Intravenous Administration of Multiwalled Carbon Nanotubes Aggravates High-Fat Diet-Induced Nonalcoholic Steatohepatitis in Sprague Dawley Rats.

Multiwalled carbon nanotubes (MWCNTs) have been explored in pharmaceutical applications such as tumor targeting and delivery of drugs, in which MWCNTs are given through intravenous injection. However, the biosafety of MWCNTs is of concern for such application. Therefore, in the current study, we used a fatty liver model to investigate the possible toxicity of MWCNTs to the liver, as MWCNTs were retained mainly in the liver of mice after intravenous injection. Male Sprague Dawley rats were used to generate the fatty liver model, and the effects of intravenous administration of MWCNTs on fatty liver were studied. Hematoxylin and eosin staining for hepatocellular anatomy and Masson trichrome staining for hepatic fibrosis were conducted. Histologically, MWCNTs aggravated steatohepatitis with higher nonalcoholic fatty liver disease scores. Analysis of liver injury markers indicated that MWCNTs administration resulted in chronic hepatitis, along with increased liver fat and altered liver oxidation, including the increase of P6 protein and the depletion of glutathione. In conclusion, our results suggest that MWCNTs can aggravate nonalcoholic steatohepatitis in Sprague Dawley rats, and oxidative injury may be involved in this process.

Multiwall carbon nano-onions induce DNA damage and apoptosis in human umbilical vein endothelial cells.

Growing evidence has indicated the potential adverse effects on cardiovascular system of some nanomaterials, including fullerenes. In this study, we have evaluated the biological effects of multiwall carbon nano-onions (MWCNOs) (average size of 31.2 nm, ζ potential of 1.6 mV) on human umbilical vein endothelial cells (HUVECs). It was found that MWCNOs exhibited a dose-dependent inhibitory effect on cell growth; EC50 was 44.12 µg/mL. Thus, three concentrations were chosen (0.2, 1, and 5 µg/mL) for further experiments. Flow cytometry analysis revealed that 1 and 5 µg/mL MWCNOs could induce apoptosis in HUVECs, the apoptotic rates were 12% and 24% at 24 h after exposure. On the other hand, MWCNOs did not affect the cell cycle distribution during 24 h period. Using γH2AX foci formation as an indicator for DNA damage, it was shown that 5 µg/mL MWCNOs can induce γH2AX foci formation in HUVECs at 6, 12, and 24 h after treatment, whereas 0.2 µg/mL MWCNOs induced γH2AX foci formation only at 6 h after treatment. In addition, all three concentrations of MWCNOs induced the generation of reactive oxygen species (ROS), and inhibition of ROS generation can partially decrease the γH2AX foci formation induced by MWCNOs. Taken together, these data first suggested that MWCNOs can induce DNA damage and apoptosis in HUVECs, and that ROS might be involved in this process.

[The pulmonary toxicity study of nano-silica particles on rats through dynamic inhalation].

OBJECTIVE: To investigate the pulmonary toxicity of different concentrations of nano-silica (nano-SiO2) under continuous dynamic inhalation conditions in the rat. METHODS: 48 male Sprague-Dawley rats were randomly divided into four groups, including the dispersant control group (saline) and nano-SiO2 low-dose group (0.3%, w/v), the middle-dose group (1%) and the high-dose group (3%). Animals were sacrificed at 28 d after exposure under continuous dynamic inhalation conditions, and bronchoalveolar lavage fluid (BALF) and lung tissue were collected. And following items were observed: body coefficient, BALF related items (leukocytes and classification, total protein content, LDH activity), lung tissue pathological changes (HE staining), and pulmonary fibrosis forming (collagen fiber VG staining). RESULTS: Compared to the dispersant control group, there was no significant change on lung organ coefficient in Nano-SiO2 group (P < 0.05). The BALF total WBC count in 1% and 3% in nano-SiO2 groups showed higher value than the dispersant control group (P < 0.05). No obvious changes were found on total protein content and LDH activity in nano-SiO2 groups compared to the dispersant control group (P > 0.05). For differential WBC counts, lymphocyte count in BALF in nano-SiO2 groups was significantly decreased (P < 0.05), monocyte and macrophage counts were significantly increased (P < 0.05), but there was no difference on the proportion of neutrophils (P > 0.05). HE staining results showed that the obvious thickening of alveolar wall in nano-SiO2 groups, inflammatory cell infiltration also increased around the bronchial and vascular wall. Lung fibrosis VG staining showed no significant change of collagen fiber distribution. CONCLUSION: Under our experimental conditions, the continuous dynamic inhalation of nano-SiO2 only caused the significant inflammation in rat lungs, pulmonary fibrosis phenomenon could not be observed significantly.

