Meixia Huo

Regulation of Inflammatory Cytokines in Lipopolysaccharide-Stimulated RAW 264.7 Murine Macrophage by 7-O-Methyl-naringenin

7-O-Methylnaringenin, extracted from Rhododendron speciferum, belongs to the flavanone class of polyphenols. In the present study, we investigated the anti-inflammatory effects of 7-O-methylnaringenin on cytokine production by lipopoly-saccharide (LPS)-stimulated RAW 264.7 macrophages in vitro. The results showed that pretreatment with 10, 20 or 40 μg/mL of 7-O-methylnaringenin could downregulate tumour necrosis factor (TNF-α), interleukin (IL-6) and interleukin (IL-1β) in a dose-dependent manner. Furthermore, we investigated the signal transduction mechanisms to determine how 7-O-methylnaringenin affects RAW 264.7 macrophages. The activation of mitogen-activated protein kinases (MAPK) and IκBα were measured by Western blotting. The data showed that 7-O-methylnaringenin could downregulate LPS-induced levels of phosphorylation of ERK1/2, JNK and IκBα. These observations indicated that 7-O-methylnaringenin modulated inflammatory cytokine responses by blocking NF-қB, ERK1/2 and JNK/MAPKs activation.

Astragalin attenuates lipopolysaccharide-induced inflammatory responses by down-regulating NF-κB signaling pathway.

Astragalin (AG), a flavonoid from many traditional herbs and medicinal plants, has been described to exhibit in vitro anti-inflammatory activity. The present study aimed to determine the protective effects and the underlying mechanisms of astragalin on lipopolysaccharide-induced endotoxemia and lung injury in mice. Mice were injected intraperitoneally (i.p.) with lipopolysaccharide (LPS) (dose range: 5-40 mg/kg). We observed mice on mortality for 7 days twice a day and recorded survival rates. In drug testing, we examined the therapeutic effects of astragalin (25, 50 or 75 mg/kg) on LPS- induced endotoxemia by dosing orally astragalin 1 hour before LPS challenge. Using an experimental model of LPS-induced acute lung injury (ALI), we examined the effect of astragalin in resolving lung injury. The investigations revealed that pretreatment with astragalin can improve survival during lethal endotoxemia and attenuate inflammatory responses in a murine model of lipopolysaccharide-induced acute lung injury. The mechanisms by which Astragalin exerts its anti-inflammatory effect are correlated with inhibition of tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), and interleukin-6 (IL-6) production via inactivation of NF-κB.

In vitro and in vivo protection provided by pinocembrin against lipopolysaccharide-induced inflammatory responses

Pinocembrin or 5, 7-dihydroxyflavanone is a flavanone, a type of flavonoid. In the present study, we first assessed the anti-inflammatory effects of pinocembrin in RAW macrophage cells; and based on these effects, we investigated the therapeutic effects of pinocembrin in murine model of endotoxin-induced acute lung injury. We found that in vitro pretreatment with pinocembrin remarkably regulated the production of TNF-α, IL-1β, IL-6 and IL-10 via inhibiting the phosphorylation of IκBα, ERK1/2, JNK and p38MAPK. In the mouse model of LPS-induced acute lung injury, pinocembrin (20 or 50 mg/kg, i.p.) attenuated the development of pulmonary edema, histological severities, as well as neutrophil, lymphocyte and macrophage infiltration, which were increased by LPS administration. Additionally, TNF-α, IL-1β and IL-6 concentrations decreased significantly while the concentration of IL-10 was significantly increased after pinocembrin pretreatment. Our results also showed that pinocembrin attenuated LPS-induced lung injury through suppression of IκBα, JNK and p38MAPK activation. These findings suggest that pinocembrin may represent a novel candidate for the modulation of inflammatory responses.

Salidroside attenuates LPS-induced pro-inflammatory cytokine responses and improves survival in murine endotoxemia

Salidroside is a major component isolated from the Rhodiola rosea. In the present study, we investigated the anti-inflammatory effects of salidroside on cytokine production by lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in vitro, and the results showed that salidroside reduced tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) secretions. This inspired us to further study the effects of salidroside in vivo. Salidroside significantly attenuated TNF-α, IL-1β and IL-6 productions in serum from mice challenged with LPS, and consistent with the results in vitro. In the murine model of endotoxemia, mice were treated with salidroside prior to or after LPS challenge. The results showed that salidroside significantly increased mouse survival. Further studies revealed that salidroside could downregulate LPS-induced nuclear transcription factor-қB (NF-қB) DNA-binding activation and ERK/MAPKs signal transduction pathways production in RAW 264.7 macrophages. These observations indicated that salidroside modulated early cytokine responses by blocking NF-қB and ERK/MAPKs activation, and thus, increased mouse survival. These effects of salidroside may be of potential usefulness in the treatment of inflammation-mediated endotoxemia.

Traditional medicine alpinetin inhibits the inflammatory response in Raw 264.7 cells and mouse models

Alpinetin, one of the main constituents of the seeds of Alpinia katsumadai Hayata, belonging to flavonoids, has been known to exhibit antibacterial, anti-inflammatory and other important therapeutic activities. The purpose of this study was to investigate the protection of alpinetin on inflammation in Lipopolysaccharide (LPS) stimulated Raw 264.7 cells and LPS induced vivo lung injury model. The effects of alpinetin on pro-inflammatory cytokines and signaling pathways were analyzed by enzyme-linked immunosorbent assay and Western blot. The results showed that alpinetin markedly inhibited the LPS- induced TNF-α, IL-6 and IL-1β production both in vitro and vivo. Furthermore, alpinetin blocked the phosphorylation of IκBα protein, p65, p38 and extracellular signal-regulated kinase (ERK) in LPS stimulated RAW 264.7 cells. From in vivo study, it was also observed that alpinetin attenuated lung histopathologic changes in mouse models. These results suggest that alpinetin potentially decreases the inflammation in vitro and vivo, and might be a therapeutic agent against inflammatory diseases.

