AIMTo investigate the survival rate and the level of HaCaT cells damage with ultraviolet B (UVB) radiation at various doses, and observe the protective effects of ginsenoside Rg1 and Rb1 in vitro.

METHODSMTT assay was employed to analyze the cell survival rate after UVB radiation of 30, 60, 90 and 120 mJ x cm(-2). The damage of nucleolus and the protective effects of ginsenoside Rg1 and Rb1 were scanned by Hoechst 33258 staining and single cell gel electrophoresis assay (SCGE).

RESULTSIt was found that the cell survival rate decreased gradually and the damage of nucleolus aggravated as the radiation dose increased from 30 mJ x cm(-2) to 120 mJ x cm(-2). At the dose of 20 microg x mL(1-), obvious protective effect of ginsenoside Rg1 and Rb1 can be observed against UVB radiation-induced HaCaT cells growth inhibition and nucleolus damage.

CONCLUSIONUVB radiation inhibits HaCaT human keratinocytes growth and ginsenoside Rg1 and Rb1 can relief the damage.

Apoptosis ; drug effects ; radiation effects ; Cell Line ; Cell Survival ; drug effects ; radiation effects ; DNA Damage ; drug effects ; radiation effects ; Dose-Response Relationship, Radiation ; Ginsenosides ; isolation & purification ; pharmacology ; Humans ; Keratinocytes ; cytology ; drug effects ; radiation effects ; Panax ; chemistry ; Plants, Medicinal ; chemistry ; Protective Agents ; isolation & purification ; pharmacology ; Ultraviolet Rays ; adverse effects

Equol, an isoflavonoid metabolite produced from the dietary isoflavone daidzein by the gut microflora in mammals, has been found to protect not only against ultraviolet (UV) radiation-induced cutaneous inflammation and photoimmune suppression, but also have antiphotocarcinogenic properties in mice. Because the state of DNA damage has been correlated with suppression of the immune system and photocarcinogenesis, we have therefore examined the potential of equol to offer protection from solar-simulated UV (SSUV) radiation-induced DNA damage in hairless mice by the immunohistochemical approach using monoclonal antibody specific for cyclobutane pyrimidine dimers (CPDs; H3 antibody). Topical application of 20 micrometer equol lotion, which was applied both before and after SSUV significantly reduced the number of CPDs. This reduction was evident immediately after SSUV exposure, at 1 h after exposure, and at 24 h after exposure, revealing 54%, 50%, and 26% reduction in CPDs, respectively. When the same concentration was applied for 5 consecutive days after SSUV exposure, there was no significant difference in the reduction of CPDs immediately after SSUV irradiation or at 1 hour afterwards, but there were significant reductions of 23% and 42% at 24 and 48 h after SSUV exposure, respectively. Despite apparently reducing the number of CPDs post-SSUV, topically applied equol did not appear to increase the rate of dimer removal. To conclude, equol applied topically prior to SSUV irradiation offers protection against CPD formation in hairless mice, possibly by acting as a suncreen and thus inhibiting DNA photodamage.
Administration, Topical ; Animals ; DNA/drug effects/radiation effects ; *DNA Damage ; Female ; Immunohistochemistry ; Isoflavones/*pharmacology ; Mice ; Mice, Inbred HRS ; Pyrimidine Dimers/metabolism ; Skin/drug effects/metabolism/*radiation effects ; Sunlight/adverse effects ; Ultraviolet Rays/*adverse effects

AIM: Radiation induces an important apoptosis response in irradiated organs. The objective of this study was to investigate the radioprotective effect of tetramethylpyrazine (TMP) on irradiated lymphocytes and discover the possible mechanism of protection. METHOD: Lymphocytes were pretreated for 12 h with TMP (25-200 μmol·L(-1)) and then exposed to 4 Gy radiation. Cell apoptosis and the signaling pathway were analyzed. RESULTS: Irradiation increased cell death, DNA fragmentation, activated caspase activation and cytochrome c translocation, downregulated B-cell lymphoma 2 (Bcl-2) and up-regulated Bcl-2-associated X protein (Bax). Pretreated with TMP significantly reversed this tendency. Several anti-apoptotic characteristics of TMP, including the ability to increase cell viability, inhibit caspase-9 activation, and upregulate Bcl-2 and down-regulate Bax in 4Gy-irradiated lymphocytes were determined. Signal pathway analysis showed TMP could translate nuclear factor-κB (NF-κB) from cytosol into the nucleus. CONCLUSION The results suggest that TMP had a radioprotective effect through the NF-κB pathway to inhibit apoptosis, and it may be an effective candidate for treating radiation diseases associated with cell apoptosis.
Apoptosis ; drug effects ; radiation effects ; Cell Line ; Cell Survival ; drug effects ; radiation effects ; DNA Fragmentation ; drug effects ; radiation effects ; Drugs, Chinese Herbal ; pharmacology ; Humans ; Lymphocytes ; cytology ; drug effects ; radiation effects ; NF-kappa B ; genetics ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Pyrazines ; pharmacology ; Radiation-Protective Agents ; pharmacology ; bcl-2-Associated X Protein ; genetics ; metabolism

OBJECTIVETo evaluate the value of the "comet" assay in detecting the radiosensitivity in human tumor cell lines.

METHODSThe radiation-induced primary DNA damage and repair were detected by the comet assay in CNE-1 and 973 cell lines. The tail moment was used as the end point, to quantitate the primary DNA damage and subsequent repair ability. The cell-survival curve was plotted by the classical colony assay, to detect the D(0) value and Dq value. The results from the above two assays were compared.

