Shikonin attenuates lipopolysaccharide-induced acute lung injury in mice

Shikonin potentiates skin wound healing in Sprague-Dawley rats by stimulating fibroblast and endothelial cell proliferation and angiogenesis

BACKGROUND

Shikonin, a major component of Lithospermum erythrorhizon, exerts anti-inflammatory and antibacterial effects and expedites wound healing. This study aims to evaluate the anti-inflammatory and antioxidant activities of shikonin in a Sprague-Dawley rat model and cell models using fibroblast and endothelial cells.

METHODS

The impact of shikonin on the activity of endothelial cells and fibroblasts was examined by cell counting kit 8 and wound-healing assays. A diabetic rat model was constructed, followed by wound creation for treatment with shikonin. Hematoxylin-eosin staining was used to assess pathological changes, and Masson's trichrome method to detect collagen deposition. Immunohistochemistry using antibodies against proliferating cell nuclear antigen and CD31 was conducted to detect proliferation and vascular density. Enzyme-linked immunosorbent assay and immunohistochemistry were carried out to assess pro-inflammatory and anti-inflammatory factor concentrations. Western blot and immunofluorescence were implemented to analyze oxidative stress-related protein expression.

RESULTS

Shikonin induced the activity of both fibroblasts and endothelial cells. Shikonin treatment contributed to facilitated wound healing and higher healing rates in rats. It also resulted in faster lesion debulking in tissues, reduced inflammatory infiltration, increased collagen deposition, and enhanced angiogenesis. Detection of markers at the wounds showed that shikonin accelerated cell proliferation, enhanced tissue remodeling, and inhibited oxidative stress.

CONCLUSION

Shikonin stimulates the proliferation and migration of fibroblasts and endothelial cells to promote angiogenesis and tissue remodeling, resulting in faster wound healing.

The extraction and anti-inflammatory screening of Onosma glomeratum Y. L. Liu

"Zicao" has a long medicinal history and has a variety of pharmacological activities. As the main resource of "zicao" in Tibet, Onosma glomeratum Y. L. Liu (tuan hua dian zi cao), usually used for treating pneumonia in Tibet, has not been reported deeply. In order to determine the main anti-inflammatory active ingredients of Onosma glomeratum Y. L. Liu, in this study, the extracts enriched in naphthoquinones and polysaccharides were optimized prepared form Onosma glomeratum Y. L. Liu by ultrasonic extraction, and reflux extraction, respectively, with Box-Behnken design effect surface method. And their anti-inflammatory abilities were screened on LPS induced A549 cells model, for figuring out the anti-inflammatory active ingredients from Onosma glomeratum Y. L. Liu.The extract enriched naphthoquinone was obtained under following condition: extract with 85% ethanol in a liquid to material ratio of 1:40 g/mL at 30 °C for 30 minutes using ultrasound, leading to the extraction rate of total naphthoquinone as 0.98 ± 0.017%; the extract enriched polysaccharides was prepared as follows: extract 82 minutes at 100 °C with distilled water in a liquid to material ratio of 1:50 g/mL, with extraction rate of polysaccharide as 7.07 ± 0.02%.On the LPS-induced A549 cell model, the polysaccharide extract from Onosma glomeratum Y. L. Liu showed better anti-inflammatory effects than the naphthoquinone extract, indicating the extract enriched in polysaccharides is the anti-inflammatory extract of Onosma glomeratum Y. L. Liu, which could serve as a potential anti-inflammatory extract in medical and food industries in the future.

Selected Phytochemicals to Combat Lungs Injury: Natural Care

The human has two lungs responsible for respiration and drug metabolism. Severe lung infection caused by bacteria, mycobacteria, viruses, fungi, and parasites may lead to lungs injury. Smoking and tobacco consumption may also produce lungs injury. Inflammatory and pain mediators are secreted by alveolar macrophages. The inflammatory mediators, such as cytokines, interleukin (IL)-1, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α, neutrophils, and fibroblasts are accumulated in the alveoli sac, which becomes infected. It may lead to hypoxia followed by severe pulmonary congestion and the death of the patient. There is an urgent need for the treatment of artificial respiration and ventilation. However, the situation may be the worst for patients suffering from lung cancer, pulmonary tuberculosis, and acute pneumonia caused by acute respiratory distress syndrome (ARDS). Re-urgency has been happening in the case of coronavirus disease of 2019 (COVID-19) patients. Therefore, it is needed to protect the lungs with the intake of natural phytomedicines. In the present review, several selected phyto components having the potential role in lung injury therapy have been discussed. Regular intake of natural vegetables and fruits bearing these constituents may save the lungs even in the dangerous attack of SARS-CoV-2 in lung cancer, pulmonary TB, and pneumatic patients.

