OBJECTIVE: To study the effect of dexamethasone (DEX) on the expression of Dynein heavy chain (DHC) and Dynactin in the cytoplasm of fetal rat cerebral cortical neurons cultured METHODS: Primary cerebral cortical neurons of fetal rats were cultured RESULTS: There was no significant difference in the mRNA expression levels of DHC and Dynactin among the three groups at all time points ( CONCLUSIONS DEX affects the protein expression of DHC and Dynactin in the fetal rat cerebral cortical neurons cultured
Animals ; Cytoplasm ; Dexamethasone/pharmacology* ; Dynactin Complex/genetics* ; Dyneins ; Neurons ; Rats

BACKGROUNDGlucocorticoid is speculated to be able to have Aspergillus fumigatus (A. fumigatus) being more susceptible to reactive oxygen species (ROS) by inhibiting Afyap1, the transcription factor activating protein-1 (AP-1) homologue in A. fumigatus, which may provide a clue to expand the clinical use of glucocorticoid in patients with fungal infections. In this study, we used dexamethasone to determine the direct effect on oxidative killing susceptibility of A. fumigatus in vitro, as well as the expression level of Afyap1 gene and its target genes (catalase and superoxide dismutase (SOD) genes).

METHODSA. fumigatus spores were treated with different concentrations (0, 0.02, 0.2 mg/ml) of glucocorticoids and assigned to four groups (A: 0.5 hour, B: 2 hours, C: 7 hours, D: 16 hours) according to the time of treatment. The H2O2 oxidative killing assay was done, using the standard method-spot test, in each group of A. fumigatus. We measured the oxidative killing susceptibility as well as the expression level of the gene Afyap1, CATA, SOD1 and SOD2 in A. fumigatus at each group. The antifungal susceptibility to itraconazole and amphotericin B in each group of A. fumigatus was also measured with M38-A2 method.

RESULTSThe oxidative killing susceptibility of A. fumigatus was increased, consistent with the reduction of Afyap1, CATA, SOD1 and SOD2 gene expression level after being treated with dexamethasone for 0.5 hours. However, these observations were disappeared along with being treated for longer time. The antifungal susceptibility to itraconazole and amphotericin B in the A. fumigatus strains treated with dexamethasone indicated no change, compared with those without dexamethasone treatment.

CONCLUSIONDexamethasone can have A. fumigatus being more susceptible to ROS when treated for shorter period (0.5 to 2 hours) via the reduction of Afyap1 gene expression as well as the down-stream enzyme-coding gene expression.

Aspergillus fumigatus ; drug effects ; genetics ; metabolism ; Dexamethasone ; pharmacology ; Fungal Proteins ; genetics ; metabolism ; Hydrogen Peroxide ; pharmacology

OBJECTIVETo investigate the effect of bortezomib (Bor) alone or in combination with As(2)O(3) (ATO) and/or dexamethasone (DXM) on proliferation and apoptosis in KM3 human multiple myeloma cell line KM3.

METHODSKM3 cells were cultured with different concentrations of Bor and ATO and/or DXM in combination or Bor, ATO, DXM alone for different times. Cell proliferation was assayed by MTT assay, and IC(50) was calculated. Cell morphology was observed with light and electric microscopy. The agarose gel electrophoresis was used to evaluate DNA content, and the flow cytometry was used to exam Annexin V-FITC/PI stain.

RESULTSBor, ATO and DXM inhibited KM3 cell proliferation in a time-and dose-dependent manner with the IC(50) of 0.27, 3.10 and 8.01 micromol/L, respectively. The inhibition rate of KM3 cells by Bor plus ATO and DXM was significantly higher than Bor plus ATO or DXM \[(34.51 +/- 0.51)% vs (25.39 +/- 0.90)% and (34.51 +/- 0.51)% vs (23.80 +/- 0.78)% respectively\]. Typical morphology for apoptosis and DNA ladder were observed in KM3 cell treated with 0.25 micromol/L Bor for 48 h, by Annexin V positivity. The apoptosis rate induced by Bor plus both ATO and DXM was higher than that induced by Bor plus DXM.

CONCLUSIONBor can inhibit the proliferation and induce apoptosis of KM3 cells. Bor enhances the inhibitory effect of ATO and DXM on the growth of KM3 cell. ATO enhances the apoptosis effects of Bor and DXM on KM3 cells.

