ABSTRACT
Although favorable immune responses to low-dose irradiation (LDI) have been observed in normal mice, i.e., a hormesis effect, little is known about the effects of LDI in infectious diseases. In this study, we examined the effects of LDI on mice with sepsis, a severe and often lethal hyperinflammatory response to bacteria. Female C57BL/6 mice were whole-body irradiated with 10cGy 48h before Escherichia coli infection, and survival, bacterial clearance, cytokines, and antioxidants were quantified. LDI pretreatment significantly increased survival from 46.7% in control mice to 75% in mice with sepsis. The bacterial burden was significantly lower in the blood, spleen, and kidney of LDI-treated mice than in those of control septic mice. The levels of pro-inflammatory cytokines, e.g., IL-1ß and IL-6, as well as anti-inflammatory IL-10 were markedly reduced in pre-LDI septic mice. Nitric oxide production by peritoneal macrophages was also reduced in pre-LDI septic mice. Immune cells in the spleen increased and Nrf2 and HO-1 were induced in pre-LDI septic mice. LDI stimulates the immune response and minimizes lethality in septic mice via enhanced bacterial clearance and reduced initial proinflammatory responses.
Subject(s)
Escherichia coli Infections/radiotherapy , Sepsis/radiotherapy , Whole-Body Irradiation , Animals , Colony Count, Microbial , Cytokines/blood , Escherichia coli/isolation & purification , Escherichia coli Infections/blood , Escherichia coli Infections/immunology , Escherichia coli Infections/microbiology , Female , Kidney/microbiology , Kidney/radiation effects , Macrophages, Peritoneal/metabolism , Macrophages, Peritoneal/radiation effects , Mice , Mice, Inbred C57BL , Nitric Oxide/metabolism , RAW 264.7 Cells , Sepsis/blood , Sepsis/immunology , Sepsis/microbiology , Spleen/microbiology , Spleen/radiation effectsABSTRACT
BACKGROUND AND OBJECTIVES: Unique properties of carbon nanotubes (CNTs) would open new avenues for addressing challenges to realize rapid and sensitive antimicrobial diagnostics and therapy for human pathogens. In this study, new CNTs' capabilities for photothermal (PT) antimicrobial nanotherapy were explored in vitro using Escherichia coli as a model bacterium. STUDY DESIGN/MATERIALS AND METHODS: Single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) were incubated with E. coli K12 strain. CNTs' locations in bacteria and laser-induced thermal and accompanied effects around CNTs were estimated with TEM and PT microscopy, respectively. Multi-pulse lasers at 532 and 1064 nm with 12-ns pulse duration were used for irradiating sample mixtures at different laser fluences. Cell viability was evaluated using a bacterial viability test kit and epi-fluorescence microscopy. RESULTS: This study revealed CNTs' high binding affinity to bacteria, their capability to self-assemble as clusters at bacteria surfaces, and their inherent near-infrared (NIR) laser responsiveness. Cell viability was affected neither by CNTs alone nor by NIR irradiations alone. Notable changes in bacteria viability, caused by local thermal and accompanied bubble-formation phenomena, were observed starting at laser fluences of 0.1-0.5 J/cm(2) with complete bacteria disintegration at 2-3 J/cm(2) at both wavelengths. Furthermore, ethanol in reaction mixtures significantly (more than one order) enhanced bubble formation phenomena. CONCLUSION: This first application of laser-activated CNTs as PT contrast antimicrobial agents demonstrated its great potential to cause irreparable damages to disease-causing pathogens as well as to detect the pathogens at single bacterium level. This unique integration of laser and nanotechnology may also be used for drinking water treatment, food processing, disinfection of medical instrumentation, and purification of grafts and implants. Furthermore, the significant ethanol-induced enhancement of bubble formation provides another unique possibility to improve the efficiency of selective nanophotothermolysis for treating cancers, wounds, and vascular legions.
Subject(s)
Escherichia coli Infections/diagnosis , Escherichia coli Infections/radiotherapy , Escherichia coli/growth & development , Nanotechnology/methods , Nanotubes, Carbon , Phototherapy/methods , Escherichia coli/radiation effects , Escherichia coli Infections/microbiology , Humans , Microscopy, Electron, Transmission , Microscopy, Fluorescence , Reproducibility of ResultsABSTRACT
Treatment with L-asparaginase and low-frequency laser decreased adhesion of uropathogenic Escherichia coli to human erythrocytes. The maximum effect was observed after combined treatment (laser exposure followed by enzyme treatment).
Subject(s)
Asparaginase/therapeutic use , Escherichia coli/drug effects , Escherichia coli/radiation effects , Laser Therapy , Urinary Tract Infections/microbiology , Bacterial Adhesion/drug effects , Bacterial Adhesion/radiation effects , Combined Modality Therapy , Erythrocytes/drug effects , Erythrocytes/radiation effects , Escherichia coli/isolation & purification , Escherichia coli Infections/drug therapy , Escherichia coli Infections/microbiology , Escherichia coli Infections/radiotherapy , HumansABSTRACT
An investigation is made of the effect of low-intensity millimeter waves on the development of acute and chronic pyelonephritis. It is shown that the application of millimeter waves diminishes the rate of pyelonephritis recurrence and reduces the probability of chronic pyelonephritis. Furthermore, these waves normalize lipid peroxidation, stimulate antioxidant protection, and improve blood rheology. Experimental investigations performed on animals provided evidence for the positive effect of millimeter waves on the morphofunctional state of organs and tissues as well as on blood circulation. This especially concerns pyelonephritis of mycoplasmic etiology.
