Preparation and effects of functionalized liposomes targeting breast cancer tumors using chemotherapy, phototherapy, and immunotherapy.

Breast cancer therapy has significantly advanced by targeting the programmed cell death-ligand 1/programmed cell death-1 (PD-L1/PD-1) pathway. BMS-202 (a smallmolecule PD-L1 inhibitor) induces PD-L1 dimerization to block PD-1/PD-L1 interactions, allowing the T-cell-mediated immune response to kill tumor cells. However, immunotherapy alone has limited effects. Clinically approved photodynamic therapy (PDT) activates immunity and selectively targets malignant cells. However, PDT aggravates hypoxia, which may compromise its therapeutic efficacy and promote tumor metastasis. We designed a tumor-specific delivery nanoplatform of liposomes that encapsulate the hypoxia-sensitive antitumor drug tirapazamine (TPZ) and the small-molecule immunosuppressant BMS. New indocyanine green (IR820)-loaded polyethylenimine-folic acid (PEI-FA) was complexed with TPZ and BMS-loaded liposomes via electrostatic interactions to form lipid nanocomposites. This nanoplatform can be triggered by near-infrared irradiation to induce PDT, resulting in a hypoxic tumor environment and activation of the prodrug TPZ to achieve efficient chemotherapy. The in vitro and in vivo studies demonstrated excellent combined PDT, chemotherapy, and immunotherapy effects on the regression of distant tumors and lung metastases, providing a reference method for the preparation of targeted agents for treating breast cancer.

Prognostic value of MTV and TLG of 18 F-FDG PET in patients with head and neck squamous cell carcinoma: A meta-analysis.

BACKGROUND: The current systematic review and meta-analysis explored the value of metabolic tumor volume (MTV) as well as total lesion glycolysis (TLG) in predicting the prognosis of head and neck squamous cell carcinoma (HNSCC) using 18 F-FDG PET parameters. METHODS: This work identified relevant studies in the English language by searching several electronic databases, like Cochrane Library, EMBASE, and PubMed. In addition, pooled hazard ratios (HRs) were also calculated to analyze whether MTV and TLG were significant in predicting prognosis. RESULTS: The present study included 15 primary studies involving HNSCC cases. As for the elevated TLG, it attained the pooled HR of 1.85 (95% confidence interval [CI], 1.16-2.94; P = .000; I2 = 78.3%) in predicting overall survival (OS), whereas that for elevated MTV was1.22 (95%CI, 1.09-1.36; P = .000; I2 = 82.4%). Besides, for elevated MTV, it attained the pooled HR of 1.34 (95%CI, 1.15-1.56, P = .000; I2 = 86.0%) in predicting disease-free survival (DFS); while the elevated TLG was related to DFS. Sensitivity analysis confirmed that our results are reliable. As for MTV, the ROC-stratified subgroups for DFS and multivariate analyses-stratified subgroups for OS showed statistically significant differences, with no obvious heterogeneities across different studies. For TLG, other methods-stratified subgroups for OS showed statistically significant differences, with no obvious heterogeneity across different studies. CONCLUSION: This work indicated that PET/CT is of predictive significance across HNSCC cases. Although the included articles used different methods and recruited HNSCC cases with high clinical heterogeneity; however, our findings confirmed that an elevated MTV can predict the increased risk of side reactions or even death among HNSCC cases and that an elevated TLG can predict a higher death risk.

Improved Antitumor Outcomes for Colon Cancer Using Nanomicelles Loaded with the Novel Antitumor Agent LA67.

