Hepatoprotective Effects of the Polysaccharide Isolated from Tarphochlamys affinis (Acanthaceae) against CCl(4)-Induced Hepatic Injury

This study was designed to investigate the protective effects of the polysaccharide isolated from Tarphochlamys affinis (PTA) against CCl(4)-induced hepatotoxicity in rats. Liver injury was induced in rats by the administration of CCl(4) twice a week for 2 weeks. During the experiment, the model group received CCl(4) only; the treatment groups received various drugs plus CCl(4), whereas the normal control group received an equal volume of saline. Compared with the CCl(4) group, PTA significantly decreased the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) in the serum and increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) in the liver. Moreover, the content of hepatic malondialdehyde (MDA) was reduced. Histological findings also confirmed the anti-hepatotoxic characterisation. In addition, PTA significantly inhibited the proinflammatory mediators, such as prostaglandin E(2) (PGE(2)), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and myeloperoxidase (MPO). Further investigation showed that the inhibitory effect of PTA on the pro-inflammatory cytokines was associated with the down-regulation of nuclear factor-kappa B (NF-κB). In brief, our results show that the protective effect of PTA against CCl(4)-induced hepatic injury may rely on its ability to reduce oxidative stress and suppress inflammatory responses.     

Hepatoprotective effects of zingerone on carbon tetrachloride- and dimethylnitrosamine-induced liver injuries in rats

In this study, we investigated the hepatoprotective and anti-fibrotic effects of zingerone, one of the active components of ginger, against carbon tetrachloride (CCl₄)- and dimethylnitrosamine (DMN)-induced liver injuries in rats, respectively. Oral administration of zingerone (10 mg/kg) reduced CCl₄-induced abnormalities in liver histology, serum alanine aminotransferase and aspartate aminotransferase levels, and liver malondialdehyde levels. Zingerone treatment attenuated CCl₄-induced increases in inflammatory mediators, including tumor necrosis factor-α, interleukin-1β, cyclooxygenase-2, and inducible nitric oxide synthase mRNA levels. Western blot analysis showed that zingerone suppressed activation of nuclear factor-kappa B (NF-κB) p65 and phosphorylation of extracellular signal-regulated kinase, c-Jun NH₂-terminal kinase, and p38 mitogen-activated protein kinases (MAPKs). Liver fibrosis induced by DMN (10 mg/kg, intraperitoneally) was ameliorated by administration of zingerone (10 and 20 mg/kg, orally). Zingerone treatment reduced DMN-induced elevation of hydroxyproline content and hepatic stellate cell activation. In conclusion, zingerone showed antioxidative and anti-inflammatory effects in CCl₄-intoxicated rats by inhibiting oxidative stress and NF-κB activation via blockade of the activation of upstream MAPKs. Moreover, zingerone had hepatoprotective and anti-fibrotic effects against DMN-induced liver injury suggesting its usefulness in the prevention of liver inflammation and the development of hepatic fibrosis.     

Antifibrotic effect of meloxicam in rat liver: role of nuclear factor kappa B,proinflammatory cytokines,and oxidative stress

This study was aimed at investigating the antifibrotic effect of meloxicam in CCl4-induced liver fibrosis and elucidating its underlying mechanism. Forty male rats were equally randomized for 8-week treatment with corn oil (negative control), CCl4 (to induce liver fibrosis), and/or meloxicam. Meloxicam effectively ameliorated the CCl4-induced alterations in liver histology, liver weight to body weight ratio, liver functions, and serum markers for liver fibrosis (hyaluronic acid, laminin, and PCIII). Meloxicam significantly abrogated CCl4-induced elevation of messenger RNA (mRNA) expressions for collagen I and alpha smooth muscle actin (α-SMA) and hepatic contents of hydroxyproline, transforming growth factor beta (TGF-β), and tissue inhibitor of matrix metalloproteases (TIMP-1). Meloxicam mitigated CCl4-induced elevation in hepatic levels of nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α), total nitric oxide (NO), interleukin-l beta (IL 1β), and prostaglandin E2 (PGE2). Meloxicam modulated CCl4-induced disturbance of liver cytochrome P450 subfamily 2E1 (CYP2E1) and glutathione-S-transferase (GST). The attenuation of meloxicam to liver fibrosis was associated with suppression of oxidative stress via reduction of lipid peroxides along with induction of reduced glutathione content and enhancement of superoxide dismutase, glutathione peroxidase, and catalase activities. This study provides an evidence for antifibrotic effect of meloxicam against CCl4-induced liver fibrosis in rat. The antifibrotic mechanism of meloxicam could be through decreasing NF-κB level and subsequent proinflammatory cytokine production (TNF-α, NO, IL-1 beta, and PGE2) and, hence, collagen deposition through inhibition of TIMP-1 and TGF-β. Abrogation of oxidative stress and modulation of liver-metabolizing enzymes (CYP2E1 and GST) were also involved.     