Paeonol suppresses lipopolysaccharide-induced inflammatory cytokines in macrophage cells and protects mice from lethal endotoxin shock

Paeonol (2′‐hydroxy‐4′‐methoxyacetophenone) is the main phenolic compound of the radix of Paeonia suffruticosa which has been used as traditional Chinese medicine. In this study, we primarily investigated the anti‐inflammatory effects and the underlying mechanisms of paeonol in RAW macrophage cells; and based on these effects, we assessed the protective effects of paeonol on lipopolysaccharide‐induced endotoxemia in mice. The in vitro study showed that paeonol regulated the production of TNF‐α, IL‐1β, IL‐6, and IL‐10 via inactivation of IκBα, ERK1/2, JNK, and p38 MAPK. In mouse model of lipopolysaccharide‐induced endotoxemia, pro‐ and anti‐inflammatory cytokines are significantly regulated, and thus the survival rates of lipolysaccharide‐challenged mice are improved by paeonol (150, 200, or 250 mg/kg). Therefore, paeonol has a beneficial activity against lipopolysaccharide‐induced inflammation in RAW 264.7 cell and mouse models.

Protective effects of salidroside from Rhodiola rosea on LPS-induced acute lung injury in mice.

Salidroside is a major component extracted from Rhodiola rosea. In this study, we investigated protective effects of salidroside on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. In the mouse model, we found that pretreatment with a single 120 mg/kg dose of salidroside prior to the administration of intratracheal LPS induced a significant decrease in the W/D ratio and mouse myeloperoxidase activity of lung, reduction protein concentration, the number of total cells, neutrophils and macrophages in the bronchoalveolar lavage fluid. In addition, salidroside also inhibited the production of several inflammatory cytokines, including tumor necrosis factor-α, interleukin-6 (IL-6) and IL-1β, and the NF-κB DNA-binding activation after LPS challenge. These results indicated that salidroside possess a protective effect on LPS-induced ALI in mice.

Suppression of LPS-induced inflammatory responses by gossypol in RAW 264.7 cells and mouse models

Gossypol, a yellowish polyphenolic compound originally from cotton plant, has been known to exert a potential for anti-cancer, anti-inflammatory and other important therapeutic activities. The purpose of this investigation was to determine the protection of gossypol on inflammation in Lipopolysaccharide (LPS) stimulated RAW 264.7 cells and LPS induced in vivo lung injury model. The effects of gossypol on pro-inflammatory cytokines and signaling pathways were evaluated by enzyme-linked immunosorbent assay and Western blot. The results showed that gossypol significantly inhibited the production of LPS-induced TNF-α, IL-6 and IL-1β both in vitro and vivo. Furthermore, gossypol blocked the phosphorylation of IκBα protein, p65, p38, c-Junterminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in LPS stimulated RAW 264.7 cells. From the in vivo study, it was observed that gossypol attenuated lung histopathologic changes in mouse models. The present data suggest that gossypol suppresses the inflammation in vitro and vivo, and may be a potential therapeutic candidate for the treatment of inflammatory disorders.

p-Cymene Modulates In Vitro and In Vivo Cytokine Production by Inhibiting MAPK and NF-κB Activation

The present study was designed to investigate the effects of p-cymene on lipopolysaccharide (LPS)-induced inflammatory cytokine production both in vitro and in vivo. The production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) in LPS-stimulated RAW 264.7 cells and C57BL/6 mice was evaluated by sandwich ELISA. Meanwhile, the mRNA levels of cytokine genes were examined in vitro by semiquantitative RT-PCR. In a further study, we analyzed the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways by western blotting. We found that p-cymene significantly regulated TNF-α, IL-1β, and IL-6 production in LPS-stimulated RAW 264.7 cells. Furthermore, the levels of relative mRNAs were also found to be downregulated. In in vivo trail, p-cymene markedly suppressed the production of TNF-α and IL-1β and increased IL-10 secretion. We also found that p-cymene inhibited LPS-induced activation of extracellular signal receptor-activated kinase 1/2, p38, c-Jun N-terminal kinase, and IκBα. These results suggest that p-cymene may have a potential anti-inflammatory action on cytokine production by blocking NF-κB and MAPK signaling pathways.

Protection of mice against lipopolysaccharide-induced endotoxic shock by pinocembrin is correlated with regulation of cytokine secretion

Abstract Natural products have been used as potentially important sources of anti-inflammatory drugs. This study examined the effects of pinocembrin against lipopolysaccharide (LPS)-induced endotoxemia to ascertain whether pinocembrin could protect mice from ensuing death. Cytokine responses were also assessed in serum isolated from blood collected at 0, 2, 4, 6, 8, and 24 h after LPS administration of the mice (with or without drug treatment). The results showed that there was a lower production of TNFα, IL-6, and IL-1β in the serum of LPS-challenged mice that had been pre-treated with pinocembrin. In addition, pre-treatment with pinocembrin improved host survival against the LPS-induced lethal endotoxemia. These results suggest that this new flavonoid could potentially be a novel candidate for preventing development/mitigation progression of septic shock.