OBJECTIVEThis study aimed to investigate the roles of platelet activating factor (PAF) receptor antagonist in damage to intestinal mucin-2 (MUC2) during endotoxemia on young rats.

METHODSEighteen-day-old Wistar rats were randomized to be treated with lipopolysaccharide (LPS) (5 mg/kg), LPS plus PAF receptor antagonist and normal saline injection (control). PAF receptor antagonist BN52021 5 mg/kg was administered 30 minutes before or after LPS injection (pretreatment group or treatment group). The ileum specimens (n = 8) were harvested at 1.5, 3, 6, 24, 48 and 72 hours after LPS injection. Transmission electron microscopy was used for morphologic evaluation. Immunohistochemistry was used to determine MUC2 in intestinal mucosa.

RESULTSMicrovilli and tight junctions were intact in the control group. Enlargement of tight junctions were seen in the LPS group and microvilli were thin, rare or disrupted, shed. The rough endoplasmic reticulum, mitochondria, and glycogen particles were injured. The changes of the pretreatment and treatment group were slightly milder than that in the LPS group. Ileum of a control rat in which a thin layer of mucus covering the epithelial surface and mucin-containing goblet cells appeared very distended. The experiment group showed a decrease or irregularly distributed membranous mucus expression. The MUC2 content of absorbance significantly decreased in the LPS challenged group compared with that in the control group (P < 0.01), and reached a nadir at 6 hours (0.1841 +/- 0.0047) vs. the control group (0.2091 +/- 0.0060) (P < 0.01). The tendency of the level of MUC2 in the pretreatment and treatment group was the same as that of the LPS group, and the level of MUC2 in the pretreatment and treatment group was higher than that in the LPS group at each time point. ANOVA analysis showed that the inter-group and intra-group difference had statistical significance (P < 0.05).

CONCLUSIONSPAF may play some roles in the injury of intestinal mucus barrier function during endotoxemia. Preventive and remedial use of PAF receptor antagonist BN52021 may relieve intestinal injury.

Animals ; Endotoxemia ; metabolism ; pathology ; Intestinal Mucosa ; drug effects ; metabolism ; pathology ; Mucin-2 ; metabolism ; Platelet Membrane Glycoproteins ; antagonists & inhibitors ; Rats ; Rats, Wistar ; Receptors, G-Protein-Coupled ; antagonists & inhibitors

Alzheimer Disease ; drug therapy ; enzymology ; Amyloid Precursor Protein Secretases ; antagonists & inhibitors ; Animals ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Humans ; Medicine, Chinese Traditional ; methods ; Membrane Glycoproteins ; antagonists & inhibitors ; Molecular Targeted Therapy ; Phytotherapy ; methods ; Presenilins ; antagonists & inhibitors

The second nonligand binding chain of IL-6 receptor (IL-6R), the membrane glycoprotein with 130 kD mol wt (gp130), is responsible for the signal transduction of IL-6 biological activity. Our experiments indicated that the rat gp130 molecule, which was expressed in the rat acute myeloid leukemia cell line R2, could associate with the complex of rhIL-6 and membrane human IL-6R molecule and transduce the inhibition-inducing signal on R2 cells. In the present study, antisense oligonucleotides of rat gp130 were synthesized and uptaked into the R2 cells. Then the effects of the antisense or sense nucleic acids of rat gp130 on the inhibition induced by rhIL-6 in the R2 cell were investigated. Our results show that the antisense oligonucleotide of rat gp130 blocked the inhibitory effect of rhIL-6 on the R2 cells by (45 +/- 7)% at the optimal concentration
Acute Disease ; Animals ; Antigens, CD ; genetics ; Cell Division ; drug effects ; Cytokine Receptor gp130 ; Drug Interactions ; Interleukin-6 ; antagonists & inhibitors ; pharmacology ; Leukemia, Myeloid ; pathology ; Membrane Glycoproteins ; antagonists & inhibitors ; genetics ; Oligonucleotides, Antisense ; chemical synthesis ; chemistry ; pharmacology ; Rats ; Tumor Cells, Cultured

OBJECTIVETo observe the platelet activating factor (PAF) antagonistic effect of kaempferol.