Anthocyanins from purple sweet potato attenuate dimethylnitrosamine-induced liver injury in rats by inducing Nrf2-mediated antioxidant enzymes and reducing COX-2 and iNOS expression

Anthocyanins of the purple sweet potato exhibit antioxidant and hepatoprotective activities via a multitude of biochemical mechanisms. However, the signaling pathways involved in the actions of anthocyanin-induced antioxidant enzymes against chronic liver injury are not fully understood. We examined whether an anthocyanin fraction (AF) from purple sweet potato may prevent dimethylnitrosamine (DMN)-induced liver injury by inducing antioxidants via nuclear erythroid 2-related factor 2 (Nrf2) pathways and by reducing inflammation. Treatment with AF attenuated the DMN-induced increased serum alanine aminotransferase and aspartate aminotransferase activities. It also prevented the formation of hepatic malondialdehyde and the depletion of glutathione and maintained normal glutathione-S-transferase (GST) activity in the livers of DMN-intoxicated rats. Furthermore, AF increased the expression of Nrf2, NADPH:quinine oxidoreductase-1, heme oxygenase-1, and GSTα, which were reduced by DMN, and decreased the expression of cyclooxygenase-2 and inducible nitric oxide synthase. An increase in the nuclear translocation of nuclear factor kappa B (NF-κB) was observed in the DMN-induced liver injury group, but AF inhibited this translocation. Taken together, these results demonstrate that AF increases the expression of antioxidant enzymes and Nrf2 and at the same time decreases the expression of inflammatory mediators in DMN-induced liver injury. These data imply that AF induces antioxidant defense via the Nrf2 pathway and reduces inflammation via NF-κB inhibition.     

The involvement of Nrf2 in the protective effects of diallyl disulfide on carbon tetrachloride-induced hepatic oxidative damage and inflammatory response in rats

This study investigated the potential effect of diallyl disulfide (DADS) against carbon tetrachloride (CCl₄)-induced oxidative hepatic damage and inflammatory response in rat liver. DADS at doses of 50 and 100 mg/kg/day was administered orally once daily for 5 days, prior to CCl₄ administration. Pretreatment with DADS attenuated CCl₄-induced elevated serum transaminase activities and histopathological alterations in liver. It prevented the hepatocellular apoptotic changes with induction of Bcl-2-associated X (Bax), cytochrome c, and caspase-3 caused by CCl₄. An increase in the nuclear translocation of nuclear factor-kappaB (NF-κB) and phosphorylation of I kappaB alpha (IκBα) was observed in the livers of CCl₄-treated rats that coincided with induction of inflammatory mediators or cytokines. In contrast, DADS inhibited NF-κB translocation and IκBα phosphorylation, and that subsequently decreased inflammatory mediators. Furthermore, DADS prevented CCl₄-induced depletion of cytosolic nuclear factor E2-related factor 2 (Nrf2) and suppression of nuclear translocation of Nrf2, which, in turn, up-regulated phase II/antioxidant enzyme activities. Taken together, these results demonstrate that DADS increases the expression of phase II/antioxidant enzymes and simultaneously decreases the expression of inflammatory mediators in CCl₄-induced liver injury. These findings indicate that DADS induces antioxidant defense mechanism by activating Nrf2 pathway and reduces inflammatory response by inhibiting NF-κB activation.     

