Isochlorogenic acid A attenuates progression of liver fibrosis through regulating HMGB1/TLR4/NF-κB signaling pathways

OBJECTIVE Liver fibrosis is a chronic damage process related to the further progression of hepatic cirrhosis and has yet no truly effective treatment is available.This study aimed to investigate the effects of isochlorogenic acid A(ICQA)on liver fibrosis induced by carbon tetrachloride(CCl4)and clarify the underlying mechanism.METHODS Rats were treated with CCl4 for eight weeks in order to induce liver fibrosis and simultaneously orally administered with ICQA(10,20 and 40 mg·kg-1).RESULTS ICQA had significant protective effect on liver injury,inflammation,and fibrosis in rats.Meanwhile,ICQA prevented the activation of hepatic stellate cells(HSC)as indicated by inhibiting the overexpres⁃sion of a-smooth muscle actin(a-SMA).In addition,reduced fibrosis was found to be associated with decreased protein expression of high-mobility group box 1(HMGB1)and toll like receptor(TLR)4.Moreover,ICQA supressed the cytoplasmic translocation of HMGB1 in rat liver.Further investigations indicated that ICQA treatment significantly attenuated nuclear translocation of the nuclear factor-κB(NF-κB)p65 and inhibited degradation of IkBa expression in the liver of rats with liver fibrosis.CONCLUSION ICQA has hepatoprotective and anti-fibrotic effects in rats with liver fibrosis through modulating the HMGB1/TLR4/NF-κB signaling pathways.

Toll样受体4单克隆抗体对急性期溃疡性结肠炎小鼠结肠黏膜Toll样受体4介导的核因子-κB信号通路的影响

目的探讨Toll样受体4(TLR4)单克隆抗体(TLR4mAb)对葡聚糖硫酸钠(DSS)诱导的急性期溃疡性结肠炎(UC)小鼠肠黏膜TLR4介导的核因子(NF)-κB信号通路中磷酸化IκB激酶(p-IKK)及NF-κB的影响情况。方法30只BALB/c小鼠均分为正常对照组(A组)、UC模型组(B组)及低、中、高剂量TLR4mAb干预组(C、D、E组)。A组小鼠饮用蒸馏水7d;B、C、D、E组小鼠饮用5%DSS水溶液7d以制成UC模型。造模同时,C、D、E组小鼠分别腹腔注射低、中、高剂量TLR4mAb。造模及干预7d后处死小鼠,观察指标包括疾病活动指数(DAI)、结肠组织病理学评分(HPS)。采用Western印迹法检测各组肠黏膜p-IKK的蛋白表达,蛋白凝胶电泳迁移率变动分析法(EMSA法)检测NF-κB的活性变化。结果B组小鼠的结肠黏膜DAI及HPS均显著高于A组(P值均<0.01)。与模型组相比,使用TLR4mAb干预后中、高剂量组HPS有不同程度的缓解(P值均<0.01)。②与B组相比,D、E组的TLR4mAb后p-IKK表达及NF-κB的活性均显著下降(P值分别<0.05、0.01)。结论TLR4mAb可以减轻肠道炎症,发挥干预作用,其机制可能是通过抑制TLR4介导的NF-κB通路关键蛋白的表达,降低NF-κB的活性,继而减少下游炎性因子过度表达。

Catalpol ameliorates LPS-induced endometritis by inhibiting inflammation and TLR4/NF-κB signaling

Catalpol is the main active ingredient of an extract from Radix rehmanniae,which in a previous study showed a protective effect against various types of tissue injury.However,a protective effect of catalpol on uterine inflammation has not been reported.In this study,to investigate the protective mechanism of catalpol on lipopolysaccharide(LPS)-induced bovine endometrial epithelial cells(bEECs)and mouse endometritis,in vitro and in vivo inflammation models were established.The Toll-like receptor 4(TLR4)/nuclear factor-κB(NF-κB)signaling pathway and its downstream inflammatory factors were detected by enzyme-linked immunosorbent assay(ELISA),quantitative real-time polymerase chain reaction(qRT-PCR),western blot(WB),and immunofluorescence techniques.The results from ELISA and qRT-PCR showed that catalpol dose-dependently reduced the expression of pro-inflammatory cytokines such as tumor necrosis factorα(TNF-α),interleukin(IL)-1β,and IL-6,and chemokines such as C-X-C motif chemokine ligand 8(CXCL8)and CXCL5,both in bEECs and in uterine tissue.From the experimental results of WB,qRT-PCR,and immunofluorescence,the expression of TLR4 and the phosphorylation of NF-κB p65 were markedly inhibited by catalpol compared with the LPS group.The inflammatory damage to the mouse uterus caused by LPS was greatly reduced and was accompanied by a decline in myeloperoxidase(MPO)activity.The results of this study suggest that catalpol can exert an anti-inflammatory impact on LPS-induced bEECs and mouse endometritis by inhibiting inflammation and activation of the TLR4/NF-κB signaling pathway.