BACKGROUND: LA67 is a derivative of triptolide that exhibits strong antitumor activity. This derivative has a better safety profile than triptolide, but is limited by poor aqueous solubility. AIM AND METHODS: To improve solubility and further increase therapeutic efficacy, we prepared LA67-loaded polymeric micelles (LA67-PMs) using a film hydration method. The physicochemical properties of LA67-PMs were investigated, and the antitumor activity of this formulation against Colon26 (C26) cancer cell line was evaluated in vitro and in vivo with LA67 as a control. RESULTS: Polymeric micelles containing LA67 had a particle size of 17.88 nm and a drug entrapment efficiency of 94.84%. This formulation dispersed completely in aqueous solution and exhibited slow, sustained release of LA67. Cellular uptake assay showed that LA67-PMs delivered LA67 to cancer cells with greater efficiency than free LA67, which resulted in increased LA67 accumulation in cancer cells. Cell counting kit 8 (CCK-8) assay showed that blank polymeric micelles (PMs) exhibited low toxicity and LA67-PMs exerted pronounced anti-proliferation effects against C26 cells. Furthermore, LA67-PMs induced apoptosis and repressed migration more effectively than free LA67. In vivo evaluation of antitumor activity showed that LA67-PMs inhibited tumor growth and distant organ metastasis to a greater extent than LA67, which resulted in improved survival rate. The potential mechanisms of these effects may have been induction of apoptosis, inhibition of cell proliferation, and neovascularization. CONCLUSION: Our study showed that LA67-PMs may be a promising formulation for treatment of colon cancer.

Hypoglycemic property of soy isoflavones from hypocotyl in Goto-Kakizaki diabetic rats.

The present study was carried out to investigate the hypoglycemic effect of soy isoflavones from hypocotyl in GK diabetic rats. A single administration and long-term administration tests were conducted in GK diabetic rats to test the hypoglycemic effect of soy isoflavones. At the end of long-term administration trial, blood protein, cholesterol, triglyceride, glycosylated serum protein, C-reactive protein, insulin, aminotransferase, lipid peroxide, interleukin-6, tumor necrosis factor-α were estimated. Inhibition of soy isoflavones against α-amylase and α-glucosidase, as well as on glucose uptake into brush border membrane vesicles or Caco-2 cells were determined in vitro. In single administration experiment, soy isoflavones reduced postprandial blood glucose levels in GK rats. In long-term administration, hypoglycemic effect of soy isoflavones was first observed at week 12 and maintained till week 16. A significant reduction in fasting blood glucose, C-reactive protein, and lipid peroxide was noted at week 16. However, there was no significant treatment effect on blood insulin. Furthermore, soy isoflavone administration resulted in significant decreases in glycosylated serum protein, tumor necrosis factor-α, and interleukin-6. Other biochemical parameters, such as protein, cholesterol, triglyceride and aminotransferases were not modified, however. The results in vitro showed that soy isoflavones showed a potent inhibitory effect on intestinal α-glucosidase, but not on pancreatic α-amylase. Soy isoflavones also decreased glucose transport potency into brush border membrane vesicles or Caco-2 cells. It is concluded that soy isoflavones from hypocotyl, performs hypoglycemic function in GK rats with type 2 diabetes, maybe via suppression of carbohydrate digestion and glucose uptake in small intestine.

[Rhaponticum uniflorum inhibits H2O2-induced apoptosis of liver cells via JNK and NF-κB pathways].

To study the inhibitory effect of Rhaponticum uniflorum on apoptosis induced by H2O2 in HepG2 cells. Human HepG2 cells injury models were established by H2O2, then cell survival rate was assayed by MTT method; levels of LDH, ALT, and AST were detected by chemical colorimetric method;SOD activity was detected by xanthine oxidase method; GSH content was detected by dithio-bis-nitrobenzoic acid(DTNB); MDA level was detected by thiobarbituric acid (TBA) method;and the relative activities of Caspase-3, 8 and 9 were measured by Colorimetry. The expression levels of Cleaved Caspase-3(Casp-3), cytochrome(Cyto c), NF-κB, ERK, JNK, p38 MAPK, as well as the phospharylated proteins were determined with Western blotting method. The results showed that R. unifloru had no significant effect on cell viabilities of HepG2 cells at the concentrations of 25-400 mg•L⁻¹. However, H2O2decreased the cell viabilities, increased the cellular oxidative stress, and up-regulated the protein expressions of Casp-3, cytoplasmic Cyto c, p-JNK and nuclear NF-κB. As compared with the model group,R. unifloru could increase the cell viability, reduce LDH, ALT and AST leakage, reduce the MDA formation, increase the SOD and GSH levels,reduce the relative activities of Caspase-3, 8 and 9, down-regulated the protein expressions of Casp-3 and cytoplasmic Cyto c, and down-regulate the p-JNK and nuclear NF-κB levels.The results indicated that R. unifloru had the inhibitory effect on apoptosis induced by H2O2in HepG2 cells, and the mechanism maybe associated with inhibiting JNK activation and NF-κB nuclear translocation.