滨蒿内酯对四氯化碳致小鼠急性肝损伤的保护作用研究

目的:研究滨蒿内酯对四氯化碳(CCl4)致小鼠急性肝损伤的保护作用及潜在分子机制.方法:将50只雄性昆明种小鼠随机分为正常对照组、模型组、水飞蓟素组(阳性对照,120 mg/kg)和滨蒿内酯高、低剂量组(60、30 mg/kg),每组10只.各给药组小鼠均灌胃相应药物,正常对照组和模型组小鼠灌胃等体积0.5％羧甲基纤维...     

Resveratrol preconditioning protects hepatocytes against hepatic ischemia reperfusion injury via Toll-like receptor 4/nuclear factor-κB signaling pathway in vitro and in vivo

The purpose of this study was to investigate the protective effect of resveratrol against hepatic ischemia reperfusion injury (HIRI) and explore the potential underlying mechanism. Resveratrol-pretreated BRL-3A (rat liver) cells and rats underwent hypoxia/reoxygenation and hepatic ischemia/reperfusion, respectively. BRL-3A cell damage was evaluated, and the mRNA and protein expression of related signal molecules was assessed in cell model. The protein expression of related signal molecules was also assessed in rat model. Inflammatory cytokines levels were determined in the cell supernatant and rat serum while rat liver function and hepatocyte apoptosis were assessed. The results revealed that resveratrol significantly enhanced cell viability, inhibited cell apoptosis, and decreased levels of lactate dehydrogenase (LDH) and production of tumor necrosis factor-α (TNF-α) and interleukin-(IL)-1β in the cell supernatant. In addition, resveratrol ameliorated elevated Toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB, and the depressed inhibitor of NF-κB (IκB)-α caused by hypoxia/reoxygenation stimulation in BRL-3A cells. Moreover, resveratrol inhibited the translocation of NF-κB p65 after the stimulation of hypoxia/reoxygenation in BRL-3A cells. In vivo assays revealed that resveratrol reduced levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and liver pathological changes, while it alleviated hepatocyte apoptosis, negatively mediated the production of TNF-α and IL-1β in serum, and reversed TLR4/NF-κB signaling pathway caused by hepatic ischemia/reperfusion stimulation in liver tissues. The results indicate that resveratrol protected hepatocytes against HIRI, which may be mediated in part via the TLR4/NF-κB signaling pathway.     

Didymin ameliorates hepatic injury through inhibition of MAPK and NF-κB pathways by up-regulating RKIP expression

A flavone was isolated from Origanum vulgare and identified as didymin (O. vulgare didymin, OVD). The protective effect and mechanism of OVD on acute liver injury was then assessed in vivo and in vitro. Our results showed that OVD significantly alleviated CCl₄-induced liver injury in mice and markedly decreased serum ALT and AST activities. OVD treatment significantly reduced CYP2E1 activity, lipid peroxidation level, ROS generation, NO production and pro-inflammatory cytokines (such as TNF-α, IL-6 and IL-1β) in liver tissues and RAW 264.7 cells, but enhanced the hepatic antioxidative enzymes activities. Further study showed that OVD significantly inhibited the NF-κB and MAPK pathways. Interestingly, OVD notably enhanced Raf kinase inhibitor protein (RKIP) expression, and the effects of OVD on histological changes, oxidative stress and inflammation was largely abolished by the RKIP specific inhibitor locostatin. Our findings indicate that OVD can ameliorate CCl₄-induced liver injury, which may be ascribed to its radical scavenging action, antioxidant activity, and modulation of MAPK and NF-κB signaling pathways.     