Roots of Lithospermum erythrorhizon Alleviated Ovalbumin-Induced Allergic Rhinitis and IgE-triggered Degranulation of RBL-2H3 Cells

Lithospermum erythrorhizon (L. erythrorhizon) root is used in traditional medicine for its anti-inflammatory, antibacterial, and antioxidant properties. However, no studies have examined its impact on allergic rhinitis (AR). Here, we explored the protective effects of L. erythrorhizon in immunoglobulin E (IgE)-stimulated RBL-2H3 cells and in an ovalbumin (OVA)-induced AR mouse model. In the latter, we examined nasal mucosal inflammation, allergen-specific cytokine production, and histological changes to the nasal mucosa. In the mouse model, oral administration of an ethanol extract of L. erythrorhizon (LE) led to a marked reduction in rubbing and sneeze frequency, a significant decrease in serum OVA-specific IgE and IgG1 levels, and a significant increase in the IgG2a/IgG1 ratio. LE also reduced expression of interleukin (IL)-4, IL-5, and IL-13 in nasal lavage fluid (NALF), and suppressed inflammatory cell infiltration and epithelial degradation in nasal tissues. In IgE-stimulated RBL-2H3 cells, LE suppressed release of degranulation markers such as β-hexosaminidase and histamine. Based on these findings, we suggest that LE may ameliorate OVA-induced AR by regulating mast cell-mediated inflammatory responses.

Pharmacologic Activities of Plant-Derived Natural Products on Respiratory Diseases and Inflammations

Respiratory inflammation is caused by an air-mediated disease induced by polluted air, smoke, bacteria, and viruses. The COVID-19 pandemic is also a kind of respiratory disease, induced by a virus causing a serious effect on the lungs, bronchioles, and pharynges that results in oxygen deficiency. Extensive research has been conducted to find out the potent natural products that help to prevent, treat, and manage respiratory diseases. Traditionally, wider floras were reported to be used, such as Morus alba, Artemisia indica, Azadirachta indica, Calotropis gigantea, but only some of the potent compounds from some of the plants have been scientifically validated. Plant-derived natural products such as colchicine, zingerone, forsythiaside A, mangiferin, glycyrrhizin, curcumin, and many other compounds are found to have a promising effect on treating and managing respiratory inflammation. In this review, current clinically approved drugs along with the efficacy and side effects have been studied. The study also focuses on the traditional uses of medicinal plants on reducing respiratory complications and their bioactive phytoconstituents. The pharmacological evidence of lowering respiratory complications by plant-derived natural products has been critically studied with detailed mechanism and action. However, the scientific validation of such compounds requires clinical study and evidence on animal and human models to replace modern commercial medicine.

Methane Inhalation Protects Against Lung Ischemia-Reperfusion Injury in Rats by Regulating Pulmonary Surfactant via the Nrf2 Pathway

Methane (CH₄) exerted protective effects against lung ischemia-reperfusion (I/R) injury, but the mechanism remains unclear, especially the role of pulmonary surfactant. Therefore, this study aimed to explore the effects of CH₄ inhalation on pulmonary surfactant in rat lung I/R injury and to elucidate the mechanism. Rats were randomly divided into three groups (n = 6): the sham, I/R control, and I/R CH₄ groups. In the sham group, only thoracotomy was performed on the rats. In the I/R control and I/R CH₄ groups, the rats underwent left hilum occlusion for 90 min, followed by reperfusion for 180 min and ventilation with O₂ or 2.5% CH₄, respectively. Compared with those of the sham group, the levels of large surfactant aggregates (LAs) in pulmonary surfactant, lung compliance, oxygenation decreased, the small surfactant aggregates (SAs), inflammatory response, oxidative stress injury, and cell apoptosis increased in the control group (P < 0.05). Compared to the control treatment, CH₄ increased LA (0.42 ± 0.06 vs. 0.31 ± 0.09 mg/kg), oxygenation (201 ± 11 vs. 151 ± 14 mmHg), and lung compliance (16.8 ± 1.0 vs. 11.5 ± 1.3 ml/kg), as well as total antioxidant capacity and Nrf2 protein expression and decreased the inflammatory response and number of apoptotic cells (P < 0.05). In conclusion, CH₄ inhalation decreased oxidative stress injury, inflammatory response, and cell apoptosis, and improved lung function through Nrf2-mediated pulmonary surfactant regulation in rat lung I/R injury.

Natural product derived phytochemicals in managing acute lung injury by multiple mechanisms

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS) as common life-threatening lung diseases with high mortality rates are mostly associated with acute and severe inflammation in lungs. With increasing in-depth studies of ALI/ARDS, significant breakthroughs have been made, however, there are still no effective pharmacological therapies for treatment of ALI/ARDS. Especially, the novel coronavirus pneumonia (COVID-19) is ravaging the globe, and causes severe respiratory distress syndrome. Therefore, developing new drugs for therapy of ALI/ARDS is in great demand, which might also be helpful for treatment of COVID-19. Natural compounds have always inspired drug development, and numerous natural products have shown potential therapeutic effects on ALI/ARDS. Therefore, this review focuses on the potential therapeutic effects of natural compounds on ALI and the underlying mechanisms. Overall, the review discusses 159 compounds and summarizes more than 400 references to present the protective effects of natural compounds against ALI and the underlying mechanism.

