A novel and simple hollow-fiber assay for in vivo evaluation of nonpeptidyl thrombopoietin receptor agonists.

Preclinical in vivo assessment of the pharmacologic activity of nonpeptidyl thrombopoietin receptor (TPOR) agonists is very difficult because of the high species specificity of such agonists. In this study, we have developed a novel and simple in vivo hollow-fiber assay to preclinically evaluate TPOR agonists. The 32D-mpl cell line was generated by stable transfection of human TPOR into 32D lymphoblast cells and shown to be a specific model for nonpeptide TPOR agonists in vitro. Stably transfected 32D-mpl cells were then sealed in hollow fibers and implanted into nude mice. Cells in hollow fibers specifically responded to TPOR agonists, including thrombopoietin and eltrombopag, a nonpeptide small-molecule TPOR agonist, but not to granulocyte colony-stimulating factor or erythropoietin. Oral administration of eltrombopag stimulated 32D-mpl cell proliferation, prevented 32D-mpl cell apoptosis, and stimulated the phosphorylation of cellular signaling transducers and activators of transcription in a TPOR- and dose-dependent manner. These results indicate that the hollow-fiber assay is a specific and efficient model for rapidly evaluating the in vivo activity of small-molecule TPOR agonists.

Protective effects of aucubin on H2O2-induced apoptosis in PC12 cells.

The present study investigated the neuroprotective effects of aucubin on hydrogen peroxide (H2O2)-induced apoptosis in PC12 cells. Exposure of PC12 cells to 0.25 mm H2O2 induced a leakage of lactate dehydrogenase and decreased cell viability, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In a dose over 0.1 mm, aucubin increased PC12 cellular viability and markedly attenuated H2O2-induced apoptotic cell death. Quantitation of apoptosis by flow cytometry indicated that aucubin inhibited H2O2-induced apoptosis in PC12 cells. Nuclear damage was alleviated by aucubin, as shown by Hoechst staining. In addition, the levels of malondialdehyde were reduced and the activity of superoxide dismutase, catalase and glutathione peroxidase was augmented in these cells. These results indicated that aucubin inhibited H2O2-induced apoptosis in PC12 cells through regulation of the endogenous oxidant-antioxidant balance. Our results suggest that aucubin is a potential protective agent for the treatment of oxidative-stress-induced neurodegenerative disease.

Aucubin prevents loss of hippocampal neurons and regulates antioxidative activity in diabetic encephalopathy rats.

In this study, the neuroprotection of aucubin and its mechanism were evaluated in the rat model of diabetic encephalopathy. Diabetes mellitus (DM) rats were stratified by cognitive capability (CC), and assigned to four treatment groups for aucubin treatment (doses of 0, 1, 5 or 10 mg/kg aucubin), with a further two groups of non-DM rats ranked by CC as controls for aucubin (doses of 0 or 5 mg/kg aucubin). Neuroprotection was estimated by the indexes of behavior and histology. Behavioral testing was performed in a Y-maze. The surviving neurons in CA1-CA4 and subiculum (SC) of the hippocampus were counted under a microscope. In addition, the apoptotic neurons in the CA1 of the hippocampus were also examined by using TUNEL staining. In order to clarify the mechanism of aucubin's neuroprotection, the activities of endogenous antioxidants and nitric oxide synthase (NOS) together with the content of lipid peroxide in the hippocampus were assayed. The results proved that aucubin significantly reduced the content of lipid peroxide, regulated the activities of antioxidant enzymatic and decreased the activity of NOS. All these effects indicated that aucubin was a potential neuroprotective agent and its neuroprotective effects were achieved, at least in part, by promoting endogenous antioxidant enzymatic activities.

Protective effect of Acanthopanax senticosus extract against endotoxic shock in mice.

AIM OF THE STUDY: In this study, we evaluated protective effect of Acanthopanax senticosus extract (ASE) and a possible signaling pathway involved during endotoxic shock induced by intraperitoneal injection lipopolysaccharide (LPS) and D-galactosamine (D-GalN) in BALB/c mice. MATERIALS AND METHODS: Mice were intraperitoneal administrated with ASE (100, 200 or 400mg/kg) prior to injection of 50 microg/kg LPS and 1g/kg D-GalN. The levels of tumor necrosis-alpha (TNF-alpha) and interleukin-10 (IL-10) in serum and liver. Nitric oxide (NO) production in serum and inducible nitric oxide synthase (iNOS) protein level were investigated. Nuclear factor-kappa B (NF-kappaB) activation in liver was determined. Furthermore, we evaluated the effect of ASE pretreatment on infiltration of inflammatory cells into the heart, liver and lung of mice. RESULTS: Treatment of mice with ASE prior to LPS/D-GalN injection significantly improved the survival rate. ASE pretreatment inhibited the elevation of TNF-alpha in serum and liver. ASE also decreased iNOS level in liver and the overproduction of nitric oxide (NO) in serum. In addition, IL-10 levels in serum and liver were markedly enhanced. ASE pretreatment inhibited NF-kappaB activation in liver of mice. Moreover, infiltration of inflammatory cells into the heart, liver and lung of mice was also attenuated by ASE pretreatment. CONCLUSIONS: These results suggested that ASE protected mice against LPS/D-GalN-induced endotoxic shock involving inhibition of NF-kappaB activation, which caused down-regulation of TNF-alpha and involved up-regulation of IL-10. Acanthopanax senticosus may thus prove beneficial in the prevention of endotoxic shock.

