Protective effects of HY1702 on lipopolysaccharide-induced mild acute respiratory distress syndrome in mice

Antipyretic and Anti-Inflammatory Effects of Rectal Administration of Reduning Injection in Feverish Rats Induced by Lipopolysaccharide

This study aimed to explore the antipyretic and anti-inflammatory effects of rectal administration of Reduning injection in feverish rats induced by lipopolysaccharide (LPS), and observe the temperature changes and inflammatory indexes. The selected rats were randomly divided into 6 groups, with 10 rats in each group, named as normal empty group, model group, intravenous group (2 mL/kg), low-dose enema group (1 mL/kg), middle-dose enema group (2 mL/kg), and high-dose enema group (4 mL/kg). The hourly temperature variations in rats injected with LPS in the abdomen were recorded. Five hours later, blood samples from the abdominal aorta were collected to monitor immunoglobulin M (IgM), immunoglobulin A (IgA), interleukin (IL)-6, and tumor necrosis factor (TNF)-α. At 5 hours, the fever peak induced by LPS appeared, and obvious antipyretic effects were observed; the effect was optimal in the medium dose enema group at 4 hours (p < 0.05); the IgM value in the enema groups, the intravenous group, and normal empty group was significantly lower than that in the model group; the IgA value in each group was higher than that in the model group, but there was no statistical significance (p > 0.05); values of IL-6 and TNF-α in each group were lower than those in the model group, and the difference was statistically significant except for the high-dose enema group (p > 0.05). Low-dose and medium-dose rectal administration of Reduning injection have inhibitory effects on IL-6, TNF-α, and IgM in feverish rats induced by LPS, but there is no obvious difference compared to intravenous administration and it could achieve an anti-inflammatory effect. There is a possibility of enhancing IgA immunity with rectal administration, but there is no obvious difference compared to intravenous administration, and rectal administration has no significant effect on mucosal immunity.

Glaucocalyxin A alleviates lipopolysaccharide‑induced inflammation and apoptosis in pulmonary microvascular endothelial cells and permeability injury by inhibiting STAT3 signaling

Glaucocalyxin A (GLA), an ent-kauranoid diterpene derived from Rabdosia japonica var. glaucocalyx, possesses antibacterial, anti-oxidative and anti-neuroinflammatory properties. The present study aimed to investigate the potential mechanisms underlying GLA in the pathogenesis of pneumonia. Human pulmonary microvascular endothelial cells (hPMVECs) treated with lipopolysaccharide (LPS) were treated with GLA, followed by the detection of cell viability, inflammation, apoptosis and cell permeability. Furthermore, the protein expression levels of apoptosis- and permeability-associated proteins were determined using western blot analysis. Following treatment with a signal transducer and activator of transcription 3 (STAT3) activator, the protein expression levels of STAT3 and endoplasmic reticulum stress-associated proteins were determined, to confirm whether STAT3 signaling was mediated by GLA. Lastly, the mRNA expression level of inflammatory cytokines, apoptosis and permeability injury were also determined following treatment with a STAT3 activator. The results revealed that GLA ameliorated inflammation, apoptosis and permeability injury in LPS-induced hPMVECs. Following treatment with a STAT3 activator, the therapeutic effects of GLA on LPS-induced hPMVECs were abrogated. In conclusion, GLA alleviated LPS-induced inflammation, apoptosis and permeability injury in hPMVECs by inhibiting STAT3 signaling, which highlighted the potential therapeutic value of GLA in the treatment of pneumonia.

Lipocalin-2 silencing suppresses inflammation and oxidative stress of acute respiratory distress syndrome by ferroptosis via inhibition of MAPK/ERK pathway in neonatal mice

Neonatal acute respiratory distress syndrome (ARDS) has high morbidity and mortality rates worldwide, but there is a lack of pharmacologic treatment and clinical targeted therapies. In this study, we aimed to explore the effects of Lipocalin-2 (LCN2) on ferroptosis-mediated inflammation and oxidative stress in neonatal ARDS and the potential mechanism. In this study, we established an in vivo ARDS mouse model and an in vitro ARDS cell model by LPS (Lipopolysaccharide) stimulation. Lung tissue injury was evaluated by wet/dry ratios and histopathological examination. LCN2 expression was detected by qRT-PCR and Western blot. Inflammatory factors, oxidative stress and apoptosis were also detected. Ferroptosis was identified by detection of Fe²⁺ level and ferroptosis-associated protein expressions. Mitogen-activated protein kinases (MAPK)/extracellular signal-regulated kinase (ERK) pathway signaling was examined by Western blot analysis. The data revealed that LCN2 expression was significantly upregulated in neonatal mice with ARDS. Interference with LCN2 protected LPS-induced lung in neonatal mouse by reducing the radio of wet/dry and alleviating pathological damages. In addition, LCN2 silencing repressed LPS-induced inflammation, oxidative stress in vivo and in vitro, as well as apoptosis. Meanwhile, decreased level of Fe²⁺ and transferrin while increased levels of ferritin heavy chain 1 (FTH1) and glutathione peroxidase 4 (GPX4) were observed. The expression MAPK/ERK pathway was inhibited by depletion of LCN2. The present results suggest that LCN2 knockdown protected LPS-induced ARDS model via inhibition of ferroptosis-related inflammation and oxidative stress by inhibiting the MAPK/ERK pathway, thereby presenting a novel target for the treatment of ARDS.