Suppression of p53-inducible gene 3 is significant for glioblastoma progression and predicts poor patient prognosis.

Glioblastoma is the most malignant and invasive brain tumor with extremely poor prognosis. p53-inducible gene 3, a downstream molecule of the tumor suppressor p53, has been found involved in apoptosis and oxidative stress response. However, the functions of p53-inducible gene 3(PIG3) in cancer are far from clear including glioblastoma. In this study, we found that p53-inducible gene 3 expression was suppressed in glioblastoma tissues compared with normal tissues. And the expression of p53-inducible gene 3 was significantly associated with the World Health Organization grade. Patients with high p53-inducible gene 3 expression have a significantly longer median survival time (15 months) than those with low p53-inducible gene 3 expression (8 months). According to Cox regression analysis, p53-inducible gene 3 was an independent prognostic factor with multivariate hazard ratio of 0.578 (95% confidence interval, 0.352-0.947; p = 0.030) for overall survival. Additionally, gain and loss of function experiments showed that knockdown of p53-inducible gene 3 significantly increased the proliferation and invasion ability of glioblastoma cells while overexpression of p53-inducible gene 3 inhibited the proliferation and invasion ability. The results of in vivo glioblastoma models further confirmed that p53-inducible gene 3 suppression promoted glioblastoma progression. Altogether, our data suggest that high expression of p53-inducible gene 3 is significant for glioblastoma inhibition and p53-inducible gene 3 independently indicates good prognosis in patients, which might be a novel prognostic biomarker or potential therapeutic target in glioblastoma.

Docetaxel-loaded PEG-albumin nanoparticles with improved antitumor efficiency against non-small cell lung cancer.

The aim of the present study was mainly to assess the advantage of docetaxel-loaded PEG-albumin nanoparticles (PEG-DANPs) against non-small cell lung cancer (NSCLC) compared with the commercial product of docetaxel (Aisu®) and docetaxel-albumin nanoparticles (DANPs). We made systematic assessments on these three drugs against NSCLC both in vitro and in vivo. Based on our experiments, PEG-DANPs showed a dose- and time-dependent efficacy in the in vitro cytotoxicity studies; the tumors growth and the metastases in the livers of NSCLC-bearing nude mice in vivo were reduced dmarkedly by PEG-DANPs, and the PEG-DANP-treated mice had a minimum of weight loss; furthermore, the mice which were treated with PEG-DANPs can survive longer than the other groups. In conclusion, the PEG-DANPs have the lowest side-effects, and the highest antitumor and metastases activity of the three drugs, and it may provide an alternative to patients with NSCLC.

A comparative study on the effect of docetaxel-albumin nanoparticles and docetaxel-loaded PEG-albumin nanoparticles against non-small cell lung cancer.

The present study mainly compared the effect of docetaxel-albumin nanoparticles (DANPs) and docetaxel-loaded PEG-albumin nanoparticles (PEG-DANPs) against non-small cell lung cancer (NSCLC). We made systematic assessments on these three drugs against NSCLC both in vitro and in vivo. With the purpose of eliminating side-effects of the commercial formulation (Tween-80) and prolonging the blood circulation time, we used emulsion-evaporation cross-link method to prepare DANPs and PEG-DANPs. The DANPs had an average particle size of 163.4 ± 3.76 nm, a zeta potential of -19.4 ± 0.18 mV, a polydispersity index of 0.143 ± 0.03, a drug loading of 8.71 ± 0.98%, and an encapsulation efficiency of 93.58 ± 0.86%; the average particle size of PEG-DANPs is 169.19 ± 2.36 nm, zeta potential is -18.2 ± 0.21 mV, with a polydispersity index of 1.56 ± 0.05, a drug loading of 8.72 ± 1.05% and an encapsulation efficiency of 95.4 ± 5.5%. PEG-DANPs showed a dose- and time-dependent efficacy in cytotoxicity studies in vitro; the hemolysis test indicated that PEG-DANPs had less hemocytolysis than Aisu® and DANPs; in addition, a more prolonged circulation time and sustained in vitro release behavior were observed in the PEG-DANPs compared with Aisu® and DANPs; the cellular uptake test in vitro demonstrated that PEG-DANPs could be absorbed easier into the nucleus; furthermore, the tumor growth of NSCLC-bearing nude mice in vivo was reduced the most by PEG-DANPs. In conclusion, the PEG-DANPs have the lowest side-effects, the highest antitumor activity with the longest blood circulation time of the three drugs, and it will provide an alternative to patients with NSCLC.