Acanthopanax senticosus suppresses reactive oxygen species production by mouse peritoneal macrophages in vitro and in vivo.

Excess production of reactive oxygen species by macrophages has been implicated in many inflammatory diseases. The present study investigated the inhibitory effect of the stem bark extract of Acanthopanax senticosus on the production of superoxide anion and hydrogen peroxide in mouse peritoneal macrophages in vitro and in vivo. Exposure of mouse peritoneal macrophages to A. senticosus extract significantly suppressed superoxide anion production induced by zymosan in a dose-dependent manner. Similarly, exposure of mouse peritoneal macrophages to A. senticosus extract significantly inhibited hydrogen peroxide production induced by phorbol 12-myristate 13-acetate (PMA) in a dose-dependent manner. Intraperitoneal administration of A. senticosus extract to KM mice reduced the ex vivo production of zymosan induced-superoxide anion and PMA-induced hydrogen peroxide by their peritoneal macrophages. Exposure to A. senticosus extract did not affect the cell viability or systemic toxicity. A. senticosus inhibited reactive oxygen species production by mouse peritoneal macrophages in vitro and in vivo and may be partly responsible for the antiinflammatory function.

Inhibition of inducible nitric oxide synthase by Acanthopanax senticosus extract in RAW264.7 macrophages.

AIM OF THE STUDY: The herb Acanthopanax senticosus (Siberian ginseng) has long been used as a traditional medicine. However, little is known about anti-inflammatory effects and its mechanisms of action. Excess production of nitric oxide (NO) is one of the characteristics of inflammation. In this study we examined the effects of A. senticosus extract (ASE) on NO production and inducible nitric oxide synthase (iNOS) gene expression in lipopolysaccharide (LPS) plus interferon-gamma (IFN-gamma)-stimulated RAW264.7 macrophages and investigated its mechanisms of anti-inflammatory activity. MATERIALS AND METHODS: RAW264.7 macrophages were treated with 10 microg/ml LPS plus 20U/ml IFN-gamma in the presence or absence of ASE. NO production and iNOS gene expression were investigated. We further evaluated the effect of ASE on oxidative stress-sensitive transcription nuclear factor-kappa B (NF-kappaB) activation. RESULTS: ASE significantly suppressed NO production and iNOS gene expression in a dose-dependent manner. ASE also reduced DNA-binding activity of NF-kappaB in LPS plus IFN-gamma stimulated RAW264.7 macrophages. Further studies indicated that LPS plus IFN-gamma-induced inhibitory factor-kappa B alpha (I-kappaBalpha) degradation and p65 nuclear translocation were inhibited in RAW264.7 macrophages exposed to ASE. Moreover, ASE inhibited the LPS plus IFN-gamma mediated increase in intracellular peroxides production. CONCLUSIONS: These results suggest ASE suppresses iNOS gene expression through the inhibition of intracellular peroxides production, which has been implicated in the activation of NF-kappaB.

Acanthopanax senticosus inhibits nitric oxide production in murine macrophages in vitro and in vivo.

Excess nitric oxide (NO) production has been implicated in inflammatory diseases. The present study investigated the inhibitory effect of the stem bark extract of Acanthopanax senticosus (A. senticosus) on NO production in murine macrophages in vitro and in vivo. In vitro exposure of RAW264.7 cells to 1, 10, 50, 100, 250, 500 and 1000 microg/mL of A. senticosus extract significantly suppressed NO production induced by lipopolysaccharide (LPS) and interferon gamma (IFN-gamma) in a dose-dependent manner. In vitro exposure of mouse resident peritoneal macrophages to 1, 10, 100 and 1000 microg/mL of A. senticosus extract significantly suppressed NO production induced by LPS and IFN-gamma in a dose-dependent manner. In vivo administration of A. senticosus extract (50, 100 and 200 mg/kg) to KM mice dose-dependently inhibited LPS and IFN-gamma induced production of NO in isolated mouse peritoneal macrophages ex vivo. Exposure to A. senticosus extract had no effect on cell viability and systemic toxicity. The results demonstrated that the stem bark extract of A. senticosus extract inhibits NO production in murine macrophages in vitro and in vivo.