Effects of salvianolic acid a on oxidative stress and liver injury induced by carbon tetrachloride in rats

In the present study, we investigated the hepatoprotective effects of salvianolic acid A, a novel antioxidant, against oxidative stress and acute liver injury induced by carbon tetrachloride (CCl(4)) in rats, and the mechanisms underlying its protective effects. Administration of CCl(4) to rats caused severe hepatic damage, as demonstrated by the significant increase in the levels of serum alanine aminotransferase, aspartate aminotransferase and classic histological changes including hepatocyte necrosis or apoptosis, haemorrhage, fatty degeneration, etc. Co-treatment with salvianolic acid A (20 mg/kg, intraperitoneally), a water-soluble extract from a Chinese traditional drug, Radix Salvia miltiorrhiza, significantly decreased CCl(4)-induced hepatotoxicity. Salvianolic acid A not only decreased serum alanine aminotransferase, aspartate aminotransferas levels and ameliorated histopathological manifestations in CCl(4)-treated rats, but also reduced oxidative stress, as evidenced by decreased reactive oxygen species production and malondialdehyde concentrations in the liver tissues, combined with elevated hepatic superoxide dismutase activity and gluthathione content. In addition, salvianolic acid A treatment remarkably reduced intrahepatic tumour necrosis factor-alpha concentrations and caspase-3 activities as compared with the CCl(4)-treated rats. The results suggested that treatment with salvianolic acid A provides a potent protective effect against acute hepatic damage caused by CCl(4) in rats, which may mainly be related to its antioxidative effect.     

丹参多酚酸盐对肝纤维化大鼠NF-κB和IκBα表达的影响

目的观察丹参多酚酸盐的抗肝纤维化作用及其机制。方法将36只SD大鼠随机分为正常对照组、模型组和给药组。50%CCl_4花生油溶液(1 mL·kg~(-1))灌胃诱导建立肝纤维化模型。给药组同时每日一次腹腔注射丹参多酚酸盐20 mg·kg~(-1)。6 wk后观察大鼠肝脏大体形态、肝重-体重比;运用HE和Masson三色染色检测肝纤维化的变化;全自动生化分析仪检测丙氨酸转氨酶(ALT)及天冬氨酸转氨酶(AST);放射免疫法测定血清Ⅳ型胶原(CIV)、层黏蛋白(LN)含量;Western blot检测肝脏组织中NF-κB和IκBα蛋白的表达。结果与模型组相比,给药组肝纤维化大鼠肝脏病理组织学结构改善,血清中ALT、AST、CIV、LN表达降低(P<0.05)。与模型组相比,给药组胞质中NF-κB和lκBα蛋白的表达上调,胞核中NF-κB蛋白表达下调(P<0.01)。结论丹参多酚酸盐可通过调节大鼠肝脏NF-κB和lκBα的表达来抑制肝纤维化的进展     

Hepatoprotective effects of total saponins isolated from Taraphochlamys affinis against carbon tetrachloride induced liver injury in rats

In this study, rats were orally treated with the total saponins of Taraphochlamys affinis (TSTA) daily with administration of CCl4 twice a week for 8 weeks. Compared to the normal control, CCl4 induced liver damage significantly increased the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in serum and decreased the activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and glutathione reductase (GSH-Rd) in liver. Meanwhile content of hepatic malondialdehyde (MDA), which was oxidative stress marker, was increased. Histological finding also confirmed the hepatotoxic characterization in rats. Furthermore, proinflammatory mediators including tumor necrosis factor-α(TNF-α) in serum, prostaglandin E2 (PGE2), inducible enitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in liver were detected with elevated contents, while expression of xenobiotic metabolizing enzyme--cytochrome P4502E1 (CYP2E1) was inhibited. The results revealed that TSTA not only significantly reversed CCl4 originated changes in serum toxicity and hepatotoxic characterization, but also altered expression of hepatic oxidative stress markers and proinflammatory mediators, combined with restoring liver CYP2E1 level. The results indicated that protective effect of TSTA against CCl4-induced hepatic injury may rely on its effect on reducing oxidative stress, suppressing inflammatory responses and improving drug-metabolizing enzyme activity in liver.     