Evaluation of doxorubicin-loaded pH-sensitive polymeric micelle release from tumor blood vessels and anticancer efficacy using a dorsal skin-fold window chamber model.

AIM: To evaluation the doxorubicin (DOX)-loaded pH-sensitive polymeric micelle release from tumor blood vessels into tumor interstitium using an animal vessel visibility model, the so-called dorsal skin-fold window chamber model. METHODS: DOX-loaded pH-sensitive polyHis-b-PEG micelles and DOX-loaded pH-insensitive PLLA-b-PEG micelles were prepared. The uptake of the micelles by MDA-MB-231 breast cancer cells in vitro and in vivo was examined using flow cytometry. The pharmacokinetic parameters of the micelles were determined in SD rats after intravenous injection of a DOX dose (6 mg/kg). The release of the micelles from tumor vasculature and the antitumor efficacy were evaluated in MDA-MB-231 breast cancer xenografted in nude mice using a dorsal skin-fold window chamber. RESULTS: The effective elimination half-life t1/2 of the pH-sensitive, pH-insensitive polymeric micelles and DOX-PBS in rats were 11.3 h, 9.4 h, and 2.1 h, respectively. Intravital microscopy in MDA-MB-231 breast cancer xenografted in nude mice showed that the pH-sensitive polymeric micelles rapidly extravasated from the tumor blood vessels, and DOX carried by the pH-sensitive micelles was preferentially released at the tumor site as compared to the pH-insensitive polymeric micelles. Furthermore, the pH-sensitive polymeric micelles exhibited significant greater efficacy in inhibition of tumor growth in the nude mice. CONCLUSION: When DOX is loaded into pH-sensitive polymeric micelles, the acidity in tumor interstitium causes the destabilization of the micelles and triggers drug release, resulting in high local concentrations within the tumor, thus more effectively inhibiting the tumor growth in vivo.

BRP, a polysaccharide fraction isolated from Boschniakia rossica, protects against galactosamine and lipopolysaccharide induced hepatic failure in mice.

The aim of this study was to investigate the hepatoprotective effect of BRP, a polysaccharide fraction isolated from Boschniakia rossica, against galactosamine and lipopolysaccharide induced fulminant hepatic failure. Mice were injected with a single dose of galactosamine/lipopolysaccharide with or without pretreatment of BRP. Results showed marked reduction of hepatic necrosis, serum marker enzymes and levels of tumor necrosis factor-α and interleukin-6 in BRP pretreated mice when compared with galactosamine/lipopolysaccharide-challenged mice. Mice pretreated with BRP decreased the activation of caspases-3 and caspase-8, and showed a reduced level of DNA fragmentation of liver cells. BRP also reduced hepatic lipid peroxidation, increased potential of hepatic antioxidative defense system, and reduced hepatic nitric oxide level which was elevated by galactosamine/lipopolysaccharide injection. Immunoblot analysis showed down-regulation of inducible nitric oxide synthase and cyclooxygenase-2 proteins of liver tissues in BRP pretreated group when compared with galactosamine/lipopolysaccharide-challenged group. Furthermore, treatment with galactosamine/lipopolysaccharide markedly increased toll-like receptor 4, nuclear level of nuclear factor-κB, and phosphorylation of both extracellular signal-regulated kinase and c-Jun N-terminal kinase in liver tissues. However, these increases were attenuated by pretreatment with BRP. The results suggest that BRP alleviates galactosamine/lipopolysaccharide-induced liver injury by enhancing antioxidative defense system, suppressing inflammatory responses and reducing apoptotic signaling.

Improved anti-tumor efficiency against prostate cancer by docetaxel-loaded PEG-PCL micelles.