Sinapultide-Loaded Microbubbles Combined with Ultrasound to Attenuate Lipopolysaccharide-Induced Acute Lung Injury in Mice

Purpose

Pulmonary surfactants (eg, sinapultide) are widely used for the treatment of lung injury diseases; however, they generally induce poor therapeutic efficacy in clinics. In this study, sinapultide-loaded microbubbles (MBs) were prepared and combined with ultrasound (US) treatment as a new strategy for improved treatment of lung injury diseases.

Methods

The combination treatment strategy of MBs combined with ultrasound was tested in a lipopolysaccharide (LPS)-induced mouse model of alveolar epithelial cells (AT II) and acute lung injury. Firstly, cytotoxicity, cytokines, and protein levels in LPS-mediated AT II cells were assessed. Secondly, the pathological morphology of lung tissue, the wet/dry (W/D) weight ratio, cytokines, and protein levels in LPS-mediated acute lung injury mice after treatment with the MBs were evaluated. Moreover, histology examination of the heart, liver, spleen, lung and kidney of mice treated with the MBs was performed to initially evaluate the safety of the sinapultide-loaded MBs.

Results

Sinapultide-loaded MBs in combination with ultrasound treatment significantly reduced the secretion of inflammatory cytokines and increased the expression of surfactant protein A (SP-A) in AT II cells. Furthermore, the pathological morphology of lung tissue, the wet/dry (W/D) weight ratio, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and SP-A expression level of mice treated with MBs and ultrasound were significantly improved compared to those of non-treated mice. In addition, the histology of the examined organs showed that the MBs had a good safety profile.

Conclusion

Sinapultide-loaded MBs combined with ultrasonic treatment may be a new therapeutic option for lung injury diseases in the clinic.

Phytochemicals: Potential Therapeutic Interventions Against Coronavirus-Associated Lung Injury

Since the outbreak of coronavirus disease 2019 (COVID-19) in December 2019, millions of people have been infected and died worldwide. However, no drug has been approved for the treatment of this disease and its complications, which urges the need for finding novel therapeutic agents to combat. Among the complications due to COVID-19, lung injury has attained special attention. Besides, phytochemicals have shown prominent anti-inflammatory effects and thus possess significant effects in reducing lung injury caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Also, the prevailing evidence reveales the antiviral effects of those phytochemicals, including anti-SARS-CoV activity, which could pave the road in providing suitable lead compounds in the treatment of COVID-19. In the present study, candidate phytochemicals and related mechanisms of action have been shown in the treatment/protection of lung injuries induced by various methods. In terms of pharmacological mechanism, phytochemicals have shown potential inhibitory effects on inflammatory and oxidative pathways/mediators, involved in the pathogenesis of lung injury during COVID-19 infection. Also, a brief overview of phytochemicals with anti-SARS-CoV-2 compounds has been presented.

Methane attenuates lung ischemia-reperfusion injury via regulating PI3K-AKT-NFκB signaling pathway

Objective: This study aims to investigate the protective effects and possible mechanism of methane-rich saline (MS) on lung ischemia-reperfusion injury (LIRI) in rats.Methods: MS (2 ml/kg and 20 ml/kg) was injected intraperitoneally in rats after LIRI. Lung injury was assayed by Hematoxylin-eosin (HE) staining and wet-to-dry weight (W/D). The cells in the bronchoalveolar lavage fluid (BALF) and blood were counted. Oxidative stress was examined by the level of malondialdehyde (MDA) and superoxide dismutase (SOD). Inflammatory factors including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-10 (IL-10) were determined by ELISA. Lung tissue apoptosis was detected by TUNEL staining and western blotting of Bcl-2, Bax, and caspase-3. The expressions of IкBα, p38, PI3K, AKT, and NF-κB were analyzed with Western blotting.Results: MS effectively decreased the lung W/D ratio as well as the lung pathological damage and reduced the localized infiltration of inflammatory cells. Methane suppressed the expression of the PI3K-AKT-NFκB signaling pathway during the lung IR injury, which inhibited the activation of NF-kB and decreased the level of inflammatory cytokines, such as TNF-α, IL-1β, and IL-10. Moreover, we found that MS treatment relieved reactive oxygen species (ROS) damage by downregulating MDA and upregulating SOD. MS treatment also regulated apoptosis-related proteins, such as Bcl-2, Bax, and caspase-3.Conclusions: MS could repair LIRI and reduce the release of oxidative stress, inflammatory cytokines, and cell apoptosis via the PI3K-AKT-NFκB signaling pathway, which may provide a novel and promising strategy for the treatment of LIRI.