Use of inducible Atg5 deletion and expression cell lines in study of the pro-survival function of autophagy under starvation.

At present the role of autophagy in cell death and cell survival remains controversial, partly owning to the contradictory results from the immortalized mouse embryonic fibroblasts (MEFs) with knockout of different autophagy-related genes (Atg). Here we aimed to reexamine the role of autophagy in cell death under starvation and other stress conditions. First, different clones of Atg5 knockout MEFs had different susceptibility to stress-mediated cell death, indicating that it is the clonal variation, rather than the deficiency of Atg5 or autophagy per se that determines the susceptibility. Next, we tested two cell lines with inducible Atg5 deletion or expression and demonstrated that cells without Atg5 expression were more sensitive to starvation-induced apoptosis. Finally, we found that chloroquine was only effective in sensitizing starvation-induced cell death in Atg5-expressing cells, but not in Atg5-deficient cells. Such observations thus provide unequivocal evidence supporting the pro-survival function of autophagy under starvation. Moreover, our data demonstrate the usefulness of cells with inducible deletion or expression of Atg in the study of autophagy in cell death and cell survival.

[Effects of multi-walled carbon nano onions on platelet adhesion and experimental thrombogenesis in rats].

OBJECTIVE: To observe the effects of multi-walled carbon nano-onions (MWCNOs) on platelet adhesion and experimental thrombosis in rats. METHODS: Experimental rats were randomly divided into sham operation group, solvent group, and MWCNO group, each including 6 ∼ 9 rats. An inverted fluorescence microscope and a flow chamber were used to observe the effects of 20 g/ml MWCNOs on platelet adhesion at shear rates of 500 s(-1) and 1000 s(-1); the experiment was repeated at least three times in each group. A rat model of carotid artery thrombosis was induced by 25% FeCl3, and the effects of 2 mg/kg MWCNOs on the blood flow and wet weight of thrombus per millimeter in the model were observed. RESULTS: When the shear rate was 500 s(-1), the MWCNO group showed a significantly smaller number of adhering platelets than the solvent group (58.3 ± 16.1 platelets/0.01 mm(2) vs 190.1 ± 36.0 platelets/0.01 mm(2)), but the inhibitory effect of MWCNOs on platelet adhesion disappeared as the shear rate increased to 1000 s(-1). The wet weights of thrombus per millimeter at 0 h after injection of a solvent or MWCNOs via the caudal vein were 0.83 ± 0.12 mg/mm in the solvent group and 0.97 ± 0.11 mg/mm in the MWCNO group, and the wet weights of thrombus per millimeter at 12 h after injection were 0.89 ± 0.12 mg/mm in the solvent group and 1.01 ± 0.15 mg/mm in the MWCNO group, exhibiting no significant differences between the two groups (P > 0.05). There were also no significant differences between the two groups in terms of blood flow at 0 h and 12 h after injection (P > 0.05). CONCLUSION: MWCNOs have inhibitory effect on platelet adhesion in vitro, but the injection of MWCNOs via the caudal vein has no effects on the blood flow and wet weight of thrombus per millimeter in experimental thrombosis in rats.

[Pulmonary toxicity in high-fat diet SD rats induced by intravenous injection of multi-walled carbon nanotubes].