This study primarily focused on the systematic assessment of both in vitro and in vivo anti-tumor effects of docetaxel-loaded polyethylene glycol (PEG)2000-polycaprolactone (PCL)2600 micelles on hormone-refractory prostate cancer (HRPC). By using solvent evaporation method, PEG-PCL was chosen to prepare doxetaxel (DTX)-loaded mPEG-PCL micelles (DTX-PMs), with the purpose of eliminating side effects of the commercial formulation (Tween 80) and prolonging the blood circulation time. The prepared DTX-PMs had an average particle size of 25.19±2.36 nm, a zeta potential of 0.64±0.15 mV, a polydispersity index of 0.56±0.03, a drug loading of (8.72±1.05)%, and an encapsulation efficiency of (98.1±8.4)%. In vitro cytotoxicity studies indicated that DTX-PMs could effectively kill LNCap-C4-2B cells and show a dose- and time-dependent efficacy. The hemolysis test showed that DTX-PMs had less hemocytolysis than the commercial product of Duopafei®. A sustained in vitro release behavior and prolonged circulation time in blood vessels were observed in the DTX-PMs. Furthermore, when compared with Duopafei®, the DTX-PMs dramatically reduced the prostate specific antigen (PSA) level and tumor growth of prostate tumor-bearing nude mice in vivo. In conclusion, the DTX-PMs can lower systemic side effects, improve anti-tumor activity with prolonged blood circulation time, and will bring an alternative to patients with HRPC.

[Protective effect of soyasaponins on acute liver injury induced by D-galactosamine and lipopolysaccharide in mice].

OBJECTIVE: To investigate the protective effect of soyasaponins on acute liver injury induced by D-galactosamine (GalN) and lipopolysaccharide (LPS) in mice. METHOD: The mice were randomly divided into five groups: the normal control, the model group, the silymarin (positive control) group, and soyasaponins high and low-dose groups. They were administered with drugs once every day for 7 days. At the end of the experiment, GalN and LPS were injected intraperitoneally to all of the groups except for the normal group to establish the acute liver injury model. The pathological changes were detected with hematoxylin & eosin (HE) staining, tumor necrosis factor-alpha (TNF-alpha) was detected by ELISA method, and the alanine aminotransferase (ALT), aspartate aminotransferase (AST), catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), and the activation of Caspase-3 and Caspase-8 were detected by the colorimetric method. RESULT: Soyasaponins could reduce the activities of serum ALT and AST, the acute hepatic injury induced by GalN/LPS, serum TNF-alpha level, hepatic NO and MDA contents, and the Caspase-3 and Caspase-8 activations of liver tissues, and increase the hepatic CAT, GPx, GST and GSH levels. CONCLUSION: Soyasaponins shows the protective effect on acute liver injury induced by GalN and LPS in mice, which may be related to its antioxidative ability and anti-liver apoptosis.

Hepatoprotective effect of polysaccharides from Boschniakia rossica on carbon tetrachloride-induced toxicity in mice.

The purpose of this study was to investigate the protective effect of polysaccharides from Boschniakia rossica against hepatotoxicity induced by carbon tetrachloride (CCl4). Boschniakia rossica polysaccharides was administered intragastrically once daily for 7 days. One hour after the final treatment, mice were treated intraperitoneally with 80 mg/kg of CCl4. CCl4-induced hepatotoxicity was manifested by increased levels of serum marker enzymes and hepatic lipid peroxidation, and by decreased potential of hepatic antioxidative defense system. CCl4 challenge also resulted in elevated serum tumor necrosis factor-α and hepatic nitric oxide level, and up-regulation of inducible nitric oxide synthase and cyclooxygenase-2 proteins of liver tissue. Pretreatment of mice with Boschniakia rossica polysaccharides reversed these altered parameters of mice with liver injury induced by CCl4. Furthermore, caspase-3 cleavage and activities, and DNA fragmentation of liver in mice treated with Boschniakia rossica polysaccharides were decreased than mice treated with CCl4 alone. Hepatoprotective effect of Boschniakia rossica polysaccharides was further demonstrated by histopathological examination of liver sections. The results indicate that Boschniakia rossica polysaccharides play a protective role in CCl4-induced acute liver injury and the hepatoprotective effect of Boschniakia rossica polysaccharides may be due to elevated antioxidative defense potentials, suppressed inflammatory responses and apoptosis of liver tissue.

Preparation and characterization of polymeric nanoparticles for siRNA delivery to down-regulate the expressions of exogenous and endogenous target genes.