Dioscin alleviates lipopolysaccharide-induced acute lung injury through suppression of TLR4 signaling pathways

Aim: Acute lung injury (ALI) is a life-threatening inflammatory syndrome that lacks an effective therapy. Dioscin, a natural steroid saponin isolated from a variety of herbs, could serve as an anti-inflammatory agent, as suggested in previous reports. The purpose of this study was to explore the effects of dioscin on lipopolysaccharide (LPS)-induced ALI and validate the potential mechanisms.Materials and Methods: An ALI model was induced by intratracheal administration of LPS. Dioscin (20, 40, and 80 mg/kg) was administered intragastrically once daily for seven consecutive days prior to LPS challenge.Results: Our data revealed that dioscin significantly suppressed LPS-induced lung pathological changes, pulmonary capillary permeability, pulmonary edema, inflammatory cell infiltration, myeloperoxidase (MPO) activity, and cytokine production, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and keratinocyte chemoattractant (KC). Moreover, dioscin inhibited LPS-induced nuclear factor-kappaB (NF-κB) activation as well as Toll-like receptor 4 (TLR4) expression.Conclusions: In brief, the results indicated that dioscin alleviates LPS-induced ALI through suppression of TLR4 signaling pathways.

Dipeptidyl Peptidase-4 (DPP-4) Inhibitor Saxagliptin Alleviates Lipopolysaccharide-Induced Acute Lung Injury via Regulating the Nrf-2/HO-1 and NF-B Pathways

PURPOSE

We aimed at investigating the effects of Dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin (Saxa) on mouse acute lung injury (ALI)-induced by lipopolysaccharide (LPS) and the potential mechanisms.

MATERIALS/METHODS

Animals were divided into four groups: control, Saxa, LPS, and LPS + Saxa. Histopathology changes of lung tissues were assessed by hematoxylin and eosin staining and periodic acid-Schiff staining. The degree of edema was determined by wet/dry ratio. The levels of oxidative stress markers and inflammatory cytokines in lung homogenate and bronchoalveolar lavage fluid were detected using kits. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay was used to test apoptosis and Western blotting was applied to measure the expression of apoptosis-associated proteins. The expression of nuclear factor erythroid 2-related factor 2 (Nrf-2)/heme oxygenase-1 (HO-1) and nuclear factor-kappa B (NF-κB) pathways were detected by Western blotting.

RESULTS

The results revealed that Saxa attenuated LPS-induced pathological injury and edema. Saxa decreased the levels of reactive oxygen species (ROS), malondialdehyde (MDA), myeloperoxidase (MPO) and increased the levels of superoxide dismutase (SOD) and catalase (CAT). The contents of inflammatory cytokines were reduced in the Saxa intervention group. Saxa attenuated apoptosis accompanied by alterations in the expression of apoptosis-associated proteins. Furthermore, the expression of Nrf-2 and HO-1 were upregulated whereas phospho (p)-NF-κB p65 and phospho-inhibitory subunit of NF-κB alpha (p-IκB-α) were downregulated after Saxa treatment.

CONCLUSION

These findings concluded that Saxa alleviates oxidative stress, inflammation and apoptosis in ALI induced by LPS via modulating the Nrf-2/HO-1 and NF-κB pathways, which provides evidence for employing Saxa in ALI treatment.

Alternative and Natural Therapies for Acute Lung Injury and Acute Respiratory Distress Syndrome

Introduction

Acute respiratory distress syndrome (ARDS) is a complex clinical syndrome characterized by acute inflammation, microvascular damage, and increased pulmonary vascular and epithelial permeability, frequently resulting in acute respiratory failure and death. Current best practice for ARDS involves “lung-protective ventilation,” which entails low tidal volumes and limiting the plateau pressures in mechanically ventilated patients. Although considerable progress has been made in understanding the pathogenesis of ARDS, little progress has been made in the development of specific therapies to combat injury and inflammation.

Areas Covered

In recent years, several natural products have been studied in experimental models and have been shown to inhibit multiple inflammatory pathways associated with acute lung injury and ARDS at a molecular level. Because of the pleiotropic effects of these agents, many of them also activate antioxidant pathways through nuclear factor erythroid-related factor 2, thereby targeting multiple pathways. Several of these agents are prescribed for treatment of inflammatory conditions in the Asian subcontinent and have shown to be relatively safe.

Expert Commentary

Here we review natural remedies shown to attenuate lung injury and inflammation in experimental models. Translational human studies in patients with ARDS may facilitate treatment of this devastating disease.

Shikonin inhibits myeloid differentiation protein 2 to prevent LPS-induced acute lung injury

BACKGROUND AND PURPOSE

Acute lung injury (ALI) is a challenging clinical syndrome, which manifests as an acute inflammatory response. Myeloid differentiation protein 2 (MD2) has an important role in mediating LPS-induced inflammation. Currently, there are no effective molecular-based therapies for ALI or viable biomarkers for predicting the severity of disease. Recent preclinical studies have shown that shikonin, a natural naphthoquinone, prevents LPS-induced inflammation. However, little is known about the underlying mechanisms.

EXPERIMENTAL APPROACH

The binding affinity of shikonin to MD2 was analysed using computer docking, surface plasmon resonance analysis and elisa. In vitro, the anti-inflammatory effect and mechanism of shikonin were investigated through elisa, real-time quantitative reverse transcription PCR, Western blotting and immunoprecipitation assay. In vivo, lung injury was induced by intratracheal administration of LPS and assessed by changes in the histopathological and inflammatory markers. The underlying mechanisms were investigated by immunoprecipitation in lung tissue.

