H2O2 enhances the spontaneous phasic contractions of isolated human-bladder strips via activation of TRPA1 channels on sensory nerves and the release of substance P and PGE2.

Several studies have indicated that reactive oxygen species (ROS) can lead to detrusor overactivity (DO), but the underlying mechanisms are not known. Hydrogen dioxide (H2O2) is used commonly to investigate the effects of ROS. In present study, we investigated the effects of H2O2 on phasic spontaneous bladder contractions (SBCs) of isolated human-bladder strips (iHBSs) and the underlying mechanisms. Samples of bladder tissue were obtained from 26 patients undergoing cystectomy owing to bladder cancer. SBCs of iHBSs were recorded in organ-bath experiments. H2O2 (1µM-10mM) concentration-dependently increased the SBCs of iHBSs. These enhancing effects could be mimicked by an agonist of transient receptor potential (TRP)A1 channels (allyl isothiocyanate) and blocked with an antagonist of TRPA1 channels (HC030031; 10 µM). H2O2 induced enhancing effects also could be attenuated by desensitizing sensory afferents with capsaicin (10 µM), blocking nerve firing with TTX (1 µM), blocking neurokinin effects with NK2 receptor antagonist (SR48968, 10 µM), and blocking PGE2 synthesis with indomethacin (10 µM), respectively. Our study: (i) suggests activation of TRPA1 channels on bladder sensory afferents, and then release of substance P or PGE2 from sensory nerve terminals, contribute to the H2O2-induced enhancing effects on SBCs of iHBSs; (ii) provides insights for the mechanisms underlying ROS leading to DO; (iii) indicates that targeting TRPA1 channels might be the promising strategy against overactive bladder in conditions associated with excessive production of ROS.

H2O2 participates in ABA regulation of grafting-induced chilling tolerance in cucumber.

KEY MESSAGE: Rootstock provides more abscisic acid (ABA) content to scions to increase the chilling tolerance of seedlings. H2O2 is involved in ABA regulation of grafting-induced chilling tolerance of cucumber. Here we examined the role of ABA in the response of grafted cucumber to chilling stress. The data showed chilling induced an increase in leaf and root ABA content and there was a positive correlation between ABA content and the chilling tolerance of the varieties. The increase of ABA content and NCED mRNA abundance in the leaf of both Cs/Cs (self-root) and Cs/Cm (grafted with pumpkin as rootstock) showed a delay under aerial stress compared with those under whole plant and root-zone stress. Intriguingly, an increase in ABA in xylem was found under whole-plant and root-zone chilling stress but was not detected under aerial stress, implying the increases in ABA content in leaves were mainly from root ABA transportation. Compared to Cs/Cs, a higher ABA content and NCED mRNA abundance were observed in Cs/Cm, which showed that Cm could output more ABA than Cs. The removal of endogenous ABA decreased the difference in chilling tolerance induced by Cm, as evidenced by the observed similar oxidative stress levels and photosynthetic capacity between Cs/Cs and Cs/Cm after chilling stress. Moreover, we found that the H2O2 signal in grafted cucumber could respond to chilling stress earlier than the H2O2 signal in self-rooted cucumber. The inhibition of endogenous H2O2 decreased the chilling tolerance of grafted cucumber induced by ABA by reducing photosynthesis and the mRNA abundance of CBF1 and COR. Thus, our results indicate that H2O2, as the downstream signal, participated in the rootstock-induced chilling tolerance of grafted seedlings induced by ABA.

Effect of Hydrogen Dioxide Treatment on the Osteogenic Potential of Duck-beak Bone-derived Natural Bioceramic Microparticles.

BACKGROUND/AIM: As an alternative material to the autogenous bone, duck-beak bone particle for bone substitute have been attracting great attention due to their biological properties. To deliver the most favorable outcome of medical treatment, it is essential to study the effect of various processing methods of the duck-beak bone. In this study, we compared the two deproteinizing agents for manufacturing duck-beak bone. Group 1 was treated by a conventional chemical agent (ethylenediamine) and Group 2 by hydrogen dioxide (H2O2). In vitro and in vivo experiments were conducted in parallel to compare the cytocompatibility and osteogenic capability between two processing methods. For in vitro tests, human adipose-derived mesenchymal stem cells (hAD-MSCs) were planted onto each sample and their attachment and growing were evaluated. For in vivo biocompatibility and osteogenic properties, the samples were applied on the critical-sized calvarial bone defect of rats. Group 2 showed significantly higher cell attachment but Group1 showed slightly higher cell proliferation. In in vivo tests, all groups have shown biocompatibility and increased level of osteogenic potential. However, Group 2 had significantly higher bone regeneration (p<0.05). This experiment confirmed that H2O2 can be an optimal processing method for duck-beak bone particle.

