Objective: To investigate the effect of permeable resin on the surface structure, microhardness and color of tooth enamel after bleaching. Methods: Premolars extracted for orthodontic needs were selected (provided by the Department of Oral and Maxillofacial surgery of the first affiliated Hospital of Zhengzhou University) and randomly divided into A, B and C 3 groups. Each group was randomly divided into control subgroup, resin subgroup, bleaching subgroup and combined subgroup. Samples in the control subgroup did not receive any treatment. Those in the bleaching subgroup and combined subgroup were treated with cold light whitening. Those in the resin group and combined group were treated with permeable resin. Samples in the group A were observed by scanning electron microscope immediately after treatment and 2 weeks after treatment, and the microhardness of samples in the group B was measured before treatment, immediately after treatment and 2 weeks after treatment (the sample size of each time point was 8 in each subgroup). In group C, chromaticity was measured and chromatic aberration (ΔE value) was calculated before treatment, immediately after treatment and 1 and 2 weeks after treatment (10 samples in each subgroup). Results: Scanning electron microscope showed that the enamel surface of the resin subgroup and the combined group was smooth immediately after treatment, which was basically the same as that of the control subgroup, but covered with resin, and microporous defects and mineral deposits could be seen on the surface of the bleaching subgroup. Two weeks after treatment, the enamel surface of each subgroup was smooth, there was no obvious difference. Immediately after treatment, the microhardness of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were (354±33), (364±21), (411±30) and (350±17) HV, respectively (F=9.39,P<0.05). The microhardness of the bleaching subgroup was significantly higher than that of the other subgroups (P<0.05). There was no significant difference in microhardness among the four subgroups before treatment and 2 weeks after treatment (F=0.34, 2.75, P>0.05). Immediately after treatment, the ΔE values of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were 0.00±0.00, 2.29±1.86, 7.20±1.94 and 8.00±0.88, respectively (F=74.21,P<0.05); except that there was no significant difference between bleaching subgroup and combined subgroup (P>0.05), there were significant differences among the other subgroups (P<0.05). There was no significant difference in ΔE value among control subgroup, resin subgroup and bleaching subgroup at each time point (F=1.66, 0.30, 0.96, P>0.05). The difference in the combined subgroup immediately after treatment was significantly higher than that at 1 and 2 weeks after treatment (t=4.73, 4.23,P<0.05), but there was no significant difference between 1 and 2 weeks after treatment (t=0.75, P>0.05), and the color tended to be stable. Conclusions: When whitening healthy enamel, simple cold light whitening or cold light whitening combined with permeation resin can achieve whitening effect.
Color ; Dental Enamel ; Hardness ; Humans ; Hydrogen Peroxide/pharmacology* ; Tooth Bleaching/adverse effects* ; Tooth Bleaching Agents/pharmacology*

Hydrogen peroxide is commonly used as a disinfectant that has been reported to cause chemical colitis. We report a case of 49 year-old man who presented with chemical colitis caused by self-inflicted hydrogen peroxide enema. In the sigmoidoscopic examination, diffuse erythematous and edematous mucosal change with multiple ulcerations and easy touch bleeding was noted from the rectum to the proximal sigmoid colon. Abdominal computed tomography showed diffuse wall thickening of the rectum and the sigmoid colon with inflammatory and reactive change at surrounding. The patient was treated with NPO, intravenous fluid, and antibiotic therapy. On 5th hospital day, abdominal pain and bloody stool disappeared, and the patient started oral feeding. He discharged on 6th hospital day with fully recovered state.
Abdominal Pain/etiology ; Colitis/*chemically induced/therapy ; Enema/*adverse effects ; Gastrointestinal Hemorrhage/etiology ; Humans ; Hydrogen Peroxide/*adverse effects ; Male ; Middle Aged ; Sigmoidoscopy ; Tomography, X-Ray Computed

AIMTo examine the effect of HO-1 inducer hemin on hydrogen peroxide (H2O2) caused decrease in contraction of isolated rat aortic rings, and to elucidate the underlying mechanism.

METHODSThe thoracic aortic rings with endothelium of male Sprague-Dawley rats were mounted on a bath system. Isometric contractions of aortic rings were measured.

RESULTS(1) After intraperitoneal injection of HO-1 inducer hemin, HO-1 activity of thoracic aorta and COHb concentration in rat blood enhanced. And it also prevented the decrease in contraction responses to PE which pretreatment of arteries with 300 micromol/L H2O2. (2) Pretreatment of ATP-sensitive potassium channel inhibitor glibenclamide, but not GC inhibitor methylene blue, could partly abolish the protection of hemin in arteries with H2O2 exposure. (3) Hemin could not influence the shift of concentration-response curve to [Ca2+]o in arteries with H2O2 exposure. (4) In Ca(2+) -free K-H solution, exposure of H2O2 reduced caffeine and PE-induced constriction in the rat aortic rings. After pretreatment of hemin, could prevent the decrease in contraction responses to caffeine and PE.