钝化NF-κB的活化对酒精性肝损伤大鼠CYP3A的影响

目的研究核转录因子-κB(nuclear fastor kappa B,NF-κB)在酒精性肝损伤大鼠模型中的作用及对细胞色素P4503A(cytochrome P450 3A,CYP3A)代谢活力的影响。方法采用白酒灌胃法复制大鼠酒精性肝损伤模型,肝脏组织HE染色和血清中ALT和AST水平测定观测大鼠肝损伤情况,采用免疫组化法检测肝脏NF-κB的蛋白表达,通过HPLC法检测CYP3A的探针药物咪哒唑仑的血浆药物浓度,采用热板法观察大鼠舔足反应来体现咪哒唑仑的代谢情况,从而反映咪哒唑仑特异性代谢酶CYP3A的代谢活力。结果酒精性肝损伤模型组表现为轻度脂肪变性和炎症坏死,NF-κB明显活化,CYP3A代谢活力增强(P<0.05);钝化NF-κB的活化后,肝脏脂肪变性程度明显减轻,CYP3A代谢活力下调(P<0.05)。结论钝化NF-κB活化,可以减轻酒精性肝损伤的程度,并下调酒精性肝损伤导致的CYP3A代谢活性的增强。     

Protective effect of saponins derived from the roots of Platycodon grandiflorum against carbon tetrachloride induced hepatotoxicity in mice

The purpose of this study was to investigate the protective effects of the saponins isolated from the root of Platycodi Radix (Changkil saponins: CKS) on carbon tetrachloride (CCl(4))-induced hepatotoxicities in mice. Pretreatment with CKS prior to the administration of CCl(4) significantly prevented the increase in serum alanine aminotransferase and aspartate aminotransferase activities and hepatic lipid peroxidation formation. In addition, CKS prevented CCl(4)-induced apoptosis and necrosis, as indicated by a liver histopathologic study and DNA laddering. To determine whether Fas/Fas ligand (FasL) pathway involved in CCl(4)-induced acute liver injury, Fas and FasL proteins and caspase-3, -8 activities were tested by western blotting and ELISA. CKS markedly decreased CCl(4)-induced Fas/FasL protein expression levels and in turn attenuated CCl(4)-induced caspase-3, -8 activities in mouse livers. Additionally, CKS protected the CCl(4)-induced depletion of hepatic glutathione levels. The effect of CKS on CYP2E1, the major isozyme involved in CCl(4) bioactivation, was investigated. Treatment with CKS resulted in a significant decrease in the CYP2E1-dependent hydroxylation of aniline. In addition, CKS exhibited antioxidant effects on FeCl(2)-ascorbate induced lipid peroxidation in liver homogenates, and on superoxide radical scavenging activity. These findings suggest that the protective effects of CKS against CCl(4)-induced acute liver injury possibly involve mechanisms related to its ability to block CYP2El-mediated CCl(4) bioactivation and its free radical scavenging effects, and that is also protects against Fas/FasL pathway mediated apoptosis.     

Protective effects of total flavonoids of Bidens bipinnata L. against carbon tetrachloride-induced liver fibrosis in rats

Bidens bipinnata L. is well known in China as a traditional Chinese medicine and has been used to treat hepatitis in clinics for many years. In a previous study we found that total flavonoids of Bidens bipinnata L. (TFB) had a protective effect against carbon tetrachloride (CCl4)-induced acute liver injury in mice. Now this study was designed to investigate its therapeutic effect against CCl4-induced liver fibrosis in rats and to determine, in part, its mechanism of action. The liver fibrosis model was established by subcutaneous injection of 50% CCl4 twice a week for 18 weeks. TFB (40, 80 and 160 mg kg(-1)) was administered by gastrogavage daily from the 9th week. The results showed that TFB (80 and 160 mg kg(-1)) treatment for 10 weeks significantly reduced the elevated liver index (liver weight/body weight) and spleen index (spleen weight/body weight), elevated levels of serum transaminases (alanine aminotransferase and aspartate aminotransferase), hyaluronic acid, type III procollagen and hepatic hydroxyproline. In addition, TFB markedly inhibited CCl4-induced lipid peroxidation and enhanced the activity of the antioxidant enzymes superoxide dismutase and glutathione peroxidase. Moreover, TFB (80 and 160 mg kg(-1)) treatment improved the morphologic changes of hepatic fibrosis induced by CCl4 and suppressed nuclear factor (NF)-kappaB, alpha-smooth muscle actin (SMA) protein expression and transforming growth factor (TGF)-beta1 gene expression in the liver of liver fibrosis of rats. In conclusion, TFB was able to ameliorate liver injury and protect rats from CCl4-induced liver fibrosis by suppressing oxidative stress. This process may be related to inhibiting the induction of NF-kappaB on hepatic stellate cell activation and the expression of TGF-beta1.     