Apoptosis ; drug effects ; Boronic Acids ; pharmacology ; Bortezomib ; Cell Line, Tumor ; Dexamethasone ; pharmacology ; Humans ; Multiple Myeloma ; metabolism

BACKGROUNDHaptoglobin (Hp) is one of the acute-phase proteins. Recent studies have demonstrated that Hp exerts immunoregulatory and anti-inflammatory actions and may be one of the inhibitory factors of immune reactions in the skin. In this study we investigated the regulation of Hp expression in a human keratinocyte cell line HaCaT by various cytokines and glucocorticoid.

METHODSHaCaT cells were cultured with IL-6 (50 ng/ml), TNF-alpha (20 ng/ml), IFN-gamma (20 ng/ml) or IL-4 (20 ng/ml) with or without 1 micromol/L dexamethasone in 6-well plates for 12, 24 and 48 hours. Both the cells and the supernatants were collected to detect the changes of Hp expression by reverse-transcription PCR, ELISA and immunohistochemistry.

RESULTSThe results showed that Hp expression were elevated at both the mRNA and protein level by the combination of IL-6, TNF-alpha or IL-4 with dexamethasone, whereas the three cytokines alone did not upregulate the Hp expression. IFN-gamma showed no effect on the Hp expression in HaCaT cells.

CONCLUSIONSThese findings suggest that different inflammatory cytokines as well as glucocorticoid may be involved in the regulation of Hp expression in keratinocytes, and this may be one of the negative feedback mechanisms in inflammatory skin diseases.

Cell Line ; Dexamethasone ; pharmacology ; Glucocorticoids ; pharmacology ; Haptoglobins ; analysis ; Humans ; Interferon-gamma ; pharmacology ; Interleukin-4 ; pharmacology ; Interleukin-6 ; pharmacology ; Keratinocytes ; chemistry ; drug effects ; Tumor Necrosis Factor-alpha ; pharmacology

To investigate the influence of As2O3, dexamethasone (Dex) and thalidomide (Thal) on apoptosis-induced myeloma cell line U266 cytoplasmic calcium concentrations ([Ca2+]i), U266 cells were incubated in the culture of RPMI 1640 with 15% FBS in 24-well plate and exposed to different concentrations of As2O3, Dex and Thal for 8 hours, respectively, then cell apoptosis was analyzed by fluorescence microscopy and flow cytometry (FCM) with Annexin V-FITC/PI double staining, and cytoplasmic free calcium were detected on FCM through Fluo-3/AM loading. The results indicated that (1) apoptotic cells were gradually increased with enhancement of As2O3, Dex and Thal concentrations; (2) apoptotic cell rates increased from 0.56% in control to 31.54%, 28.35% and 21.97% respectively after treatment with As2O3, Dex and Thal; (3) As2O3, Dex induced U266 cell apoptosis accompanied with raise of [Ca2+]i; (4) [Ca2+]i had no statistically significant changes in Thal-induced apoptotic U266 cells. It is concluded that the raise of [Ca2+]i is one of the mechanisms for As2O3 and Dex-induced U266 cells apoptosis, whereas Thal-induced U266 apoptosis has no significant relation to [Ca2+]i changes.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; Calcium ; metabolism ; Cell Line, Tumor ; Cytoplasm ; metabolism ; Dexamethasone ; pharmacology ; Humans ; Multiple Myeloma ; pathology ; Oxides ; pharmacology ; Thalidomide ; pharmacology

OBJECTIVEThis clinical study was to find an effective method to prevent flap from necrosis.

METHODSWhen a flap showed blood flow problems, dexamethasone of 0.3 mg/kg was given intravenously for 2 days. Then the dose was decreased to 0.2 mg/kg at the third and the fourth day. At the fifth and the sixth day, dexamethasone of 0.1 mg/kg was given.

RESULTSA total of 51 flaps with blood flow problems was treated with this method. Thirty of them recovered completely; 18 survived mostly and 3 failed.

CONCLUSIONEarly application of dexamethasone can effectively ameliorate blood flow problems of the flap.

Adolescent ; Adult ; Dexamethasone ; pharmacology ; therapeutic use ; Female ; Humans ; Male ; Middle Aged ; Necrosis ; Surgical Flaps ; pathology

OBJECTIVEThis study aimed to explore the effects of hyperoxia on the development of fetal lung by investigating the changes of morphological and cell proliferation induced by hyperoxia in cultured fetal lungs as well as the effects of dexamethasone on hyperoxia-exposed lungs.