OBJECTIVE: To observe the pulmonary toxicity of multi-walled carbon nanotubes (MWCNTs) in high-fat diet SD rats. METHODS: One hundred forty male SD rats were randomly divided into 6 groups. The normal control group, high-fat diet model group, vehicle group, and group treated with low dose of MWCNTs consisted of 30 rats, respectively, which were divided in 3 subgroups (10 rats each subgroup), respectively. The groups treated with medium and high loses of MWCNTs consisted of 10 rats, respectively. All the animals were exposed to high-fat-diet except for the control group which was given with normal diet. Before intravenous exposure, the high-fat diet model group, vehicle group, and three MWCNTs treated groups were gavaged with 700 thousand U/kg Vit D3 for three days, then given with high-fat-diet. The vehicle group was exposed to normal saline containing 1% Tween 80 and the low exposure group was exposed to MWCNTs at the dose of 50 µg/kg by tail vein injection twice a week for 8, 12 or 16 weeks. Other tow exposure groups were exposed to MWCNTs at the doses of 100, and 200 µg/kg by tail vein injection twice a week, respectively for 16 weeks. The lungs were from the executed rats, the lung indexes were calculated, the pathological changes of lungs were examined under light microscope after HE staining. qRT-PCR assay was utilized to detect the expression levels of pro-inflammation cytokines IL-1ß (IL-1ß) and TNF-α mRNA in the lungs. RESULTS: As compared with the vehicle group, the lung indexes in groups exposed to 100 and 200 µg/kg MWCNTs increased significantly (P < 0.05). It was found under light microscope that the MWCNTs were accumulated in lungs of three exposure groups in 16 weeks after exposure, including pneumorrhagia, alveolar walls thicken, fibrosis, and granulomas. As compared with the vehicle group, the levels of IL-1ß mRNA in group exposed to 50 µg/kg MWCNTs for 12 weeks and the groups exposed to 50, 100 and 200 µg/kg MWCNTs for 16 weeks decreased significantly (P < 0.05). As compared with the vehicle group, the levels of TNF-α mRNA in the groups exposed to 50 µg/kg MWCNTs for 8 and 16 weeks increased significantly (P < 0.05), the level of TNF-α mRNA in the groups exposed to 50 µg/kg MWCNTs for 12 weeks decreased significantly (P < 0.05). As compared with the vehicle group, the level of TNF-α mRNA in the groups exposed to 200 µg/kg MWCNTs for 16 weeks reduced significantly (P < 0.05). CONCLUSION: The MWCNTs accumulation and chronic inflammatory changes were found in the lungs of rats exposed to MWCNTs by tail vein injection.

Cytotoxic and genotoxic effects of multi-wall carbon nanotubes on human umbilical vein endothelial cells in vitro.

Carbon nanomaterials have multiple applications in various areas. However, it has been suggested that exposure to nanoparticles may be a risk for the development of vascular diseases due to injury and dysfunction of the vascular endothelium. Therefore, in the present study, the cytotoxic and genotoxic effects of multi-wall carbon nanotubes (MWCNTs) on human umbilical vein endothelial cells (HUVECs) were evaluated. Optical and transmission electronic microscopy (TEM) study showed that MWCNTs were able to enter cells rapidly, distribute in the cytoplasm and intracellular vesicles and induce morphological changes. Exposure to MWCNTs reduced the viability of HUVECs, and induced apoptosis in HUVECs. Furthermore, MWCNTs could cause DNA damage as indicated by the formation of γH2AX foci. MWCNTs also affected cellular redox status, e.g., increasing intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels, as well as altering superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) levels. On the other hand, the free radical scavenger N-acetyl-l-cysteine (NAC) preincubation can inhibit the cytotoxic and genotoxic effects of MWCNTs. Taken together, these results demonstrated that MWCNTs could induce cytotoxic and genotoxic effects in HUVECs, probably through oxidative damage pathways.