KEY RESULTS

Shikonin directly bound to MD2 and interfered with the activation of toll-like receptor 4 (TLR4) induced by LPS. In cultured macrophages, shikonin inhibited TLR4 signalling and pro-inflammatory cytokine production. These effects were produced through suppression of key signalling proteins including the NF-κB and the MAPK pathway. We also showed that shikonin inhibits MD2-TLR4 complex formation and reduces LPS-induced inflammatory responses in a mouse model of ALI.

CONCLUSIONS AND IMPLICATIONS

Our studies have uncovered the mechanism underlying the biological activity of shikonin in ALI and suggest that the targeting of MD2 may prove to be beneficial as a treatment option for this condition.

Shikonin protects against D-Galactosamine and lipopolysaccharide-induced acute hepatic injury by inhibiting TLR4 signaling pathway

Shikonin, a naphthoquinone isolated from the root of medical herb Lithospermum erythrorhizon, has been reported to have anti-inflammatory effect. However, there is no related research for the treatment of shikonin on hepaic injury. The purpose of this study was to investigate the effects of shikonin on D-Galactosamine and Lipopolysaccharide-induced hepatic injury in mice. Male BALB/c mice were pretreated with shikonin 1 h before LPS/D-GalN treatment. The pathological changes of hepatic injury were detected by H&E staining. The levels of TNF-α and IL-1β in hepatic tissues were detected by ELISA. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also measured in this study. In addition, the expression of TLR4 and NF-κB were determined by western blot analysis. These results suggest that shikonin effectively prevents LPS/D-GalN-induced liver injury by inhibiting AST and ALT levels, as well as inflammatory cytokines TNF-α and IL-1β production. The expression of TLR4 and NF-κB activation induced by LPS/D-GalN were also inhibited by treatment of shikonin. In vitro, shikonin significantly inhibited LPS-induced TNF-α and IL-1β production, as well as TLR4 expression and NF-κB activation. In conclusion, the results of the present study suggest that shikonin attenuates LPS/D-GalN-induced hepatic injury by inhibiting TLR4 signaling pathway.

Shikonin alleviates allergic airway remodeling by inhibiting the ERK-NF-κB signaling pathway

Shikonin is a naphthoquinone extracted from the root of Lithospermum erythrorhizon, and has been reported to suppress allergic airway inflammation in mice. However, the underlying mechanisms are unclear and need to be further elucidated. In this study, shikonin (0.5, 2 or 4mg/kg) was given intraperitoneally to ovalbumin (OVA)-challenged BALB/c mice. We found that the pathological airway remodeling of asthmatic mice was alleviated by shikonin, and the infiltrated inflammatory cells and collagen deposition in their lungs were reduced. Furthermore, the abnormal activation of extracellular signal-regulated kinase (ERK)/nuclear factor-κB (NF-κB) pathway and the elevation of matrix metalloproteinase 9 (MMP9) in the lung of asthmatic mice were suppressed by shikonin. The inactivation of NF-κB by shikonin was at least in part via inhibiting IκBα activation. In vitro, the treatment of shikonin inhibited the platelet-derived growth factor (PDGF)-induced proliferation of primary airway smooth muscle cells (ASMCs), and induced a G0/G1 arrest in these cells. In addition, ASMCs exposed to PDGF acquired an enhanced migratory ability, and the activities of MMP9 and matrix metalloproteinase 2 (MMP2) and expression of MMP9 of these cells were significantly up-regulated. These PDGF-induced alterations were also inhibited by shikonin. The inhibitory effects of shikonin on the proliferation and migration of ASMCs were comparable to pyrrolidinedithiocarbamate (PDTC), an inhibitor of NF-κB pathway. In conclusion, the present study sheds lights on how shikonin alleviates allergic airway remodeling.

Shikonin Inhibits Inflammatory Cytokine Production in Human Periodontal Ligament Cells

Shikonin, which is derived from Lithospermum erythrorhizon, a herb used in traditional medicine, has long been considered to be a useful treatment for various diseases in traditional oriental medicine. Shikonin has recently been reported to have several pharmacological properties, e.g., it has anti-microbial, anti-tumor, and anti-inflammatory effects. The aim of this study was to examine whether shikonin is able to influence the production of interleukin (IL)-6, IL-8, and/or chemokine C-C motif ligand (CCL)20, which contribute to the pathogenesis of periodontal disease, in human periodontal ligament cells (HPDLC). The production levels of IL-6, IL-8, and CCL20 in HPDLC were determined using an ELISA. Western blot analysis was used to detect nuclear factor kappa B (NF-κB) pathway activation in HPDLC. Shikonin prevented IL-1β- or tumor necrosis factor (TNF)-α-mediated IL-6, IL-8, and CCL20 production in HPDLC. Moreover, we found that shikonin suppressed the phosphorylation and degradation of inhibitor of kappa B-alpha (IκB-α) in IL-1β- or TNF-α-stimulated HPDLC. These findings suggest that shikonin could have direct beneficial effects against periodontal disease by reducing IL-6, IL-8, and CCL20 production in periodontal lesions.