Different effects of H2O2 treatment on cervical squamous carcinoma cells and adenocarcinoma cells.

INTRODUCTION: This study aims to compare the antioxidant abilities of cervical squamous carcinoma cells and cervical adenocarcinoma cells and to study the related mechanisms. MATERIAL AND METHODS: Cervical squamous carcinoma and adenocarcinoma cells were treated with H2O2. Cell proliferation was determined with the MTT assay. The reactive oxygen species (ROS) level was detected by the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) method. The 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) method was performed to measure intracellular concentrations of reduced glutathione (GSH) and oxidized glutathione (GSSG). The nitrite formation method, the molybdate colorimetric method, and the DTNB colorimetric method were used to determine activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), respectively. RESULTS: Compared with untreated control cells, cell proliferation of cervical squamous carcinoma cells and cervical adenocarcinoma cells was significantly inhibited by H2O2 treatment (p < 0.05). Reactive oxygen species levels and GSSG levels were significantly increased (p < 0.01), whereas GSH levels were significantly decreased (p < 0.05 or 0.01) in both cells after H2O2 treatment. Thus the ratio of GSH/GSSG was significantly decreased by H2O2 treatment in both cells (p < 0.01). In addition, H2O2 treatment significantly increased activities of SOD, CAT, and GPx in both cells (p < 0.05 or 0.01). Furthermore, the above-mentioned changes induced by H2O2 treatment were more dramatic in cervical squamous carcinoma cells. CONCLUSIONS: The antioxidant ability of cervical squamous carcinoma cells is lower than that of cervical adenocarcinoma cells, which may be related to the increased ROS levels in cervical squamous carcinoma cells induced by H2O2 treatments.

Study on Technique of Control and Monitor System of Hydrogen Dioxide Plasma Sterilizer / 医疗卫生装备

Objective To develop a facility to sterilize the heat-sensitive precise medical surgical instruments which can not resist high temperature and high pressure. Methods We used electromagnetic field of high frequency as excitation source for plasma,vacuumized the instrument,pumped in the peroxide,maintained the pressure in the instrument within a certain range,and then applied magnetic RF electric field,causing glow discharge and generating ambiplasma. The microorganism could be quickly destroyed under the synergistic effect of peroxide and low -temperature ambiplasma. Results The facility can sterilize the medical instruments within 45 minutes,enhance the surgical security and reduce the cost. Conclusion By controlling the primary parameters such as temperature,vacuity and time,the sterilization process can be finished in a low temperature safely,easily and quickly,so it is gradually accepted by the medical department.

Inhibition of probucol on the apoptosis of vascular smooth muscle cell induced by hydrogen peroxide / 中国药理学通报

Aim To investigate the effects of antioxidant probucol on vascular smooth muscle cells(VSMCs) apoptosis induced by H2O2.Methods H2O2 (1 mmol?L-1) was used to induce VSMCs apoptosis.The VSMCs were treated with probucol(100,10,1 ?mol?L-1) for 6 hours.For the evaluation of apoptosis,Annexin V-FITC staining,Hoechest33258 staining and the TUNEL assay were used.The expressions of ASK-1 and Trx-1 were detected by Western blot analysis.Results H2O2 could promote the apoptosis of VSMCs,increase the expression of ASK-1 and decrease the expression of Trx-1.Probucol could attenuate the apoptosis induced by H2O2 in a dose-dependent,down-regulate ASK-1 expression and increase Trx-1 expression.Conclusion Probucol can antagonize the apoptosis of VSMCs induced by H2O2.The mechanism may be correlated with a decreased expression of ASK-1 and an increased expression of Trx-1.