METHODThe specific binding of [3H] PAF to rabbit platelet receptor was investigatedwith radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was determined with Fura-2 fluorescent technique.

RESULTThe 1, 2 or 4 nmol x L(-1) [3H]PAF specific binding to rabbit platelet receptor was inhibited by Kae dosage dependently and the IC50 were 30.8, 74.6 and 92.0 micro mol x L(-1), respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration elevation were inhibited by Kae in a dose-dependent manner. The IC50 of Kae to inhibit platelet adhesion was 65 micromol x L(-1).

CONCLUSIONKae is effective in inhibiting the action of PAF and it is a new PAF receptor antagonist.

Animals ; Blood Platelets ; drug effects ; physiology ; Calcium ; metabolism ; Kaempferols ; pharmacology ; Male ; Neutrophils ; metabolism ; Platelet Activating Factor ; metabolism ; Platelet Adhesiveness ; drug effects ; Platelet Membrane Glycoproteins ; antagonists & inhibitors ; metabolism ; Rabbits ; Radioligand Assay ; Receptors, G-Protein-Coupled ; antagonists & inhibitors ; metabolism

Xanthohumol (XH), the principal prenylflavonoid of the hop plant (Humulus lupulus L.), dose-dependently inhibited isobutylmethylxanthine (IBMX)-induced melanogenesis in B16 melanoma cells, with little cytotoxicity at the effective concentrations. Decreased melanin content was accompanied by reduced tyrosinase enzyme activity, protein and mRNA expression. The levels of tyrosinase-related protein 1 and 2 mRNAs were decreased by XH. XH also inhibited alpha-melanocyte stimulating hormone- or forskolin-induced increases in melanogenesis, suggesting an action on the cAMP-dependent melanogenic pathway. XH downregulated the protein and mRNA expression of microphthalmia-associated transcription factor (MITF), a master transcriptional regulator of key melanogenic enzymes. These results suggest that XH might act as a hypo-pigmenting agent through the downregulation of MITF in the cAMP-dependent melanogenic pathway.
1-Methyl-3-isobutylxanthine/pharmacology ; Animals ; Cell Line ; Cell Survival/drug effects ; Dose-Response Relationship, Drug ; Down-Regulation ; Drug Antagonism ; Forskolin/pharmacology ; *Humulus ; Intramolecular Oxidoreductases/antagonists & inhibitors/biosynthesis ; Melanins/antagonists & inhibitors/*biosynthesis ; Melanocytes/*drug effects/*metabolism ; Melanoma, Experimental ; Membrane Glycoproteins/antagonists & inhibitors/biosynthesis ; Mice ; Microphthalmia-Associated Transcription Factor/antagonists & inhibitors ; Monophenol Monooxygenase/antagonists & inhibitors/biosynthesis/genetics ; Oxidoreductases/antagonists & inhibitors/biosynthesis ; Propiophenones/*pharmacology ; Signal Transduction/drug effects ; alpha-MSH/metabolism