Therapeutic Potential of Medicinal Plants and Their Constituents on Lung Inflammatory Disorders

Acute bronchitis and chronic obstructive pulmonary diseases (COPD) are essentially lung inflammatory disorders. Various plant extracts and their constituents showed therapeutic effects on several animal models of lung inflammation. These include coumarins, flavonoids, phenolics, iridoids, monoterpenes, diterpenes and triterpenoids. Some of them exerted inhibitory action mainly by inhibiting the mitogen-activated protein kinase pathway and nuclear transcription factor-κB activation. Especially, many flavonoid derivatives distinctly showed effectiveness on lung inflammation. In this review, the experimental data for plant extracts and their constituents showing therapeutic effectiveness on animal models of lung inflammation are summarized.

Ratiometric Two-Photon Fluorescent Probe for in Vivo Hydrogen Polysulfides Detection and Imaging during Lipopolysaccharide-Induced Acute Organs Injury

Acute organ injury observed during sepsis, caused by an uncontrolled release of inflammatory mediators, such as lipopolysaccharide (LPS), is quite fatal. The development of efficient methods for early diagnosis of sepsis and LPS-induced acute organ injury in living systems is of great biomedical importance. In living systems, cystathionine γ-lyase (CSE) can be overexpressed due to LPS, and H₂S_n can be formed by CSE-mediated cysteine metabolism. Thus, acute organ injury during sepsis may be correlated with H₂S_n levels, making accurate detection of H₂S_n in living systems of great physiological and pathological significance. In this work, our previously reported fluorescent platform was employed to design and synthesize a FRET-based ratiometric two-photon (TP) fluorescent probe TPR-S, producing a large emission shift in the presence of H₂S_n. In this work, a naphthalene derivative two-photon fluorophore was chosen as the energy donor; a rhodol derivative fluorophore served as the acceptor. The 2-fluoro-5-nitrobenzoate group of probe TPR-S reacted with H₂S_n and was selectively removed to release the fluorophore, resulting in a fluorescent signal decrease at 448 nm and enhancement at 541 nm. The ratio value of the fluorescence intensity between 541 and 448 nm (I_541 nm/I_448 nm) varied from 0.13 to 8.12 (∼62-fold), with the H₂S_n concentration changing from 0 to 1 mM. The detection limit of the probe was 0.7 μM. Moreover, the probe was applied for imaging H₂S_n in living cells, tissues, and organs of LPS-induced acute organ injury, which demonstrated its practical application in complex biosystems as a potential method to achieve early diagnosis of LPS-induced acute organ injury.

Effect of shikonin on concanavalin A-induced liver injury and possible mechanisms involved

AIM

To investigate the effect of shikonin on concanavalin A (Con A)-induced acute liver injury in mice and explore the underlying mechanisms.

METHODS

Acute liver injury was induced by Con A in Balb/c mice through tail injection. The mice were randomly divided into five groups of fourteen mice as follows: (1) normal group; (2) Con A-induced model group; (3) low-dose (12.5 mg/kg) shikonin + Con A group; (4) medium-dose (25 mg/kg) shikonin + Con A group; (5) high-dose (50 mg/kg) shikonin + Con A group. Histological grading and the measurement of the levels of alanine transaminase (ALT), aspartate transaminase (AST), nitric oxide (NO), inducible nitric oxide synthase (iNOS), nuclear factor-κB (NF-κB), IκBα and IκBβ were performed.

RESULTS

Compared to the normal group, the histological grade as well as the levels of ALT, AST, NO, iNOS and NF-κB significantly increased in the model group, but the levels of IκBα and IκBβ were decreased. After shikonin (50 mg/kg) treatment, the histological grade and the levels of ALT, AST, NO, iNOS and NF-κB significantly were decreased, and the levels of IκBα and IκBβ were increased. The doses of 12.5 mg/kg and 25 mg/kg worked inefficiently.

CONCLUSION

Shikonin (50 mg/kg) protects against Con A-induced liver injury by decreasing the level of NO, which may correlate with the amelioration of NF-κB activity.

Shikonin induces apoptosis of lung cancer cells via activation of FOXO3a/EGR1/SIRT1 signaling antagonized by p300