清开灵注射液对四氯化碳致小鼠急性肝损伤的保护机制研究

目的：观察清开灵注射液对小鼠急性肝损伤的保护作用,并阐明其可能机制.方法：建立小鼠CCl4急性肝损伤模型,观察清开灵注射液对CCl4诱导升高的小鼠血清ALT、AST活性影响,及对肝脏病理损伤的保护作用;测定肝组织中丙二醛（MDA）含量及超氧化物歧化酶（SOD）活性.结果：与阴性对照组比较,模型组小鼠ALT和AST均显著升高（P＜0.01）,MDA明显增加（P＜0.01）,SOD显著降低（P＜0.01）,组织病理损伤明显.与模型组比较,清开灵注射液中剂量组（10 ml·kg^-1）和高剂量组（20 ml·kg^-1）均能显著降低肝损伤小鼠的ALT和AST（P ＜0.05 或0.01）,并明显减轻了肝脏组织的病理损伤.清开灵注射液低剂量组（5 ml· kg^-1）、中剂量组和高剂量组的MDA均较模型组显著降低（P＜O.05或0.01）,SOD水平则显著升高（P＜0.05或0.01）.结论：清开灵注射液对小鼠CCl4致急性肝损伤的保护作用可能与其抗脂质过氧化作用有关.     

Rosmarinic acid attenuates hepatic ischemia and reperfusion injury in rats

Rosmarinic acid (RosmA) demonstrates antioxidant and anti-inflammatory properties. We investigated the effect of RosmA on liver ischemia/reperfusion injury. Rats were submitted to 60 min of ischemia plus saline or RosmA treatment (150 mg/kg BW intraperitoneally) followed by 6 h of reperfusion. Hepatocellular injury was evaluated according to aminotransferase activity and histological damage. Hepatic neutrophil accumulation was also evaluated. Oxidative/nitrosative stress was estimated by measuring the reduced glutathione, lipid hydroperoxide and nitrotyrosine levels. Endothelial and inducible nitric oxide synthase (eNOS/iNOS) and nitric oxide (NO) were assessed with immunoblotting and chemiluminescence assays. Hepatic tumor necrosis factor-alpha (TNF-α) and interleukin-1beta mRNA were assessed using real-time PCR, and nuclear factor-kappaB (NF-κB) activation was estimated by immunostaining. RosmA treatment reduced hepatocellular damage, neutrophil infiltration and all oxidative/nitrosative stress parameters. RosmA decreased the liver content of eNOS/iNOS and NO, attenuated NF-κB activation, and down-regulated TNF-α and interleukin-1beta gene expression. These data indicate that RosmA exerts anti-inflammatory and antioxidant effects in the ischemic liver, thereby protecting hepatocytes against ischemia/reperfusion injury. The mechanisms underlying these effects may be related to the inhibitory potential of RosmA on the NF-κB signaling pathway and the reduction of iNOS and eNOS expressions and NO levels, in addition to its natural antioxidant capability.     