TNF-related apoptosis-inducing ligand (TRAIL/Apo- 2L), a newly identified member of the TNF family promotes apoptosis by binding to the transmembrane receptors (TRAIL-R1/DR4 and TRAIL-R2/ DR5). TRAIL known to activate NF-kappa B in number of tumor cells including A549 (wt p53) and NCI- H1299 (null p53) lung cancer cells exerts relatively selective cytotoxic affects to the human tumor cell lines without much effect on the normal cells. We set out to identify an agent that would sensitize lung cancer cells to TRAIL-induced apoptosis through inhibition of NF-kappa B activation. We found that triptolide, an oxygenated diterpene extracted and purified from the Chinese herb Tripterygium wilfordii sensitized A549 and NCI-H1299 cells to TRAIL-induced apoptosis through inhibition of NF-kappa B activation. Pretreatment with MG132 which is a well-known NF-kappa B inhibitor by blocking degradation of Ikappa B alpha also greatly sensitized lung cancer cells to TRAIL-induced apoptosis. Triptolide did not block DNA binding of NF-kappa B activated by TRAIL as in the case of TNF-alpha. It has been already proven that triptolide blocks transactivation of p65 which plays a key role in NF-kappa B activation. These observations suggest that triptolide may be a potentially useful drug to enhance TRAIL-induced tumor killing in lung cancer.
Antineoplastic Agents/pharmacology ; Apoptosis/*drug effects ; Cell Line, Tumor ; DNA/metabolism ; Diterpenes/*pharmacology ; Human ; Lung Neoplasms/*metabolism/*pathology ; Membrane Glycoproteins/*pharmacology ; NF-kappa B/*antagonists & inhibitors/metabolism ; Phenanthrenes/*pharmacology ; Tumor Necrosis Factor/*pharmacology

OBJECTIVETo observe the anti-tumor effect of combination TNF-related apoptosis-inducing ligand (TRAIL) with aspirin on liver cancer cell line, SMMC-7721.

METHODSThe survival fraction of SMMC-7721 cells was measured by MTT assay, apoptosis rate and cell cycle was determined by flow cytometry, and the expression of apoptosis-related gene was identified by western blot.

RESULTSThe survival fraction of SMMC-7721 cells treated with 300 ng/ml TRAIL, 3 mmol/L or 10 mmol/L aspirin alone was 82.76%, 81.34% and 71.29% respectively, and the survival fractions of SMMC-7721 cells treated with TRAIL and 3 mmol/L or 10 mmol/L aspirin were 43.54% and 37.8% respectively. The apoptosis rates of SMMC-7721 cells induced by TRAIL and 3 mmol/L or 10 mmol/L aspirin were higher than that induced by TRAIL or aspirin alone (34.76% and 38.56% vs 21.25%, 1.89% and 6.08%), and G0/G1 arrest was observed under TRAIL and aspirin. The expression of Bcl-2 in SMMC-7721 cells treated by 3 mmol/L or 10 mmol/L aspirin decreased markedly, but no effect on Bax.

CONCLUSIONThe cooperative anti-tumor effect of aspirin and TRAIL may be related to the inhibition of the expression of Bcl-2 by aspirin

Antineoplastic Combined Chemotherapy Protocols ; pharmacology ; Apoptosis ; Apoptosis Regulatory Proteins ; Aspirin ; pharmacology ; Cell Survival ; drug effects ; Humans ; Membrane Glycoproteins ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; antagonists & inhibitors ; TNF-Related Apoptosis-Inducing Ligand ; Tumor Cells, Cultured ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo investigate the method and mechanism for exercise-related immunosuppression via the inhibitor of NADPH oxidase diphenyleneiodonium(DPI) and glutamine supplementation and on the function of neutrophils after overtraining.

METHODSFifty male Wistar rats were randomly divided into five groups: a negative control group (C), an overtraining group (E), an overtraining + DPI intervention group (D), an overtraining+ glutamine supplementation group(G) and combined glutamine + DPI intervention group(DG). After 36 - 40 h from the last training, eight rats were randomly selected from each group, and blood was sampled from the orbital vein. ELISAs were used to measure serum cytokine levels and lipid peroxidation in blood plasma. Flow cytometry was used to measure neutrophil respiratory burst and phagocytosis. The activity of NADPH oxidase was assessed by chemiluminescence and the gene expression of gp91(phox) and p47(phox) of the NADPH-oxidase subunit was checked by Western blot.

RESULTSCompared with group C, the plasma concentrations of NO increased in group G, and the NO, cytokine-induced neutrophil chemoattractant (CINC) concentrations in group DG increased significantly. The respiratory burst and phagocytosis function of neutrophils were decreased in group E, but in group DG were increased when compared with those of group E. After overtraining the expression of gp91(phox) and p47(phox) was up regulated in group E. There were no significant changes in other groups except group DG, in which the expression of gp91(phox) was down regulated. Compared with group E, the expression of gp91(phox) and p47(phox) was up regulated in group D, group G and group DG.

