Pinitol attenuates LPS-induced pneumonia in experimental animals: Possible role via inhibition of the TLR-4 and NF-κB/IκBα signaling cascade pathway.

Pneumonia is a chronic disorder of the respiratory system associated with worsening quality of life and a significant economic burden. Pinitol, a plant cyclic polyol, has been documented for immune-inflammatory potential. The aim of present investigation was to evaluate the potential and possible mechanism of action of pinitol against lipopolysaccharide (LPS)-induced pneumonia in the experimental animal model. Pneumonia was induced in Sprague-Dawley rats by intratracheal administration of LPS (2 mg/kg). Animals were treated with either vehicle or dexamethasone or pinitol (5 or 10 or 20 mg/kg). Potential of pinitol against LPS-induced pulmonary insult was assessed based on behavioral, biochemical, molecular, and ultrastructural studies. Intratracheal instillation of LPS induced significant (P < .05) inflammatory infiltration in bronchoalveolar lavage fluid (BALF) and lung tissue reflected by elevated pleural effusion volume, lung edema, BALF polymorphonuclear leukocytes count and lung myeloperoxidase levels, which was attenuated by pinitol (10 and 20 mg/kg) administration. Pinitol also markedly (P < .05) inhibited LPS-induced alterations in electrocardiographic, hemodynamic changes, right ventricular, and lung function tests. The LPS-induced downregulated nuclear factor erythroid 2-related factor 2 (Nrf-2) and heme oxygenase-1 (HO-1), whereas upregulated transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3), and inducible nitric oxide synthase (iNOs) lung messenger RNA expressions were significantly (P < .05) inhibited by pinitol. Western blot analysis suggested pinitol markedly (P < .05) decreased nuclear factor-κB (NF-κB), inhibitor of nuclear factor κB (IkBα), toll-like receptor 4 (TLR-4), and cyclooxygenase-II (COX-II) protein expressions in the lung. These findings were further supported by histological and ultrastructural analyses of lung tissue that show pinitol significantly (P < .05) ameliorates LPS-induced aberrations in lung tissue. In conclusion, pinitol attenuated LPS-induced pneumonia via inhibition of TLR-4 to downregulate the NF-κB/IκBα signaling cascade and thus ameliorated the production of proinflammatory cytokines (TNF-α, ILs, NLRP3, and TGF-β), inflammatory mediators (COX-II and iNOs) and elevated oxidative stress (Nrf-2 and HO-1).

Fan Y ，Wang J ，Feng Z ，Cao K ，Xu H ，Liu J ... -  《-》

Kegan Liyan oral liquid ameliorates lipopolysaccharide-induced acute lung injury through inhibition of TLR4-mediated NF-κB signaling pathway and MMP-9 expression.

Kegan Liyan oral liquid (KGLY), a Chinese prescription modified from classic formulas Yin-Qiao-San (from TCM classic Wenbing Tiaobian) and Shen-Jie-San (first mentioned in Shanghan Wenyi Tiaobian), has been reported to exert heat-clearing and detoxifying effects and used extensively for the treatment of severe pulmonary diseases in clinics including influenza, cough and pneumonia. The purpose of this study was to investigate the protective effect of KGLY on lipopolysaccharide (LPS) induced acute lung injury (ALI) in mice and to illuminate the underlying mechanisms. Mice were orally administrated with KGLY (50, 100 and 150mg/kg) before intratracheal instillation of LPS. 24h post LPS challenge, lung tissues and the bronchoalveolar lavage fluid (BALF) were collected for lung wet/dry (W/D) weight ratio, histopathological examinations and biochemical analyses. The cell counts, protein concentration, interleukin-1β (IL-1β), interleukin-6 (IL-6), necrosis factor-α (TNF-α), macrophage inflammatory protein-2 (MIP-2) in BALF, superoxide dismutase (SOD), glutathione (GSH), myeloperoxidase (MPO) and malondialdehyde (MDA) levels were detected. Meanwhile, the activation of toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), as well as matrix metalloproteinases 9 (MMP-9) were determined by western blot assay. KGLY significantly prolonged mice survival time and ameliorated LPS-induced edema, thickening of alveolar septa and inflammatory cell infiltration in a dose-dependent manner. Additionally, KGLY markedly attenuated LPS-induced acute pulmonary inflammation via decreasing the expressions of cytokines and chemokines (IL-1β, IL-6, TNF-α, and MIP-2), enhanced the activities of anti-oxidative indicators (SOD and GSH), suppressed the levels of MPO and MDA, and down-regulated the expressions of TLR4, NF-κB and MMP9. The results suggested that the relieving effect of KGLY against LPS-induced ALI might be partially due to suppression of oxidative stress and inflammatory response, inhibition of TLR4-mediated NF-κB activation, and down-regulation of MMP9 expression, indicating it may be a potential therapeutic agent for ALI.

Zhang X ，Sun CY ，Zhang YB ，Guo HZ ，Feng XX ，Peng SZ ，Yuan J ，Zheng RB ，Chen WP ，Su ZR ，Huang XD ... -  《-》

23-O-acetylshengmanol-3-O-α-L-arabinoside alleviates lipopolysaccharide-induced acute lung injury through inhibiting IκB/NF-κB and MAPK/AP-1 signaling pathways.