Gene silencing induced by RNA interference using small interfering RNA (siRNA) provides a promising therapeutic approach for cancers. However, the lack of siRNA delivery vector has limited the development of siRNA therapy. The purpose of this study was to use the novel copolymer (mPEG5k-PCL1.2k)1.4-g-PEl10k to prepare siRNA-loaded nanoparticles for siRNA delivery. The results suggested that (mPEG5k-PCL1.2k)1.4-g-PEl10k could load siRNA to form nanoparticles with particle size less than 200 nm in a narrow distribution. Moreover, a certain density of positive charge existed onto the surfaces of nanoparticles. MTT assay results demonstrated that (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles showed very low cytotoxicity. The gene silencing efficiency of (mPEG5k-PCL1.2k)1.4-g-PEl10k/siRNA nanoparticles was investigated through luciferase reporter gene assays. The expression of exogenous luciferase gene was significantly downregulated at a range of N/P ratio from 50 to 125, and was maximally inhibited at the N/P ratio of 125 with 54% and 59% reduction in MCF-7 and HepG2 cells, respectively. In the 4T1-luc cell line expressing luciferase stably, the silencing of endogenous luciferase gene also has a similar overall profile with maximal 54% reduction of luciferase expression. These results suggested that (mPEG5k-PCL1.2k)1.4-g-PEI10k/SiRNA nanoparticles could serve as a kind of highly efficient siRNA delivery system for down-regulating the expression of exogenous and endogenous target genes.

Boschniakia rossica prevents the carbon tetrachloride-induced hepatotoxicity in rat.

The present study was undertaken to investigate the hepatoprotective effect of Boschniakia rossica extract (BRE), rich in phenylpropanoid glycoside and iridoid glucoside, on CCl(4)-induced liver damage. Male Wistar rats were randomly divided into six groups of ten each. While the first group was maintained as normal control, groups II-VI were administered 0.5 ml/kg CCl(4) (model), 100mg/kg BRE plus CCl(4), 200mg/kg BRE plus CCl(4), 50mg/kg silymarin plus CCl(4) and 200mg/kg BRE, respectively. CCl(4) challenge not only elevated the serum marker enzyme activities and reduced albumin (ALB) level but also increased liver oxidative stress, as evidenced by elevated lipid hydroperoxide (LOOH) and malondialdehyde (MDA) concentrations, combined with suppressed potential of hepatic antioxidative defense system including superoxide dismutase (SOD), glutathione peroxidase (GPx) activities and reduced glutathione (GSH) content. Furthermore, serum tumor necrosis factor-α (TNF-α), hepatic nitrite level, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein contents were elevated while cytochrome P450 2E1 (CYP2E1) expression and function were inhibited. Preadministration of BRE not only reversed the significant changes in serum toxicity markers, hepatic oxidative stress, xenobiotic metabolizing enzymes and proinflammatory mediators induced by CCl(4) but also restored liver CYP2E1 level and function. Interestingly, the protein expression of heme oxygenase-1 (HO-1) was further elevated by BRE treatment, which was markedly increased after CCl(4) challenge. These results demonstrate that BRE exhibits protective effect on CCl(4)-induced acute hepatic injury via, at least in part, reduced oxidative stress, suppressed inflammatory responses and induced HO-1 protein expression combined with improved CYP2E1 level and function in liver.

Multifunctional nanoparticles for targeting cancer therapy.

Chemotherapy drug Doxorubicin and MRI imaging agent Iron Oxide were encapsulated in dual functional nanoparticles which is compose of PEG-Foliate acid polymers. The particle size was about 45 nm with a mono-dispersion measured by zeta-sizer instrument. The contrast of images in liver was enhanced after injection Nanoparticles via rabbit ear vein. PEG-FA coated Iron Oxide nanoparticles can selectively target to tumor site and effectively inhibit tumor growth which is subcutaneously bearing A2780 Overran cancer cells. It is feasible for cancer treatment with MRI imaging and chemotherapy simultaneously in vivo by injection dual functional nanoparticles.

Rossicaside B protects against carbon tetrachloride-induced hepatotoxicity in mice.