CONCLUSIONThe activation of NADPH oxidase is responsible for the production of superoxide anions, which may be related to the decrease in neutrophil function after over training and is the mechanism of exercise-related immunosuppression. The DPI treatment combined glutamine supplementation can reverse the decrease neutrophils function after overtraining in vitro.

Animals ; Dietary Supplements ; Glutamine ; pharmacology ; Hyperkinesis ; physiopathology ; Male ; Membrane Glycoproteins ; metabolism ; NADPH Oxidase 2 ; NADPH Oxidases ; antagonists & inhibitors ; metabolism ; Neutrophils ; metabolism ; physiology ; Onium Compounds ; pharmacology ; Oxidation-Reduction ; Rats ; Rats, Wistar ; Respiratory Burst ; physiology

AIMTo study the antagonistic effect of myricetin on platelet activing factor (PAF).

METHODSThe specific binding of [3H] PAF to rabbit platelet receptor was investigated using radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was assayed by Fura-2 fluorescent technique.

RESULTSThe specific binding inhibition potency of Myr was found to be concentration-dependent. The IC50 of Myr in [3H] PAF 1, 2 and 4 nmol.L-1 were 34.8, 85.7 and 118.6 mumol.L-1, respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration increase were inhibited by Myr in a dose-dependent manner. The IC50 of Myr to inhibit platelet adhesion was 13.1 mumol.L-1.

CONCLUSIONThe specific receptor binding of PAF can be antagonized by myricetin.

Animals ; Calcium ; metabolism ; Flavonoids ; pharmacology ; Male ; Neutrophils ; metabolism ; Platelet Activating Factor ; antagonists & inhibitors ; metabolism ; Platelet Activation ; drug effects ; Platelet Adhesiveness ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Platelet Membrane Glycoproteins ; metabolism ; Rabbits ; Receptors, G-Protein-Coupled ; metabolism

OBJECTIVETo investigate the role of NADPH oxidase (Nox) in the oxidative stress injury of human dermal fibroblasts (HFbs).

METHODSAn oxidative stress injury model was established in HFbs by exposure to H(2)O(2). Normal HFbs and HFbs exposed to H(2)O(2) with and without pretreatment with NADPH oxidase inhibitor were tested for cell viability using MTT assay, and the intracellular reactive oxygen species (ROS) were determined with a DCFH-DA fluorescent probe. Western blotting was used to measure the protein expressions of membrane-bound subunit gp91phox of NADPH oxidase in the cells.

RESULTH(2)O(2) time- and concentration-dependently induced oxidative stress injury in the fibroblasts, causing a reduction of the cell viability to 40% after a 24-h exposure at 700 µmol/L (P<0.05) and an increase of ROS by 2 folds after a 2-h exposure at 700 µmol/L (P<0.05). Compared with the cells with oxidative stress injury, the cells with NADPH oxidase inhibitor pretreatment showed a 20% higher cell viability (P<0.05) and normal ROS level (P<0.05) following H(2)O(2) exposure. Western blotting demonstrated increased expression of gp91phox in the cells exposed to increasing H(2)O(2) concentrations, but gp91phox expression remained normal in cells pretreated with NADPH oxidase inhibitor.

CONCLUSIONH(2)O(2) can induce oxidative stress injury in the fibroblasts by affecting NADPH oxidase, especially its membrane-bound subunit gp91phox.

Cell Survival ; Cells, Cultured ; Fibroblasts ; cytology ; enzymology ; Humans ; Hydrogen Peroxide ; Membrane Glycoproteins ; metabolism ; NADPH Oxidase 2 ; NADPH Oxidases ; antagonists & inhibitors ; metabolism ; Oxidation-Reduction ; Oxidative Stress ; Reactive Oxygen Species ; metabolism