METHODSHuman fetal lung explants at the pseudoglandular stage of development were cultured randomly either in normoxia (21% O2/5% CO2) or hyperoxia (95% O2/5% CO2) for 72 hrs. Dexamethasone was added into the feeding medium at the concentration of 10(-6)M. Harvested tissues were stained for pancytokeratin to identify epithelial cells, with Ki-67 as a marker of proliferation. The effects of lung morphometry were analyzed using computer assisted image analysis. The mean airway thickness, the proportion of the surface area occupied by airways, the mean airway surface area and the index of the epithelium proliferation were measured.

RESULTSThe lung architectures remained unchanged after 72 hrs normoxia culture, whereas hyperoxia culture resulted in significant dilation of airways and thinning of epithelium, with the surface area of airways of 6662 microm(2) vs 2728 microm(2) and the thickness of airways of 7.8 microm vs 8.1 microm (P < 0.05). Hyperoxia culture also resulted in an increase in the proportion of the surface area occupied by airways than normoxia culture (35.2% vs 23.4%; P < 0.05). The surface area of airways (3174 microm(2)) and the proportion of the surface area occupied by airways (23.9%) decreased significantly in hyperoxia-cultured lungs after dexamethasone administration (P < 0.05). The epithelium proliferation index in hyperoxia-cultured lungs (21.8%) was higher than that in normoxia-cultured lungs (5.1%) and dexamethasone-treated hyperoxia-cultured lungs (7.4%) (P < 0.05).

CONCLUSIONSThe exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs with higher epithelium proliferation index. Dexamethasone may inhibit the effects induced by hyperoxia.

Cell Differentiation ; drug effects ; Dexamethasone ; pharmacology ; Female ; Humans ; Hyperoxia ; pathology ; Lung ; drug effects ; embryology ; pathology ; Pregnancy

BACKGROUNDThe efficacies of current treatments for invasive aspergillus (IA) are unsatisfactory and new therapeutic targets or regimens to treat IA are urgently needed. Previous studies have indicated that the ability of conidia to invade host cells is critical in IA development and fibronectin has a hand in the conidia adherence process. In the clinical setting, many patients who receive glucocorticoid for extended periods are susceptible to Aspergillus fumigatus (A. fumigatus) infection, for this reason we investigated the effect of glucocorticoid on conidia invasiveness by comparing the invasiveness of A. fumigatus conidia in the type II human alveolar cell line (A549) cultured with different concentrations of dexamethasone. We also explored the relationships between dexamethasone and fibronectin expression.

METHODSFollowing culture with anti-fibronectin antibodies and/or dexamethasone, type II human alveolar A549 cells were infected with conidia of A. fumigatus. After 4 hours, the extracellular free conidia were washed away and the remaining immobilized conidia were released using Triton-X 100 and quantified by counting the colony-forming units. The invasiveness of conidia was measured by calculating the invasion rate (%). The transcription of the fibronectin gene in cells cultured with different concentrations of dexamethasone for 24 hours was tested by fluorogenic quantitative RT-PCR while the expression of fibronectinin cells cultured for 48 hours was tested by Western blotting and immunocytochemistry.

RESULTSA significant reduction in the invasiveness of conidia was seen in the cells cultured with anti-fibronectin antibody ((14.42 ± 1.68)% vs. (19.17 ± 2.53)%, P < 0.05), but no significant difference was observed in cells cultured with a combination of anti-fibronectin antibody and dexamethasone (6.37 ± 10(-5) mol/L). There was no correlation between the dexamethasone concentration and the invasiveness of conidia after dexamethasone pretreatment of cells for 4 hours. In contrast, after pretreated for 24 hours, the invasiveness of conidia in the presence of 6.37×10(-5) mol/L dexamethasone ((24.66 ± 2.41)%) was higher than for the control ((19.17 ± 2.53)%) and the 0.25×10(-5) mol/L group ((19.93 ± 3.06)%), and the invasiveness in the 1.27×10(-5) mol/L group ((22.47 ± 2.46)%) was also higher than in the control, P < 0.05. The relative transcripts of the fibronectin gene after exposure to 6.37×10(-5) mol/L dexamethasone (9.19×10(-3)±1.2×10(-3)) was higher than for the control (4.61×10(-3)± 1.54×10(-3)) and the 0.25×10(-5) mol/L group (6.20×10(-3)± 1.93×10(-3)), and expression in the 1.27×10(-5) mol/L group (7.94×10(-3)± 2.24×10(-3)) was also higher than for the control, P < 0.05. High concentrations of dexamethasone promoted fibronectin production after culture for 48 hours.