[Oxidative damage of single-walled carbon nanotubes in striaturn and hippocampi of mice].

OBJECTIVE: To study the oxidative damage of SWCNTs in striaturn and hippocampi of mice. METHODS: Forty male ICR mice were divided into experiment group (12.5 mg/kg SWCNTs) and control group (saline containing 0.1% Tween80) randomly. Each group was subdivided into 1, 7, 14 and 28 days group, 5 mice in each subgroup, then treated with tail intravenous injection for 5 continuous days. The striatum and hippocampus were isolated on the ice bath and homogenized in saline. SOD, GSH-Px, and MDA in the supernatants were measured with xanthine oxidize, GSH consumption in enzymatic reaction and TBA methods. RESULTS: After exposure to 12.5 mg/kg SWCNTs for 5 d, SOD activity in striaturn and hippocampi decreased on 1st day and reached the minimum on 7th day, then increased gradually. The SOD activity in the SWCNTs treatment groups on 7th day were significantly decreased when compared to control (P < 0.05). Comparison with control group, GSH-Px activity in striaturn obviously decreased on 7th day then increased on 14th day, the difference between 7th day and 14th day was significantly (P < 0.05). GHS-Px activity in the hippocampi in SWCNTs group on 7th day and 14th day was significantly lower than that in control group (P < 0.05), then increased to the level of control group on 28th day. MDA contents of striaturn and hippocampi in SWCNTs group reduced on 1st day, then gradually increased on 7th day and 14th day, then reduced, MDA contents on7th day and 14th day n SWCNTs group were significantly higher than that in control group (P < 0.05). CONCLUSIONS: The results of present study indicated that SWCNTs could decrease antioxidase activity and increase the Lipid peroxide in striaturn and hippocampi of mice.

[Effects of multiwall carbon nano-onions on platelet aggregation and hemostatic function].

OBJECTIVE: To observe the effects of multiwall carbon nano-onions (MWCNOs) on platelet aggregation and hemostatic function. METHODS: The platelet aggregation was determined with Born's method at different concentration of MWCNOs (0, 0.2, 2.0, 20.0 microg/ml) in vitro. Twenty male SD rats were randomly divided into 4 groups which were exposed to 0, 2, 4 and 8 mg/kg MWCNOs, respectively. Then platelet count, platelet aggregation, activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), bleeding time (BT) and platelet count (PC) were measured at 12 h after receiving tail intravenous injection of MWCNOs. The effects of MWCNOs (4 mg/kg) on platelet aggregation and platelet count at different time points were observed. RESULTS: In vitro, MWCNOs exhibited the potent inhibitory effects on rat platelet aggregation caused by ADP in a concentration-dependent manner. The platelet aggregation in the highest dosage of 20.0 microg/ml group was 50.0% +/- 6.9% which was significantly lower than that (73.2% +/- 4.3%) in control group (P<0.01). In vivo, the highest inhibitory was up to 20.4%, but there was no significant difference, as compared with control group. MWCNOs did not affect the APTT, PT, TT, BT and PC. CONCLUSION: Under this experimental condition, MWCNOs might inhibit platelet aggregation but not affect hemostatic function.

[Antiandrogenic effects of cypermethrin and beta-cypermethrin].