CONCLUSIONIncrease in HO-1 activity could prevent the H2O2 induced decrease in contraction responses to PE in intact aortic rings. The mechanism might be involved in activation of ATP-sensitive potassium channel and mobilization of intracellular calcium stores, but had no relationship with the GC pathway.

Animals ; Aorta, Thoracic ; drug effects ; physiology ; Endothelium, Vascular ; Heme Oxygenase-1 ; pharmacology ; Hydrogen Peroxide ; adverse effects ; KATP Channels ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Vasoconstriction ; drug effects

OBJECTIVETo study the effects of ecdysterone (ECR) on the expression of nuclear factor (NF)-kappaB in H2O2 induced oxidative damage of human lens epithelial cells (HLECs).

METHODSThe cultured HLECs were divided into 5 groups, i.e., the control group, the H2O2 group, the beta-estradiol (E2) group, the ECR group, and the pyrrolidine dithiocarbamate group (PDTC) group. The expression rate of NF-kappaB p65 in the HLECs were detected by flow cytometer (FCM).

RESULTSThe expression of NF-kappaB p65 occurred in normal HLECs (9. 53%). The expression rate of NF-kappaB p65 in the H2O2 group obviously increased (39.87%, P < 0.01). The expression rate of NF-kappaB p65 in the PDTC group obviously decreased (5.90%, P < 0.01). The expression rates of NF-kappaB p65 in the ECR group (13.99%) and the E2 group (25.18%) ranged between the control group and the H2O2 group, but still lower than that of the H2O2 group (P < 0.01).

CONCLUSIONSThe activation of NF-kappaB in the HLECs could be induced by H2O2 ECR with the estrogenic activity could effectively inhibit the activation of NF-kappaB.

Cells, Cultured ; Ecdysterone ; pharmacology ; Epithelial Cells ; drug effects ; metabolism ; Humans ; Hydrogen Peroxide ; adverse effects ; Lens, Crystalline ; cytology ; Oxidative Stress ; drug effects ; Transcription Factor RelA ; metabolism

OBJECTIVETo analyze the mechanisms of NAC on endoplasmic reticulum (ER) stress mediated cells apoptosis of HepG2 cells and to evaluate the potential role of NAC in the treatment of liver injury.

METHODSHepG2 cells were treated with H2O2 to make a model of oxidative ER stress mediated apoptosis. To evaluate the apoptosis, various methods such as MTT, DNA ladder, Western blot and flow cytometry were used. Then the optimal dosage and incubation time of NAC intervention in apoptosis were ascertained, and the differences between induction and intervention of apoptosis, including the percentage of apoptosis, the expression of apoptotic protein (GRP78, Caspase-12, PARP) and the production of reactive oxygen species (ROS) were compared.

RESULTSThe activity of the cells decreased by H2O2 (0, 1, 3, 5 mmol/L) treatments in a dose-dependent manner. The ratio of apoptotic cells increased (0.7%+/-0.5%, 26.4%+/-1.8%, 29.7%+/-1.2% and 51.2%+/-9.4%, respectively) as did the production of ROS (14.0%+/-0.5%, 95.2%+/-0.1%, 97.5%+/-0.2% and 98.3%+/-0.2%, respectively). The HepG2 cells showed typical morphologic change of ER stress 6 hr after they were treated with 3 mmol/L H2O2. ER stress mediated-apoptosis was confirmed by Western blot. NAC (10 mmol/L and 20 mmol/L) protected cells from apoptosis. Typical features of ER stress apoptosis were seen accompanied by diminishing the ratio of apoptotic cells from 29.7%+/-1.2% to 23.3%+/-4.7% and 14.3%+/-1.2%. The production of ROS also decreased from 97.5%+/-0.2% to 52.2%+/-0.8% and 51.2%+/-2.9%. The effect was related to the concentration: 20 mmol/L NAC was more effective than 10 mmol/L.

CONCLUSIONSAs an oxidizing agent, H2O2 may induce ROS in cells and induce oxidative stress, causing ER stress and apoptosis. NAC can inhibit the procession of ROS directly and prevent injuries to the hepatocytes.

Acetylcysteine ; pharmacology ; Apoptosis ; drug effects ; Endoplasmic Reticulum ; metabolism ; Hep G2 Cells ; Humans ; Hydrogen Peroxide ; Oxidative Stress ; Reactive Oxygen Species ; adverse effects

OBJECTIVETo study the effects of Guanxinping Tablet (GT) containing serum on H2O2-induced apoptosis and the nuclear factor kappa B (NF-kappaB) expression in vascular endothelial cells (VECs).