Cimicifuga foetida L. is a well-established traditional Chinese medicine with heat-clearing and detoxifying effects and has good therapeutic effect on oral mucosal ulcer and pharyngitis. The rhizome of this herb is rich in triterpenoid glycosides, including 23-O-acetylshengmanol-3-o-α-L-arabinoside (DA). Whether and how DA attenuates acute lung injury (ALI) are unclear. Accordingly, we focused on its anti-inflammatory effects and underlying molecular mechanisms in lipopolysaccharide (LPS)-stimulated ALI mice and RAW264.7 cells. The model of ALI mice was established by exposed intratracheal instillation of LPS. Lung pathological changes were evaluated by hematoxylin and eosin staining. Pulmonary function was assessed by whole-body plethysmography. Total protein content in bronchoalveolar lavage fluid (BALF) was detected by bicinchoninic acid method. Wet/dry lung ratio was used to evaluate the degree of pulmonary edema in mice. The levels of pro-inflammatory mediators were measured using enzyme-linked immunosorbent assay. The relative expression of pro-inflammatory gene mRNA was examined by RT-qPCR. The expression of inflammatory-related proteins was detected by Western blot. RAW264.7 cells were used to test the anti-inflammatory effects of DA in vitro. Cytotoxicity was assessed using a MTT assay. Nitric oxide production was measured by Griess assay. The production and expression of inflammatory mediators and the protein levels of inflammatory signaling molecules in the NF-κB and MAPK pathways were measured. Furthermore, immunofluorescence staining was used to analyze the expression of p-IκBα, p-ERK, and p-p38 in lung macrophages and the nuclear translocation of NF-κB p65 and AP-1 in cells. DA evidently alleviated histopathological changes and ameliorated pulmonary edema. Moreover, DA could reduce excessive inflammatory reaction in lung tissue as manifested by the reduction of proinflammatory mediators (IL-1β, IL-6, TNF-α, MCP-1, iNOS, and COX-2) in BALF, serum, and lung tissues. Further, DA inhibited the activation of the NLRP3/caspase-1 pathway in the lung. DA reduced the production and expression of the proinflammatory mediators above in RAW264.7 cells. Mechanistically, DA remarkably blocked the nuclear translocation of NF-κB p65, suppressed IκBα phosphorylation, and markedly reduced the nuclear translocation of AP-1 and the phosphorylation of ERK and p38. The findings demonstrated that DA exerts anti-inflammatory effects in LPS-stimulated ALI mice and macrophages by downregulating the NLRP3/caspase-1 signaling pathway in lung tissue and the IκB/NF-κB and MAPKs/AP-1 pathways in macrophages, suggesting that DA may be promising in ALI treatment.

Chen C ，Li L ，Liu X ，Zhang D ，Liu Y ，Li Y ... -  《-》

Galgeun-tang Attenuates Cigarette Smoke and Lipopolysaccharide Induced Pulmonary Inflammation via IκBα/NF-κB Signaling.

Shin NR ，Kim C ，Seo CS ，Ko JW ，Cho YK ，Shin IS ，Kim JS ... -  《MOLECULES》

Dexmedetomidine attenuates lipopolysaccharide induced acute lung injury in rats by inhibition of caveolin-1 downstream signaling.

Toll-like receptor 4(TLR-4)/nuclear factor-kappa B(NF-κB) pathway plays an important role in inducing acute lung injury (ALI). Studies have proved Dexmedetomidine (Dex) inhibits inflammatory response to mitigate lipopolysaccharide (LPS)-induced ALI and protect against multiorgan injury in various scenarios via restraining TLR-4/NF-κB signaling pathway. Many of the known downstream molecules have been orientated with a protein caveolin-1(Cav-1), which is supposed to take part in regulating TLR4-mediated inflammatory responses. However, its mechanisms have not been confirmed. The aim of this study is to evaluate the protective effects and potential mechanisms of Dex against LPS-induced ALI in male rats. Male rats received tail-vein injection of LPS to form ALI model. Rats were administrated with intraperitoneal injection Dex0.5 h before ALI. At 6 h after LPS injection, bronchoalveolar lavage fluid (BALF) and lung tissue were harvested. We stained the lung tissue sections with hematoxylin eosin (HE) staining to observe the histopathological damage and measure the ALI pathology score. We also measured the wet-to-dry(W/D) weight ratio of lung tissue. Lung myeloperoxidase (MPO) and inflammatory cytokines in the BALF were detected by Enzyme-linked immunosorbent assay(ELISA). Protein levels of Cav-1, TLR-4 and NF-κB in lung tissue were tested by immunohistochemistry method. The mRNA expression of Cav-1, TLR4 and the NF-κB in lung tissue were measured to determine the related mechanisms by quantitative real-time polymerase chain reaction(RT-PCR). It was indicated that Dex pretreatment markedly mitigated pathomorphologic changes and pathological lung injury scores. Besides, Dex pretreatment obviously decreased the W/D weight ratio of lung tissue, attenuated MPO activity significantly, along with LPS-stimulated augment of lung inflammatory cells infiltration in BALF. Moreover, compared with LPS model group, Dex pretreatment apparently increased the protein levels of Cav-1 downregulated by sepsis and decreased the protein levels of TLR-4 and NF-κB in lung tissue. Furthermore, Dex pretreatment apparently upregulated the expression of Cav-1 mRNA, restrained TLR4 and NF-κB mRNA. Dex pretreatment protects against LPS-induced ALI via inhibiting the activation of the TLR-4/NF-kB signaling pathway by upregulating the expression of Cav-1 downregulated by sepsis.

Liu J ，Huang X ，Hu S ，He H ，Meng Z ... -  《-》