OBJECTIVE: To investigate the antiandrogenic activities of cypermethrin and beta-cypermethrin in vitro and in vivo. METHODS: Transcriptional activation assay based on MDA-kb2 cell was used to determine the antiandrogenic effect of cypermethrin and beta-cypermethrin in vitro. The cells were treated by 10(-8), 10(-7), 10(-6) and 10(-5) mol/L of cypermethrin and beta-cypermethrin with 1.0 nmol/L DHT at the same time. The effects of antagonism towards the androgenic receptor were studied. In in vivo assays, Hershberger assay was used to determine the antiandrogenic activities of cypermethrin and beta-cypermethrin. Six-week-old castrated male SD rats were administered by cypermethrin (7, 21 and 63 mg/kg) and beta-cypermethrin (6, 18 and 54 mg/kg). After 7-day treatments, all rats were euthanized and androgen-responsive tissues were excised and weighed respectively. RESULTS: The in vitro experiments showed that 10(-6) and 10(-5) mol/L cypermethrin could inhibit significantly the antagonism activity towards the androgenic receptor of DHT. In in vivo tests, the weight of seminal vesicle, ventral prostate, dorsolateral prostate and preputial glands in the 63 mg/kg cypermethrin [(52.8 +/- 7.1), (42.4 +/- 8.9), (36.6 +/- 4.5) and (43.4 +/- 11.1) mg] decreased significantly compared with those in the control group. In 21 mg/kg cypermethrin treated group only the weights of ventral prostate and dorsolateral prostate decreased significantly, and in 7 mg/kg cypermethrin only the weight of dorsolateral prostate decreased (P < 0.05). For beta-cypermethrin, any antiandrogen effect in in vivo and in vitro experiments was not found in all the groups. CONCLUSION: Cypermethrin is a moderate antiandrogen that elicits antiandrogenic effects at least partly by antagonizing AR and beta-cypermethrin is not an antiandrogen in our experiments.

[Study of toxicity to rats induced by nanosized SiO2 and standard SiO2].

OBJECTIVE: To study the pulmonary toxicity to rats induced by the nanosized SiO(2) or the standard SiO(2). METHODS: Seventy-two male SD rats were divided into three groups: the nanosized SiO(2) group, the standard SiO(2) group and the control group. 24 rats each group. The nanosized SiO(2) group and the standard SiO(2) group were instilled intratracheally with 0.5 ml suspension of 0.6 mg/ml nanosized SiO(2) or standard SiO(2) respectively while the control group was instilled with 0.5 ml physiological saline. On the 3rd, 7th, 14th, and 28th day after exposure, six rats were sacrificed at each time point and the total white cells counts and total protein in BALF and the histopathological changes were observed. The pulmonary toxicities of the two SiO(2) dusts were compared. RESULTS: Nanosized SiO(2) caused significant increase at 3rd, 7th, 14th day after the exposure [(16.0 +/- 6.0) x 10(6), (11.1 +/- 4.0) x 10(6), (12.2 +/- 4.6) x 10(6)] compared with saline (P < 0.05 or P < 0.01) in the total numbers of white cells and on the 3rd after the exposure compared with standard SiO(2) [(5.7 +/- 3.7) x 10(6), P < 0.01]. Meanwhile, Nanosized SiO(2) significantly increased the total protein on the 14th, 28th day after the exposure (0.41 +/- 0.14, 0.41 +/- 0.19 g/L) compared with saline or standard SiO(2) and nanosized SiO(2) on the 3rd, 7th day after the exposure (P < 0.05 or P < 0.01). Nanosized SiO(2)-treated rats showed marked white cell infiltration in alveolar space or around brondum the blood vessel. Standard SiO(2) caused similar but less severe responses compared with nanosized SiO(2). Van Gieson's-stained sections showed no significant fibrosis in these dust-exposed rats at 28th day after the exposure. CONCLUSION: Nanosized SiO(2) can cause severer and longer pulmonary toxicity in rats than standard SiO(2). The pulmonary particle load threshold of nanosized SiO(2) may be lower than that of standard SiO(2).

[Research progress on anti-tumor effects of luteolin].

Luteolin is an important member of the flavonoid family. It has been reported that luteolin can inhibit the proliferation of serials of tumor cells including solid tumor, ascites cancer and human myeloid leukemia. Luteolin can also sensitize a number of apoptosis-inducing factors by unique mechanisms.

[Kaempferol activates human steroid and xenobiotic receptor-mediated cytochrome P450 3A4 transcription].