METHODSRabbits were randomly divided into the normal control group (treated with normal saline, 10 mL/kg), the verapamil group (0. 02 g/kg, 10 mL/kg), the small dose GT group (2; 8 g/kg, 10 mL/kg), the middle dose GT group (5.6 g/kg, 10 mL/kg), and the large dose GT group (11.2 g/kg, 10 mL/kg), 3 in each group. The medication was given to rabbits by gastrogavage for 3 successive days. The gastrogavage was performed twice on the last day with an interval of 2 h. One h after the last medication the peripheral blood was sampled from the vein of the ear edge. The blood was put for 1 h and centrifuged at 2 500 r/min for 30 min. The serum was extracted and deactivated at 56 degrees C for 30 min to prepare the drug containing serum. The apoptosis injury model was established using 100 micromol/L H2O2 induced VECs in the log phase growth. After modeling they were divided into 6 groups, 5 samples in each group, i. e., the normal group (10% vehicle serum culture solution), the model group (10% vehicle serum culture solution +100 micromol/L H2O2), the verapamil group (10% verapamil serum culture solution +100 micromol/L H2O2), the low dose GT group (10% low dose GT culture solution +100 micromol/L H2O2), the middle dose GT group (10% middle dose GT culture solution + 100 micromol/L H2O2), and the high dose GT group (10% high dose GT culture solution + 100 micromol/L H2O2). THE VEC apoptotic rate was detected using flow cytometry. The protein expression of NF-kappaB was detected using Western blot.

RESULTSThe VEC apoptosis rate (9.00% +/- 1.18%) and the protein expression of NF-kappaB (0.39% +/- 0.06%) increased more in the model group than in the normal control group (P<0.01). Compared with the model group, the VEC apoptosis rate of the verapamil group (6.00% +/- 0.18%), the large dose GT group (5.30% +/- 0.08%), and the middle dose GT group (6.83% +/- 0.51%) were obviously lower. The expression of NF-kappaB of each treatment group significantly decreased (the verapamil group: 0.28% +/- 0.03%; the small dose GT group: 0.33% +/- 0.03%; the middle dose GT group: 0.30% +/- 0.03%; the large dose GT group: 0.28% +/- 0.04%, P<0.01, P<0.05).

CONCLUSIONSGT could fight against H2O2-induced VEC cell apoptosis. Its mechanism might be correlated with regulating the expression of NF-kappaB protein.

Animals ; Apoptosis ; drug effects ; Cells, Cultured ; Drugs, Chinese Herbal ; pharmacology ; Endothelial Cells ; cytology ; metabolism ; Humans ; Hydrogen Peroxide ; adverse effects ; Male ; NF-kappa B ; metabolism ; Rabbits ; Serum

Recently, it has been reported that curcumin, which is known as a potent antioxidant, acts as a non-stressful and non-cytotoxic inducer of the cytoprotective heme oxygenase (HO)-1. In this study, naturally occurring curcuminoids, such as pure curcumin, demethoxycurcumin (DMC) and bis-demethoxycurcumin (BDMC), were compared for their potential ability to modulate HO-1 expression and cytoprotective activity in human endothelial cells. All three curcuminoids could induce HO-1 expression and HO activity with differential levels. The rank order of HO activity was curcumin, DMC and BDMC. In comparison with endothelial protection against H2O2-induced cellular injury, cytoprotective capacity was found to be highest with curcumin, followed by DMC and BDMC. Interestingly, cytoprotective effects afforded by curcuminoids were considerably associated with their abilities to enhance HO activity. Considering that the main difference among the three curcuminoids is the number of methoxy groups (none for BDMC, one for DMC, and two for curcumin), the presence of methoxy groups in the ortho position on the aromatic ring was suggested to be essential to enhance HO-1 expression and cytoprotection in human endothelial cells. Our results may be useful in designing more efficacious HO-1 inducers which could be considered as promising pharmacological agents in the development of therapeutic approaches for the prevention or treatment of endothelial diseases caused by oxidative damages.
Signal Transduction ; Models, Biological ; Hydrogen Peroxide/adverse effects ; Humans ; Heme Oxygenase-1/*metabolism/physiology ; Endothelial Cells/*drug effects/*metabolism ; DNA Damage/drug effects ; Cytoprotection/*drug effects ; Curcumin/*analogs & derivatives/*pharmacology

OBJECTIVETo investigate the role of Fas pathway in H(2)O(2)-induced apoptosis of L02 human hepatocytes and the effect of schisandrin B on Fas pathway.

