Hydrogen Sulfide Protects against Chemical Hypoxia-Induced Cytotoxicity and Inflammation in HaCaT Cells through Inhibition of ROS/NF-κB/COX-2 Pathway

Hydrogen sulfide (H2S) has been shown to protect against oxidative stress injury and inflammation in various hypoxia-induced insult models. However, it remains unknown whether H2S protects human skin keratinocytes (HaCaT cells) against chemical hypoxia-induced damage. In the current study, HaCaT cells were treated with cobalt chloride (CoCl2), a well known hypoxia mimetic agent, to establish a chemical hypoxia-induced cell injury model. Our findings showed that pretreatment of HaCaT cells with NaHS (a donor of H2S) for 30 min before exposure to CoCl2 for 24 h significantly attenuated CoCl2-induced injuries and inflammatory responses, evidenced by increases in cell viability and GSH level and decreases in ROS generation and secretions of IL-1β, IL-6 and IL-8. In addition, pretreatment with NaHS markedly reduced CoCl2-induced COX-2 overexpression and PGE2 secretion as well as intranuclear NF-κB p65 subunit accumulation (the central step of NF-κB activation). Similar to the protective effect of H2S, both NS-398 (a selective COX-2 inhibitor) and PDTC (a selective NF-κB inhibitor) depressed not only CoCl2-induced cytotoxicity, but also the secretions of IL-1β, IL-6 and IL-8. Importantly, PDTC obviously attenuated overexpression of COX-2 induced by CoCl2. Notably, NAC, a ROS scavenger, conferred a similar protective effect of H2S against CoCl2-induced insults and inflammatory responses. Taken together, the findings of the present study have demonstrated for the first time that H2S protects HaCaT cells against CoCl2-induced injuries and inflammatory responses through inhibition of ROS-activated NF-κB/COX-2 pathway

Case Studies Evaluating Transdermal Continuous Oxygen for the Treatment of Chronic Sickle Cell Ulcers

Objective: Refractory leg ulcerations are common in homozygous sickle cell anemia. In this case series, patients were treated with transdermal continuous oxygen therapy (TCOT), based on the hypothesis that oxygen deprivation caused by arteriovenous shunting may be remedied by providing oxygen directly to the wound bed. The authors believe this is the first attempt to treat sickle cell ulcers with TCOT. Case Presentation: Five patients with long histories of recurring sickle cell disease ulcers that would not heal with various conventional and/or other adjunctive wound healing modalities were treated with TCOT. The patients had recurring nonhealing wounds for 30, 21, 20, 20, and 15 years, respectively. All 5 patients healed or showed substantial improvement in the treatment periods of 3 to 36 weeks. Conclusion: The authors conclude that TCOT may be a novel, effective, and inexpensive modality in treating patients with sickle cell disease ulcers. Improvement was typically noticeable within 2 weeks. Further clinical trials may be considered to evaluate the efficacy of TCOT in sickle cell ulcers

Ozone Treatment of Alveolar Bone in the Cape Chacma Baboon Does Not Enhance Healing Following Trauma

In the international literature, the role of Ozone (O3) in the advancement in alveolar bone healing in the absence of bone pathology was not tested before. The purpose of this study was to evaluate alveolar bone regeneration after a bone defect was created and treated with a single topical administration of O3. Alveolar bone defects were created on five healthy chacma baboons. One side of the maxilla and mandible was topically treated with a single treatment of an O3/O2 mixture (3,5–4 % O3), while the opposite sides were not treated and thus served as control. Regeneration was measured radiologically, using a standardized gray scale, as the increase in bone density in the treatment area at 3 and 6 weeks post-operative and was statistically analyzed using multivariate analysis of variance (MANOVA). There were no significant differences in densities observed between the O3/O2 mixture treatment and the control (p[0.05). A single O3 treatment did not increase alveolar bone healing over a 3- and 6-week period in the mandible and the maxilla.Dental Research Education & Development Trust of the South African Dental Associationhttp://link.springer.com/journal/12663hb2014ay201