Modulating effects of Astragalus polysaccharide on immune disorders via gut microbiota and the TLR4/NF-κB pathway in rats with syndrome of dampness stagnancy due to spleen deficiency

The syndrome of dampness stagnancy due to spleen deficiency(DSSD)is relatively common globally.Although the pathogenesis of DSSD remains unclear,evidence has suggested that the gut microbiota might play a significant role.Radix Astragali,used as both medicine and food,exerts the effects of tonifying spleen and qi.Astragalus polysaccharide(APS)comprises a macromolecule substance extracted from the dried root of Radix Astragali,which has many pharmacological functions.However,whether APS mitigates the immune disorders underlying the DSSD syndrome via regulating gut microbiota and the relevant mechanism remains unknown.Here,we used DSSD rats induced by high-fat and low-protein(HFLP)diet plus exhaustive swimming,and found that APS of moderate molecular weight increased the body weight gain and immune organ indexes,decreased the levels of interleukin-1β(IL-1β),IL-6,and endotoxin,and suppressed the Toll-like receptor 4/nuclear factor-κB(TLR4/NF-κB)pathway.Moreover,a total of 27 critical genera were significantly enriched according to the linear discriminant analysis effect size(LEfSe).APS increased the diversity of the gut microbiota and changed its composition,such as reducing the relative abundance of Pseudoflavonifractor and Paraprevotella,and increasing that of Parasutterella,Parabacteroides,Clostridium XIVb,Oscillibacter,Butyricicoccus,and Dorea.APS also elevated the contents of short-chain fatty acids(SCFAs).Furthermore,the correlation analysis indicated that 12 critical bacteria were related to the body weight gain and immune organ indexes.In general,our study demonstrated that APS ameliorated the immune disorders in DSSD rats via modulating their gut microbiota,especially for some bacteria involving immune and inflammatory response and SCFA production,as well as the TLR4/NF-κB pathway.This study provides an insight into the function of APS as a unique potential prebiotic through exerting systemic activities in treating DSSD.

Therapeutic Effect of Crocin on Diabetic Retinopathy in Rats Based on TLR4/My D88/NF-κB Pathway

Objective:To study the therapeutic effect of crocin on diabetic retinopathy(DR)in rats based on toll-like receptor 4(TLR4)/myeloid differentiation factor 88(My D88)/nuclear factor-κB(NF-κB)pathway.Methods:Thirty SPF SD rats were used in the experiment,which were randomly divided into DR group,control group and crocin group,with 10 rats in each group.The DR rat model was established by feeding the rats in both the DR group and crocin group with a high glucose and high fat diet,along with intraperitoneal injection(IP)of streptozotocin.Crocin IP was administered to the rats in the crocin group,whereas the rats in the DR group and control group received an equivalent dosage of saline IP for 12 weeks.A comparison was made among the three groups regarding retinal thickness,vascular permeability,expression of TLR4/My D88/NF-κB pathway protein,levels of inflammatory factors,and levels of Bcl-2,Bax,and Bcl-2/Bax.Results:The DR group and crocins group exhibited a lower retinal thickness compared to the control group,while the crocins group displayed a higher thickness than the DR group.The DR group and crocins group had higher retinal vascular permeability than the control group,and the crocins group had lower retinal vascular permeability than the DR group(P<0.05).TLR4,My D88,and P-NF-κB relative expressions were higher in the DR and crocin groups than in the control group,whereas TLR4,My D88,and P-NF-κB relative expressions were lower in the crocin group than in the DR group(P<0.05).The DR group and crocin group exhibited elevated levels of inflammatory cytokines compared to the control group,while the crocin group displayed decreased levels in comparison to the DR group(P<0.05).The DR group and crocin group exhibited lower levels of Bcl-2 and Bcl-2/Bax compared to the control group,whereas the control group displayed higher levels of Bax.The crocin group exhibited elevated levels of Bcl-2 and Bcl-2/Bax compared to the DR group,whereas the DR group displayed diminished levels of Bax(P<0.05).Conclusion:Crocin has the potential to enhance the retinal thickness and vascular permeability of DR rats,and the inhibition of the TLR4/My D88/NF-κB pathway by crocin could play a crucial role in impeding the advancement of DR.