CONCLUSIONSDexamethasone can increase invasiveness of A. fumigatus conidia by promoting fibronectin expression. This may partially explain why patients who are given large doses of glucocorticoids for extended periods are more susceptible to A. fumigatus infection.

Aspergillus fumigatus ; pathogenicity ; Cell Line, Tumor ; Dexamethasone ; pharmacology ; Fibronectins ; genetics ; metabolism ; Gene Expression ; drug effects ; Humans

The effect of dexamethasone (10(-5)M) and epinephrine (10(-6)M) on the biosynthesis of metallothionein (MT) in the perfused rat liver was investigated. MT synthesis was determined by measuring the incorporation of 14C-L-aspartic acid into liver MT fraction after the perfusion for five hours of isolated liver by artificial blood containing 14C-L-U-aspartic acid (0.2uci) with dexamethasone or epinephrine. MT was isolated by Sephadex G-75 column chromatography and DEAE Sephadex column chromatography. Incorporation of radioactive 14C into the MT fraction of perfused liver cytosol (9.0grams of liver) from dexamethasone treated, epinephrine treated and control groups were, respective1y, 0.72, 0.34 and 0.33% of total radioactivity infused. Total protein content in the MT fraction of liver perfused with dexamethasone and epinephrine were 0.80, 0.64mg/g liver compared to 0.52mg/g liver in the control. MT, a protein having a high content of cystein and metals is synthesized in the perfused rat liver and its induction is stimulated by dexamethasone, while epinephrine increased the accumulation of Zn in the MT fraction of the perfused rat liver. The present experiment confirms that MT synthesis and degradation are somewhat regulated by glucocorticoid hormone and epinephrine.
Animal ; Dexamethasone/pharmacology* ; Epinephrine/pharmacology* ; Female ; In Vitro ; Liver/drug effects ; Liver/metabolism* ; Metalloproteins/metabolism* ; Metallothionein/metabolism* ; Perfusion ; Rats ; Zinc/metabolism

OBJECTIVETo study the effects of nucleotides on apoptosis of thymocytes in mice.

METHODSApoptosis model in vivo was first established and 25 KM mice, 4 weeks old, were randomly divided into 5 groups. One group was control, and the others were test groups. Mice in test groups were injected with DEX (25 mg/kg) and the controls were treated with normal saline. 4, 8, 16, and 24 hours later the thymus and spleen were weighed and lymphocytes in thymus were separated. The apoptosis of lymphocytes was analyzed by using DNA electrophoresis and flow cytometry. 16 hours later lymphocytes apoptosis reached a peak and lasted 24 hours. Methods used to establish apoptosis model in vivo were: mice (4 weeks old) were injected with DEX (25 mg/kg), and thymus lymphocytes were separated 16 hours later and analyzed. The effects of nucleotides on apoptosis of mice thymocytes were investigated in experiment 2. Sixty KM mice, 20 g +/- 2g, 4 weeks old, were divided into four treatments: negative control group (NC), positive control group (PC), nucleotides-additive group 1 (NTS1) and nucleotides-additive group 2 (NTS2).

RESULTSBody weight gained in NST1 and NST2 were 3.71 g, 4.01 g respectively, significantly higher than NC (2.74 g) (P < 0.01) and in NST2 was significantly higher than in PC (2.96 g) (P < 0.01). Thymus index and spleen index were decreased significantly (P < 0.01), and no difference was found with the supplementation of nucleotides (P > 0.05). [Ca2+]i increased to 167.37 nmol/L, 191.16 nmol/L, 180.78 nmol/L in PC, NST1 and NST2 with DEX, being significantly higher than in NC (103.76 nmol/L) (P < 0.01). The percent of apoptosised thymocytes in groups were 0.31%, 11.93%, 9.82%, 11.15%, respectively. Thymus index and spleen index, cell apoptosis and [Ca2+]i were not differed significantly among PC, NTS1 and NTS2 groups.

CONCLUSIONNucleotides should have no significant effects on apoptosis of thymocytes in mice in vivo.

Animals ; Apoptosis ; drug effects ; Dexamethasone ; pharmacology ; Lymphocytes ; cytology ; Male ; Mice ; Nucleotides ; pharmacology ; Random Allocation ; Thymus Gland ; cytology