Glaucocalyxin A Ameliorates Hypoxia/Reoxygenation-Induced Injury in Human Renal Proximal Tubular Epithelial Cell Line HK-2 Cells

Ischemia-reperfusion injury is one of the major causes of acute kidney injury (AKI), which is increasingly prevalent in clinical settings. Glaucocalxin A (GLA), a biologically ent-kauranoid diterpenoid, has various pharmacological effects like antioxidation, immune regulation, and antiatherosclerosis. In this study, the effect of GLA on AKI and its mechanism were studied in vitro. HK-2 human renal tubular epithelial cells were exposed to hypoxia/reoxygenation (H/R), which were established as an in vitro AKI model. Subsequently, the mRNA expressions of inflammatory and antioxidant factors were determined by quantitative reverse transcription polymerase chain reaction (RT-qPCR). Reactive oxygen species (ROS) production and cell death were detected by fluorescence-activated cell sorting. GLA pre-treatment improved the cell viability of HK-2 cells exposed to H/R. GLA suppressed the H/R-induced ROS production in HK-2 cells. GLA also elevated the activities of superoxide dismutase of HK-2 cells exposed to H/R. Moreover, GLA prevented H/R-induced cell death in HK-2 cells. Furthermore, GLA ameliorated the activation of the protein kinase B (Akt)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in HK-2 cells exposed to H/R. Our findings suggested that GLA protected HK-2 cells from H/R-induced oxidative damage, which was mediated by the Akt/Nrf2/HO-1 signaling pathway. These results indicate that GLA may serve as a promising therapeutic drug for AKI.

[2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-d-glucoside alleviates lipopolysaccharide-induced acute lung injury in rats]

OBJECTIVE

To observe the protective effect of 2, 3, 5, 4'-tetrahydroxystilbene-2-O-β-d-glucoside (TSG) against lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats and explore the underlying mechanism.

METHODS

Thirty-six SD rats were randomized equally into 4 groups: the normal control group, ALI model group, and low- and high-dose TSG groups (treated with 50 and 100 mg/kg TSG via intragastric administration, respectively). In all but the normal control group, the rats were subjected to tail vein injection of LPS to induced ALI. The rats were euthanized at 6 h after the injection for pathological examination of the lungs. The wet/dry weight ratio (W/D) of the lungs were calculated, and superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the lung tissues and serum levels of TNF-α and IL-6 were determined. Western blotting was performed to detect the levels of NF-κB p65 in the lungs.

RESULTS

Compared with those in LPS group, the TSGtreated rats showed significantly milder lung pathologies (P < 0.001) and had lower serum TNF-α and IL-6 levels (P < 0.001) and W/D of the lung tissues (P < 0.001), higher SOD activity (P < 0.001) and lower MDA content in the lungs (P < 0.001), and significantly lower expression of NF-κB p65 in the lungs (P < 0.001). None of these indices showed significant differences between the lowand high-dose TSG treatment groups (P>0.05).

CONCLUSIONS

TSG can ameliorate LPS-induced ALI in rats possibly by suppressing the NF-κB pathway to improve the antioxidant capacity and decrease the release of inflammatory factors.

The Association Between the Baseline and the Change in Neutrophil-to-Lymphocyte Ratio and Short-Term Mortality in Patients With Acute Respiratory Distress Syndrome

Background: Two previous studies have shown that increased neutrophil to lymphocyte ratio (NLR) is associated with short-term prognosis in patients with acute respiratory distress syndrome (ARDS), but it is usually assessed as a single threshold value at baseline. We investigated the relationship between the baseline and the early change in NLR and 30-day mortality in patients with ARDS to evaluate the prognostic value of NLR baseline and NLR changes during the first 7 days after ICU admission. Methods: This is a retrospective cohort study, with all ARDS patients diagnosed according to the Berlin definition from the Medical Information Mart for Intensive Care III (MIMIC-III) database. We calculated the NLR by dividing the neutrophil count by the lymphocyte count. The multivariable logistic regression analysis was used to investigate the relationship between the baseline NLR and short-term mortality. Then the generalized additive mixed model was used to compare trends in NLR over time among survivors and non-survivors after adjusting for potential confounders. Results: A total of 1164 patients were enrolled in our study. Multivariable logistic regression analysis showed that after adjusting for confounders, elevated baseline NLR was a significant risk factor predicting 30-day mortality (OR 1.02, 95%CI 1.01, 1.03, P = 0.0046) and hospital mortality (OR 1.02, 95%CI 1.01, 1.03, P = 0.0003). The result of the generalized additive mixed model showed that the NLR decreased in the survival group and increased in the non-survival group gradually within 7 days after ICU admission. The difference between the two groups showed a trend of increase gradually and the difference increased by an average of 0.67 daily after adjusting for confounders. Conclusions: We confirmed that there was a positive correlation between baseline NLR and short-term mortality, and we found significant differences in NLR changes over time between the non-survival group and the survival group. The early increase in NLR was associated with short-term mortality in ARDS patients.