METHODSReal-time quantitative PCR was used to detect the expressions of FAS, fas associated death domain protein (FADD) and caspase-8 mRNA in L02 cells exposed to H(2)O(2). Flow cytometry was employed to assess the cell apoptosis. ELISA, Western blotting and spectrophotometric assay were performed to determine the expressions of FAS protein, FADD protein and caspase-8 activity.

RESULTSWithin the dose range of 5-15 mol/L, schisandrin B dose-dependently inhibited FAS and FADD expressions and caspase-8 activation.

CONCLUSIONSchisandrin B can partially inhibit H(2)O(2)-induced L02 cell apoptosis possibly by affecting the FAS-FADD-caspase-8 pathway.

Apoptosis ; drug effects ; Caspase 8 ; metabolism ; Cell Line ; Cyclooctanes ; pharmacology ; Fas-Associated Death Domain Protein ; metabolism ; Flow Cytometry ; Hepatocytes ; drug effects ; metabolism ; Humans ; Hydrogen Peroxide ; adverse effects ; Lignans ; pharmacology ; Polycyclic Compounds ; pharmacology ; Signal Transduction ; fas Receptor ; metabolism

The aim of this study was to explore the protective effect of compound tianpupian (TPP) against (2)O(2)-induced the apoptosis of murine splenic lymphocytes and its mechanism. The cell apoptosis rate was detected by MTT method; the cell apoptosis and mitochondrial membrance potential were detected by flow cytometry (FCM) with Annexi-V/PI double staining and JC-1 staining method, respectively; and caspase 3 relative activity was determined by colorimetry. The results indicated that after treating with (2)O(2), the absorbance value of cultured lymphocytes and the red/green ratio of JC-1 were reduced, and the apoptotic rate and caspase 3 activity were increased, coculture of (2)O(2)-treated cells with compound TPP increased the cell absorbance ratio and red/green rate of JC-1, while reduced the apoptosis rate and caspase 3 activity. It is concluded that compound TPP alleviates intracellular oxidative damages and dose-dependently inhibited apoptosis of murine splenic lymphocytes through reducing mitochondrial membrane potential and inhibiting caspase 3 activity. This suggests that compound TPP is a potential anti-apoptotic agent.
Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Drugs, Chinese Herbal ; pharmacology ; Grape Seed Extract ; pharmacology ; Hydrogen Peroxide ; adverse effects ; Lymphocyte Count ; Lymphocytes ; cytology ; drug effects ; Mice ; Mice, Inbred ICR ; Proanthocyanidins ; pharmacology ; Rhodiola

BACKGROUNDCigarette smoke induced airway inflammation plays a role in pathogenesis of airway inflammation. Resolvin-D1 derived from omega-3 polyunsaturated fatty acids is an endogenous anti-inflammatory and proresolving lipid mediator. Resolvin-D1 ameliorated inflammatory responses in lung injury, asthma, peritonitis and atherosclerosis. We investigated whether resolvin-D1 suppressed the productions of chemokines and oxidative stress induced by cigarette smoke extract (CSE) in vitro and its possible mechanism.

METHODSWe examined the proinflammatory chemokine interleukin-8 and hydrogen peroxide (H2O2) productions induced by CSE in 16 human bronchial epithelial (16HBE) cells after resolvin-D1 treatment and their mechanisms. 16HBE cells were treated with resolvin-D1 at up to 10 nmol/L, for 30 minutes before CSE up to 16% (v/v) exposure. Release of interlukin-8 proteins was assessed by enzyme linked immunosort assay (ELISA) and its mRNA level by RT-PCR. We evaluated extracellular H2O2 expression in the supernatant. Phosphorylation of NF-κB/p65 and degradation of I-κB in 16HBE cells were determined by Western blotting analysis and NF-κB DNA binding activity by electrophoretic mobility shift assay (EMSA).

RESULTS16HBE cells treated with 8% CSE showed significantly higher interlukin-8 production. Resolvin-D1 pretreatment inhibited CSE induced interlukin-8 production (mRNA and protein) in a dose and time dependent manner. Extracellular H2O2 level decreased after resolvin-D1 treatment. Resolvin-D1 attenuated CSE triggered I-κB degradation and NF-κB/p65 activation dose dependently and inhibited NF-κB DNA binding activity.

CONCLUSIONResolvin-D1 inhibits CSE induced interlukin-8 and H2O2 production in 16HBE cells by modulating NF-κB activation and has therapeutic potential for pulmonary inflammation.

Blotting, Western ; Cell Line ; Cell Survival ; drug effects ; Docosahexaenoic Acids ; pharmacology ; Electrophoretic Mobility Shift Assay ; Enzyme-Linked Immunosorbent Assay ; Humans ; Hydrogen Peroxide ; metabolism ; Interleukin-8 ; metabolism ; NF-kappa B ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Smoking ; adverse effects