Shikonin derivatives exert powerful cytotoxic effects including induction of apoptosis. Here, we demonstrate the cytotoxic efficacy of shikonin in vivo in xenograft models, which did not affect body weight as well as its reduction of cell viability in vitro using several non-small cell lung cancer (NSCLC) cell lines. We found that inhibition of AKT by shikonin activated the forkhead box (FOX)O3a/early growth response protein (EGR)1 signaling cascade and enhanced the expression of the target gene Bim, leading to apoptosis in lung cancer cells. Overexpression of wild-type or a constitutively active mutant of FOXO3a enhanced shikonin-induced Bim expression. The NAD⁺-dependent histone deacetylase sirtuin (SIRT)1 amplified the pro-apoptotic effect by deacetylating FOXO3a, which induced EGR1 binding to the Bim promoter and activated Bim expression. Meanwhile, PI3K/AKT activity was enhanced, whereas that of FOXO3a was reduced and p300 was upregulated by treatment with a sublethal dose of shikonin. FOXO3a acetylation was enhanced by p300 overexpression, while shikonin-induced Bim expression was suppressed by p300 overexpression, which promoted cell survival. FOXO3a acetylation was increased by p300 overexpression and treatment with SIRT1 inhibitor, improving cell survival. In addition, shikonin-induced FOXO3a nuclear localization was blocked by AKT activation and SIRT1 inhibition, which blocked Bim expression and conferred resistance to the cytotoxic effects of shikonin. The EGR1 increase induced by shikonin was restored by pretreatment with SIRT1 inhibitor. These results suggest that shikonin induces apoptosis in some lung cancer cells via activation of FOXO3a/EGR1/SIRT1 signaling, and that AKT and p300 negatively regulate this process via Bim upregulation.

Arctigenin Protects against Lipopolysaccharide-Induced Pulmonary Oxidative Stress and Inflammation in a Mouse Model via Suppression of MAPK, HO-1, and iNOS Signaling

Arctigenin, a bioactive component of Arctium lappa (Nubang), has anti-inflammatory activity. Here, we investigated the effects of arctigenin on lipopolysaccharide (LPS)-induced acute lung injury. Mice were divided into four groups: control, LPS, LPS + DMSO, and LPS + Arctigenin. Mice in the LPS + Arctigenin group were injected intraperitoneally with 50 mg/kg of arctigenin 1 h before an intratracheal administration of LPS (5 mg/kg). Lung tissues and bronchoalveolar lavage fluids (BALFs) were collected. Histological changes of the lung were analyzed by hematoxylin and eosin staining. Arctigenin decreased LPS-induced acute lung inflammation, infiltration of inflammatory cells into BALF, and production of pro-inflammatory cytokines. Moreover, arctigenin pretreatment reduced the malondialdehyde level and increased superoxide dismutase and catalase activities and glutathione peroxidase/glutathione disulfide ratio in the lung. Mechanically, arctigenin significantly reduced the production of nitric oxygen and inducible nitric oxygen synthase (iNOS) expression, enhanced the expression of heme oxygenase-1, and decreased the phosphorylation of mitogen-activated protein kinases (MAPKs). Arctigenin has anti-inflammatory and antioxidative effects on LPS-induced acute lung injury, which are associated with modulation of MAPK, HO-1, and iNOS signaling.

Protective effects of patchouli alcohol isolated from Pogostemon cablin on lipopolysaccharide-induced acute lung injury in mice

Patchouli alcohol (PA) is a tricyclic sesquiterpene isolated from Pogostemon cablin, which exerts anti-inflammatory, anti-influenza and cognitive-enhancing bioactivities. The present study aimed to investigate the protective effects of PA on acute lung injury (ALI) induced by intratracheal instillation of lipopolysaccharide (LPS) in mice. Dexamethasone was used as a positive drug for protection against LPS-induced ALI. The results of the present study demonstrated that pretreatment with PA significantly increased survival rate, attenuated histopathologic damage and lung edema, and decreased the protein content in the bronchoalveolar lavage fluid (BALF) of mice with ALI. Furthermore, PA significantly inhibited the expression levels of proinflammatory cytokines, including tumor necrosis factor (TNF)-α and interleukin (IL)-6 in the BALF, downregulated the levels of myeloperoxidase and malondialdehyde, and upregulated the activity levels of superoxide dismutase and glutathione peroxidase in lung tissue. These results indicated that PA may exert potent protective effects against LPS-induced ALI in mice, the mechanisms of which are possibly associated with the anti-inflammatory and antioxidative activities of PA.

Shikonin inhibits TNF-α-induced growth and invasion of rat aortic vascular smooth muscle cells

Shikonin is a naphthoquinone compound extracted from the Chinese herb purple gromwell. Shikonin has broad antibacterial, anti-inflammatory, and antitumor activities. The tumor necrosis factor-α (TNF-α)-induced proliferation and invasion of vascular smooth muscle cells (VSMCs) is an important factor that contributes to atherosclerosis. The effects of shikonin on the proliferation and apoptosis of VSMCs have been reported; however, the function of shikonin on TNF-α-mediated growth and invasion of VSMCs during atherosclerosis remains unclear. In this study, we used Western blot, flow cytometry, real-time quantitative PCR, and enzyme-linked immunosorbent assay to investigate the effect of shikonin on the TNF-α-induced growth and invasion of VSMCs and to determine the underlying mechanism. Our results showed that shikonin inhibits the TNF-α-mediated growth and invasion. Further study revealed that shikonin regulates the activation of nuclear factor kappa B and phosphatidyl inositol 3-kinase signaling pathways; modulates the expression of cyclin D1, cyclin E, B-cell lymphoma 2, and Bax; activates caspase-3 and caspase-9; induces cell cycle arrest; and promotes the apoptosis of VSMCs. Together, our results indicate that shikonin may become a promising agent for the treatment of atherosclerosis and they also establish foundation for the development of anti-atherosclerosis drugs.