The protective effect of rossicaside B, the major phenylpropanoid glycoside from Boschniakia rossica, on CCl(4)-induced hepatotoxicity and the mechanisms underlying its protective effect were investigated. The mice were administered orally with rossicaside B (100 or 200 mg/kg of body weight) 48, 24 and 1 hr before CCl(4) (0.5 ml/kg of body weight) administration. The CCl(4) challenge caused a marked increase in the levels of serum aspartate aminotransferase, alanine aminotransferase and of tumour necrosis factor-alpha, and propagated lipid peroxidation with a concomitant reduction in reduced glutathione (GSH) and antioxidative enzyme activities in the liver. The administration of rossicaside B to CCl(4)-treated mice not only decreased the serum toxicity marker enzymes and TNF-alpha but also reduced hepatic oxidative stress, as demonstrated by decreased lipid hydroperoxide and thiobarbituric acid-reactive substance concentrations, combined with elevated GSH content and antioxidative enzyme activities in the liver tissues. Furthermore, the contents of hepatic nitrite, inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and haem oxygenase-1 (HO-1) were elevated after CCl(4) treatment while the cytochrome P450 2E1 (CYP2E1)-specific monooxygenase activity was suppressed. Rossicaside B treatment inhibited the formation of liver nitrite, reduced the over-expression of iNOS and COX-2 proteins, but increased the CYP2E1 function compared with the CCl(4)-treated mice. However, the protein expression of HO-1 was further elevated by rossicaside B treatment. The results demonstrate that rossicaside B provides a protective action on CCl(4)-induced acute hepatic injury, which may be related to its antioxidative activity, suppressed inflammatory responses, induced HO-1 expression and improved CYP2E1 function in the liver.

Protective effect of iridoid glucosides from Boschniakia rossica on acute liver injury induced by carbon tetrachloride in rats.

The protective effect of iridoid glucosides from Boschniakia rossica (BRI) against carbon tetrachloride (CCl4)-induced liver injury was examined. CCl4 at a dose of 0.5 ml/kg of body weight was given intraperitoneally to rats to induce liver damage. The rats were sacrificed 16 h after the CCl4 injection. The CCl4 challenge caused a marked increase in the levels of serum animotransferases, tumor necrosis factor-alpha (TNF-alpha) and of hepatic inducible nitric oxide synthase (iNOS) protein, depleted reduced glutathione (GSH), and propagated lipid peroxidation. The liver antioxidative defense system, including superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR), as well as the cytochrome P450 2E1 (CYP2E1) expression were suppressed, however. Preadministration of BRI reversed the significant changes of all liver function parameters induced by CCl4 and restored the liver CYP2E1 content and function. These results demonstrate that BRI produced a protective action on CCl4-induced acute hepatic injury via reduced oxidative stress, suppressed inflammatory response and improved CYP2E1 function in the liver.

Dendroaspis natriuretic peptide relaxes gastric antral circular smooth muscle of guinea-pig through the cGMP/cGMP-dependent protein kinase pathway.

AIM: To systematically investigate if cGMP/cGMP-dependent protein kinase G (PKG) signaling pathway may participate in dendroaspis natriuretic peptide (DNP)-induced relaxation of gastric circular smooth muscle. METHODS: The content of cGMP in guinea pig gastric antral smooth muscle tissue and perfusion solution were measured using radioimmunoassay; spontaneous contraction of gastric antral circular muscles recorded using a 4-channel physiograph; and Ca(2+)-activated K(+) currents (I(K(Ca))) and spontaneous transient outward currents (STOCs) in isolated gastric antral myocytes were recorded using the whole-cell patch clamp technique. RESULTS: DNP markedly enhanced cGMP levels in gastric antral smooth muscle tissue and in the perfusion medium. DNP induced relaxation in gastric antral circular smooth muscle, which was inhibited by KT5823, a cGMP-dependent PKG inhibitor. DNP increased I(K(Ca)). This effect was almost completely blocked by KT5823, and partially blocked by LY83583, an inhibitor of guanylate cyclase to change the production of cGMP. DNP also increased STOCs. The effect of DNP on STOCs was abolished in the presence of KT5823, but not affected by KT-5720, a PKA-specific inhibitor. CONCLUSION: DNP activates I(K(Ca)) and relaxes guinea-pig gastric antral circular smooth muscle via the cGMP/PKG-dependent singling axis instead of cAMP/PKA pathway.