OBJECTIVE: To investigate whether kaempferol stimulates pregnane X receptor (PXR)-mediated transcription of CYP3A4. METHODS: Transient cotransfection reporter gene assay was performed with PXR expression plasmid and a reporter plasmid containing the XREs in the CYP3A4 gene promoter in HepG(2)cells. RESULTS: Kaempferol activated PXR-mediated transcription of CYP3A4 in a dose, time-dependent manner. In the dose-response study, kaempferol exposure at concentrations of 1.0 x 10(-3), 1.0 x 10(-2), 0.1, 1.0 and 10.0 mol/L for 24 h increased CYP3A4 transcription by (1.31+/-0.27), (1.45+/-0.36), (1.96+/-0.50), (2.90+/-1.07) and (7.93+/-0.75) fold, respectively compared with 0.1% DMSO (P<0.05). The results from time-course study showed that after 48 h exposure 1.0 and 10.0 mol/L of kaempferol enhanced the transcription of CYP3A4 by (3.73+/-1.21) fold and (8.42+/-1.47) fold, respectively. CONCLUSION: Kaempferol may be a human CYP3A4 gene inducer through PXR, and may affect the metabolism of a large number of substrates of CYP3A4 simultaneously taken.

[Human pregnane X receptor-mediated transcriptional regulation of cytochrome P450 3A4 by some phytochemicals].

OBJECTIVE: To test the effect on human pregnane X receptor (hPXR)-mediated transcription regulation of CYP3A4 by five selected phytochemicals. METHODS: Transient cotransfection reporter gene assays in HepG(2) cells were performed with the hPXR expression plasmid and the reporter gene plasmid which contains XRE in the promoter of CYP3A4 linked to luciferase. RESULTS: In the dose-effect study, soybean isoflavone, luteolin and curcumin induced the CYP3A4 transcription via PXR in an evident dose-dependent manner, but isorhamnetin and rutin did not. The inducibility of soybean isoflavone, luteolin and curcumin was also increased in concentrations between 1 micromol/L and 50 micromol/L, 24 h after induction, 50 micromol/L soybean isoflavone, luteolin and curcumin exhibited a 5.46-fold, 2.87-fold, and 2.07-fold increase respectively, compared with 0.1% DMSO treated cells. In the time-effect study, 10 micromol/L and 50 micromol/L soybean isoflavone, luteolin and curcumin induced CYP3A4 transcription between 12 h and 48 h, the strongest induction appeared in 48 h. 48 h after induction, 50 micromol/L soybean isoflavone, luteolin and curcumin exhibited a 6.72-fold, 3.24-fold, and 2.13-fold increase respectively, compared with 0.1% DMSO treated cells. CONCLUSION: Three phytochemicals, i.e. soybean isoflavone, luteolin and curcumin stimulate the PXR-mediated transcription of CYP3A4. Isorhamnetin and rutin have no effect on the CYP3A4 transcription via PXR.

[Effects of kaempferol and quercetin on cytochrome 450 activities in primarily cultured rat hepatocytes].

OBJECTIVE: To observe the effects of kaempferol and quercetin on the activity of cytochrome P450 in rat hepatocytes. METHODS: Primarily cultured rat hepatocytes were exposed to kaempferol or quercetin in concentrations of 0.1, 1, 10 micromol/L for 12 h, 24 h and 48 h. Hepatocytes CYP isoemzymes-erythromycin N-demethylase (ERND) and aminopyrine N-demethylase (ADM) activities were determined by Nash methods. Erythromycin (10 micromol/L) was used as positive control and DMSO(0.1%) as solvent control. RESULTS: Kaempferol and quercetin inhibited ENRD activity in a dose-and time-dependent manner. In dose-response study, the ENRD activities in kaempferol (0.1,1 and 10 micromol/L) treated groups were (0.088+/-0.008), (0.074+/-0.006) and (0.041+/-0.003)micromol/(mg.min(-1)), respectively. ENRD activity in quercetin treated groups at the same concentrations were (0.082+/-0.007), (0.063+/-0.007) and (0.034+/-0.005) micromol/(mg.min(-1)), respectively. In time-courses study, the ENRD activity exposed to 10 micromol/L kaempferol or quercetin for 12 h and 48 h were (0.053+/-0.006) and (0.037+/-0.007) micromol/(mg.min(-1)), or (0.067+/-0.005) and (0.032+/-0.004) micromol/(mg.min(-1)). ADM activity was inhibited only by kaempferol in 10 mol/L at 24 h, but was not significantly altered by quercetin at any concentration tested. CONCLUSION: In the present condition, kaempferol and quercetin act as potential CYP3A4 inhibitors as they can significantly inhibit ENRD in primarily cultured rat hepatocytes.