Melatonin attenuates intestinal ischemia--reperfusion-induced lung injury in rats by upregulating N-myc downstream-regulated gene 2

BACKGROUND

Successful drug treatment for ischemia--reperfusion-induced lung injury remains a major clinical problem. Melatonin (MT) is a hormone that is principally synthesized in the pineal gland. It has been shown to exhibit a variety of functions including anti-inflammatory and antioxidant effects. Previous reports on N-myc downstream-regulated gene (NDRG)2 have suggested that it is involved in cellular differentiation, development, antiapoptosis, anti-inflammatory cytokine, and antioxidant. The objective of this study was to test whether MT, a novel NDRG2 activator, can protect against intestinal ischemia-reperfusion-induced lung injury (IIRI).

MATERIALS AND METHODS

IIRI was induced in rats by occlusion of the superior mesenteric artery for 60 min, and the occlusion was then released for reperfusion. Rats were randomly divided into six groups as follows: control group; MT group; IIRI group; IIRI+5 mg/kg MT group; IIRI+15 mg/kg MT group; and IIRI+25 mg/kg MT group. The effects of MT on intestinal ischemia-reperfusion-induced lung pathologic changes, inflammatory cytokines release, myeloperoxidase and superoxide dismutase activities, and malondialdehyde level were examined. In addition, the NDRG2 activation in lung tissues was detected by Western blot analysis.

RESULTS

MT pretreatment attenuated edema and the pathologic changes in the lung. MT also decreased the levels of tumor necrosis factor-α, interleukin-1β, and interleukin-8 in bronchoalveolar lavage fluid. In addition, MT markedly prevented IIRI-induced elevation of malondialdehyde and myeloperoxidase levels, as well as reduction of superoxide dismutase activity. Furthermore, the expression of NDRG2 was activated by MT pretreatment in lung tissues.

CONCLUSIONS

The present study demonstrates that MT exerted protection against IIRI-induced oxidative stress. The potential mechanism of this action may attribute partly to the activation of NDRG2 expression.

Valproic acid attenuates lipopolysaccharide-induced acute lung injury in mice

Valproic acid (VPA) has been shown to exert anti-inflammatory and antioxidant effects in a range of diseases including septic shock. However, the effects of VPA on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remains not well understood. We found that VPA pretreatment attenuated the LPS-induced ALI, as evidenced by the reduced histological scores, myeloperoxidase activity, and wet-to-dry weight ratio in the lung tissues. This was accompanied by the downregulated nuclear factor kappa B (NF-κB) p65, nitric oxide, and inducible nitric oxide synthase in the lung tissues and the decreased levels of tumor necrosis factor alpha and interleukin-1β in the bronchoalveolar lavage fluid. Furthermore, VPA reduced the nuclear histone deacetylase (HDAC)3 expression whereas increased the cytoplasmic HDAC3 expression. Our results suggested that VPA attenuates the LPS-induced ALI via inhibiting the NF-κB activation probably through a mechanism depending on HDAC3 redistribution.

Shikonin inhibits the lipopolysaccharide-induced release of HMGB1 in RAW264.7 cells via IFN and NF-κB signaling pathways

To study the anti-inflammation effect of Shikonin (Shik) and its mechanism, murine macrophage-like RAW264.7 cells (RAW264.7 cells) were divided into control group, LPS group (0.125, 0.25 and 0.5μg/ml), LPS (0.125, 0.25 and 0.5μg/ml) plus Shik (0.5, 1 and 2μM) group, and Shik (2μM) group. After exposure for 24h, the levels of Interleukin-6 (IL-6), nitric oxide (NO) and Tumor Necrosis Factor-α (TNF-α) in supernatant were measured with ELISA, the expression of high mobility group box 1(HMGB1) in supernatant and cytoplasm was assayed using qRT-PCR, western blot and immunofluorescence assays, the expression of IFN-β in cellular and supernatant was assayed by qRT-PCR and ELISA, and the ratio of nuclear to cytoplasm for NF-κB protein expression was assayed using western blot. The results of our investigation demonstrated that Shik could reduce significantly the levels of IL-6, NO and TNF-α in RAW264.7 cells exposed to LPS (P<0.05 or P<0.01). The expression of HMGB1, IFN-β and the ratio of nuclear to cytoplasm for NF-κB protein expression in LPS plus Shik group declined significantly as compared with LPS group (P<0.05 or P<0.01). The inhibitors of IFN-β signaling molecule JAK and NF-κB could attenuate significantly the expression of HMGB1 in supernatant. It was found in the present study that Shik could have the anti-inflammatory effects in RAW264.7 cells exposed to LPS, and one of the mechanisms may be the down-regulation of HMGB expression, which was associated with the IFN-β and NF-κB signaling pathways.