despair-like behavior in mice.

Major depressive disorder (MDD) is highly comorbid with anxiety disorders. It has been reported that the bed nucleus of the stria terminalis (BNST) is important for the induction of anxiety and MDD. Recently, the Gαq protein signaling within the BNST is involved in the induction of anxiety through Gαq protein signaling-mediated RNA-editing of GluR2 subunit, which produces the calcium (Ca2+)-impermeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. On the other hand, the role of Gαq protein signaling within the BNST on the induction of MDD has never been reported yet. Therefore, we investigated whether Gαq protein signaling-producing the Ca2+-impermeable AMPA receptors in the BNST is involved in the lipopolysaccharide (LPS)-induced depressive-like behavior, particularly, despair-like behavior. When mice were systemically challenged with a single dose of LPS (1.2 mg/kg, i.p.), the immobility time during tail suspension test (TST) was increased 24 h after LPS injection. However, pretreatment with bilateral intra-BNST injection of neomycin (6.5 mM, 0.125 µL/side), an inhibitor of phospholipase C that is activated by Gαq protein-coupled receptor stimulation, extended the LPS-induced increase in the immobility time of TST. Furthermore, the co-pretreatment with bilateral intra-BNST injection of neomycin with 1-naphthylacetyl spermine (3 mM, 0.125 µL/side), an antagonist of Ca2+-permeable AMPA receptor, to mimic one of the final forms of Gαq protein activation, abolished the aggravated effect of neomycin and significantly shortened the immobility time compared with the control mice with an intra-BNST injection of artificial cerebrospinal fluid before LPS injection. However, pretreatment with bilateral intra-BNST injection of MDL-12,330A (10 µM, 0.125 µL/side), an inhibitor of adenylyl cyclase that is activated by Gαs protein-coupled receptor stimulation, did not affect the LPS-induced increase in the immobility time of TST. These results indicate that the Gαq protein signaling-mediated RNA-editing of GluR2, which produces the Ca2+-impermeable AMPA receptors within the BNST, regulates the LPS-induced despair-like behavior.