[Effect of kaempferol on the pharmacokinetics of nifedipine in rats].

OBJECTIVE: To investigate the effect of kaempferol on the pharmacokinetics of nifedipine (NFP) in rats. METHODS: Twenty male SD rats, weighing 220-260 g, were distributed randomly into 4 groups. The animals were fasted, but allowed free access to water for 12 h before the administration of drugs. NFP dissolved in corn oil was administered via gastric intubation to the rats in control group at a dose of 10 mg/kg. Kaempferol was administered orally to the other three groups with dose of 5, 10, 15 mg/kg, respectively, followed by oral administration of NFP 10 mg/kg. Blood samples were collected through tail vein in heparinized plastic microcentrifuge tubes before and after drug administration. The plasma concentration of NFP was monitored with reversed phase high-performance liquid chromatography (RP-HPLC). Nimodipine was used as the internal standard. Statistical data evaluation was performed with Student's t-test and one-way analysis of variances. RESULTS: The maximal plasma concentration (C(max)) of the three treated groups were 0.51, 0.70 and 0.81 microg/ml, respectively. The area under the concentration-time curve (AUC(0-8)) were 1.81, 2.83 and 3.63 microg/(h.ml(-1)), respectively. The C(max), AUC(0-8) and the mean retention time (MRT(0-8)) of NFP were significantly increased by simultaneous oral treatment with kaempferol (P<0.01). On the other hand, there were no significant differences in the mean peak value time in plasma (T(max)) and the elimination half-life (t1/2(ke)) between the control and the treated groups. CONCLUSION: The concomitant oral use of kaempferol with NFP may influence the pharmacokinetic parameters of NFP in rats, which suggests that kaempferol might reduce the first-pass metabolism of NFP.

FBS or BSA Inhibits EGCG Induced Cell Death through Covalent Binding and the Reduction of Intracellular ROS Production.

Previously we have shown that (-)-epigallocatechin gallate (EGCG) can induce nonapoptotic cell death in human hepatoma HepG2 cells only under serum-free condition. However, the underlying mechanism for serum in determining the cell fate remains to be answered. The effects of fetal bovine serum (FBS) and its major component bovine serum albumin (BSA) on EGCG-induced cell death were investigated in this study. It was found that BSA, just like FBS, can protect cells from EGCG-induced cell death in a dose-dependent manner. Detailed analysis revealed that both FBS and BSA inhibited generation of ROS to protect against toxicity of EGCG. Furthermore, EGCG was shown to bind to certain cellular proteins including caspase-3, PARP, and α-tubulin, but not LC3 nor ß-actin, which formed EGCG-protein complexes that were inseparable by SDS-gel. On the other hand, addition of FBS or BSA to culture medium can block the binding of EGCG to these proteins. In silico docking analysis results suggested that BSA had a stronger affinity to EGCG than the other proteins. Taken together, these data indicated that the protective effect of FBS and BSA against EGCG-induced cell death could be due to (1) the decreased generation of ROS and (2) the competitive binding of BSA to EGCG.

The coordinated regulation of Na+ and K+ in Hordeum brevisubulatum responding to time of salt stress.