Chlorogenic acid reduces liver inflammation and fibrosis through inhibition of toll-like receptor 4 signaling pathway

Chlorogenic acid (CGA) is a type of polyphenol with anti-inflammatory, antioxidant activities. Our previous studies showed CGA could efficiently inhibit carbon tetrachloride (CCl₄)-induced liver fibrosis in rats. However, the specific underlying mechanism remains unclear. The aim of this study is to investigate the effects of CGA on liver inflammation and fibrosis induced by CCl₄ and whether they are related to inhibition of toll-like receptor 4 (TLR4) signaling pathway. Male Sprague-Dawley (SD) rats were administrated CCl₄ together with or without CGA for 8 weeks. Histopathological and biochemical analyses were carried out. The mRNA and protein expression levels of proinflammatory and profibrotic mediators were detected by RT-PCR and Western blot, respectively. The levels of serum proinflammatory cytokines were detected by ELISA. CGA significantly attenuated CCl₄-induced liver damage and symptoms of liver fibrosis, accompanied by reduced serum transaminase levels, collagen I and α-smooth muscle actin (α-SMA) expression. As compared with the CCl₄-treated group, the expression levels of TLR4, myeloid differentiation factor 88 (MyD88), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were reduced in the treatment group of CCl₄ and CGA, whereas bone morphogenetic protein and activin membrane-bound inhibitor (Bambi) expression was increased. CGA also suppressed CCl₄ induced nuclear factor-κB (NF-κB) activation. Moreover, the hepatic mRNA expression and serum levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were significantly increased in CCl₄-treated rats and attenuated by co-treatment with CGA. Our data indicate that CGA can efficiently inhibit CCl₄-induced liver fibrosis in rats and the protective effect may be due to the inhibition of TLR4/MyD88/NF-κB signaling pathway.     

鬼针聚炔苷对CCl4诱导的小鼠急性肝损伤的保护作用

目的研究鬼针聚炔苷(BPC)对CCl4诱导的小鼠急性肝损伤的保护作用。方法腹腔注射0.2%CCl4橄榄油溶液建立小鼠急性肝损伤模型,以水飞蓟素为阳性对照,鬼针聚炔苷(12.5、25、50 mg.kg-1)灌胃给药6 d,测定各组小鼠血清中丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)的含量;检测肝组织匀浆中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)的活性和丙二醛(MDA)、一氧化氮(NO)的含量;同时计算肝指数、并对肝组织进行病理组织学检查,免疫组化学法观察NF-κB p65在肝组织中的表达。结果与模型组比较,鬼针聚炔苷能够显著降低血清ALT、AST的含量;提高肝组织中SOD、GSH-Px的水平,降低MDA、NO的含量;能明显改善肝细胞变性和坏死;可以显著减少NF-κBP65的表达。结论 BPC对CCl4所致小鼠急性肝损伤有保护作用,其机制可能与抗脂质过氧化、抑制NO产生及抑制NF-κB表达等有关。     

Dihydropyranoaurone compound damaurone D inhibits LPS-induced inflammation and liver injury by inhibiting NF-κB and MAPK signaling independent of AMPK

Recently, we reported the synthesis of damaurone D (DD), originally derived from Rosa damascene, and its anti-inflammatory effect in macrophages. Here, we investigated the molecular mechanism underlying the anti-inflammatory effect of DD in macrophages and further tested whether DD is protective against lipopolysaccharide (LPS)-induced liver injury. DD inhibited LPS-stimulated expression of pro-inflammatory genes and cytokine/chemokine secretion in a concentration-dependent manner in RAW 264.7 cells and thioglycolate-elicited mouse peritoneal macrophages. DD suppressed LPS-stimulated nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, as demonstrated by reduction in IκB kinase α/β phosphorylation, IκBα degradation, and levels of phosphorylated ERK, JNK, and p38 MAPK. The luciferase reporter activity of NF-κB and activator protein 1 was also attenuated by DD pretreatment. Furthermore, DD treatment induced AMP-activated protein kinase (AMPK) activation in cells and mouse liver, although the anti-inflammatory effect of DD was similar in dominant-negative AMPK-overexpressing cells. Lastly, DD-treated mice were protected against LPS-induced acute liver injury, based on morphologic and immunohistochemical observations; reduction in the plasma levels of aspartate aminotransferase, TNF-α, and MCP-1; and a decrease in inflammatory gene expression. In summary, our findings indicate that DD can protect against LPS-stimulated inflammation and liver injury at least partly by suppression of NF-κB and MAPK signaling pathways.