Hordeum brevisubulatum, called as wild barley, is a useful monocotyledonous halophyte for soil improvement in northern China. Although previously studied, its main salt tolerance mechanism remained controversial. The current work showed that shoot Na+ concentration was increased rapidly with stress time and significantly higher than in wheat during 0-168h of 100mM NaCl treatment. Similar results were also found under 25 and 50mM NaCl treatments. Even K+ was increased from 0.01 to 50mM in the cultural solution, no significant effect was found on tissue Na+ concentrations. Interestingly, shoot growth was improved, and stronger root activity was maintained in H. brevisubulatum compared with wheat after 7days treatment of 100mM NaCl. To investigate the long-term stress impact on tissue Na+, 100mM NaCl was prolonged to 60 days. The maximum values of Na+ concentrations were observed at 7th in shoot and 14th day in roots, respectively, and then decreased gradually. Micro-electrode ion flux estimation was used and it was found that increasing Na+ efflux while maintaining K+ influx were the major strategies to reduce the Na+ concentration during long-term salt stress. Moreover, leaf Na+ secretions showed little contribution to the tissue Na+ decrease. Thereby, the physiological mechanism for H. brevisubulatum to survive from long-term salt stress was proposed that rapid Na+ accumulation occurred in the shoot to respond the initial salt shock, then Na+ efflux was triggered and K+ influx was activated to maintain a stable K+/Na+ ratio in tissues.

[Effects of phytoestrogens on gap junctional intercellular communication].

OBJECTIVE: To observe effects of phytoestrogens quercetin (QC), Genistein (GEN), coumestrol (COM), and enterolactone (ENL) on gap junctional intercellular communication (GJIC) in HaCaT cells. METHODS: HaCaT cells were exposed to QC, GEN, COM, and ENL at 0.1, 1.0, 10.0 and 100.0 micromol/L for 24 hours. The effects of phytoestrogens on GJIC were determined by fluorescence redistribution after photobleaching (FRAP) technique of using a laser scanning confocal microscope (LSCM). RESULTS: QC did not affect the GJIC at 0.1-10.0 micromol/L, whereas, GEN, COM, and ENL exhibited inhibition on the GJIC in some extent at 0.1-10.0 micromol/L without showing significant cytotoxicity. The ratio of fluorescence recovery were between 31.77% to 37.06%, which were significantly decreased compared the vehicle control (44.74%). CONCLUSION: The phytoestrogens GEN, COM, and ENL, but not QC, could inhibit the GJIC function in HaCaT cells at concentrations could be reached in human serum in some instance, indicating they could, under certain conditions, be cancer promoters. Therefore, it should be prudent to use these chemicals as pharmaceuticals or dietary supplements.

[Study on the transcriptional modulation of cytochrome P450 3A4 expression by zearalenone].

OBJECTIVE: To study whether zearalenone (ZEA), a fungal estrogen, can transcriptionally up-regulate the expression of cytochrome 450 3A4 (CYP3A4) transcription by activating human steroid hormone and xenobiotic receptor (SXR). METHOD: Transient cotransfection reporter gene assays were performed with human SXR expression plasmid and a reporter plasmid containing the SXR in the CYP3A4 gene promoter in HepG(2) cells. RESULTS: The transcriptional induction of CYP3A4 by ZEA with a dose, time-dependent manner. ZEA at the concentrations of 0.01, 0.10, 1.00 and 10.00 micromol/L, respectively, could induce CYP3A4 with (1.50 +/- 0.21), (1.66 +/- 0.27), (3.04 +/- 0.82) and (3.96 +/- 1.16) folds, as compared with 0.1% DMSO. Results from a time-dependent study show that 1.00 and 10.00 micromol/L of ZEA for 12 to 48 hours could enhance the transcription of CYP3A4 with (3.69 +/- 1.34) and (5.18 +/- 1.50) folds, and 10.00 micromol/L of ZEA for 48 hours could induce the CYP3A4 gene expression (5.18 +/- 1.50) folds, as compared with 0.1% DMSO by activating human SXR. CONCLUSION: ZEA could induce the expression of the CYP3A4 gene transcription through activating SXR, possibly by affecting the other substrates of the CYP3A4, especially affecting the metabolism of drugs in the body.