RESULTS1. With the increment of irradiation doses, under the same experimental condition, the radiation-induced primary DNA damage was more severe in CNE-1 cells than in 973 cells (P < 0.01). From the cell-survival curves, the D(0) value was 1.631 and 1.822 in CNE-1 and CNE-1 973 cells respectively, indicating that CNE-1 cells were more sensitive to irradiation than 973 cells. The radiosensitivity detected by comet assay and by colony assay in the two cell lines tended to be consistent. 2. The half-repair time of 973 and CNE-1 cell line was 33 min and 41 min detected by comet assay, which indicats that the ability of DNA damage and repair in CNE-1 cells was weaker than in 973 cells. The Dq value of the cell survival curve was 2.152 for 973 and 0.626 for CNE-1 cell line detected by the colony assay, which indicates that the sublethal damage repair in 973 cells being much faster than in CNE-1 cells. The repair ability reflected by the results in the two cell lines was consistent.

CONCLUSIONThe radiosensitivities reflected by the results of the primary DNA damage and repair detected by both comet assay and colony assay in CNE-1 and 973 cells are consistent. It suggests that comet assay is a good method for detecting the radiosensitivity of tumor cells.

Adenocarcinoma ; pathology ; Carcinoma, Squamous Cell ; pathology ; Cell Line, Tumor ; Cell Survival ; radiation effects ; Comet Assay ; DNA Damage ; radiation effects ; DNA Repair ; drug effects ; Humans ; Lung Neoplasms ; pathology ; Nasopharyngeal Neoplasms ; pathology ; Particle Accelerators ; Radiation Dosage ; Radiation Tolerance

OBJECTIVETo study the combined damage-effects of low-intensity 2,450 MHz microwave (MW) with three chemical mutagens on human lymphocyte DNA.

METHODSDNA damage of lymphocytes exposed to microwave and(or) with chemical mutagens were observed at different incubation time (0 h or 21 h) with comet assay in vitro. Three combination-exposure ways of MW with chemicals were used: MW irradiation before chemical exposures, simultaneously exposed to MW and chemicals and MW irradiation after chemical exposures. The three chemical mutagens were mitomycin C (MMC, DNA crosslinker), bleomycin (BLM, radiometric agent), methyl methanesulfonate (MMS, alkylating agent). The exposure time of MW and chemical mutagens were 2 h and 3 h respectively.

RESULTSThe differences of comet tail length between MW group and control group were not significant when lymphocytes were incubated for 0 h or 21 h (P > 0.05). However, when lymphocytes were incubated for 21 h with 30.00 micro mol/L of MMC, the comet tail lengths of MW + MMC group, MW-MMC group and MMC + MW group were (18.00 +/- 5.96), (21.79 +/- 11.47) and (22.32 +/- 8.10) micro m respectively; while with 3.00 micro mol/L of MMC, the comet tail lengths were (8.99 +/- 3.75), (12.40 +/- 5.35) and (14.00 +/- 5.38) micro m respectively, which were significantly higher than those of corresponding MMC groups [(9.42 +/- 3.34) and (6.50 +/- 2.89) micro m, P < 0.01 or P < 0.05]. The DNA damage of MW plus BLM groups and MW plus MMS groups were not significantly different from the corresponding BLM and MMS groups (P < 0.05).

CONCLUSION2 450 MHz MW (5 mW/cm(2)) did not induce DNA damage directly, but could enhance the DNA damage effects induced by MMC. The synergistic effects of 2 450 MHz MW with BLM and MMS were not obvious.

Bleomycin ; pharmacology ; Comet Assay ; DNA ; drug effects ; genetics ; radiation effects ; DNA Damage ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Methyl Methanesulfonate ; pharmacology ; Microwaves ; adverse effects ; Mitomycin ; pharmacology ; Mutagens ; pharmacology ; Time Factors

Echinacea (E.) purpurea herb is commonly known as the purple coneflower, red sunflower and rudbeckia. In this paper, we report the curative efficacy of an Echinacea extract in gamma-irradiated mice. E. purpurea was given to male mice that were divided into five groups (control, treated, irradiated, treated before irradiation & treated after irradiation) at a dose of 30 mg/kg body weight for 2 weeks before and after irradiation with 3 Gy of gamma-rays. The results reflected the detrimental reduction effects of gamma-rays on peripheral blood hemoglobin and the levels of red blood cells, differential white blood cells, and bone marrow cells. The thiobarbituric acid-reactive substances (TBARs) level, Superoxide dismutase (SOD) and glutathione peroxidase (GSPx) activities and DNA fragmentation were also investigated. FT-Raman spectroscopy was used to explore the structural changes in liver tissues. Significant changes were observed in the microenvironment of the major constituents, including tyrosine and protein secondary structures. E. purpurea administration significantly ameliorated all estimated parameters. The radio-protection effectiveness was similar to the radio-recovery curativeness in comparison to the control group in most of the tested parameters. The radio-protection efficiency was greater than the radio-recovery in hemoglobin level during the first two weeks, in lymphoid cell count and TBARs level at the fourth week and in SOD activity during the first two weeks, as compared to the levels of these parameters in the control group.
Animals ; Antioxidants/isolation & purification/*pharmacology ; Blood Cell Count ; DNA Fragmentation/drug effects ; Echinacea/*chemistry ; Erythrocytes/drug effects/radiation effects ; *Gamma Rays ; Glutathione Peroxidase/metabolism ; Leukocytes/drug effects/radiation effects ; Lipid Peroxidation/drug effects ; Liver/*drug effects/enzymology/radiation effects ; Male ; Mice ; *Phytotherapy ; Plant Extracts/*pharmacology ; Radiation-Protective Agents/isolation & purification/pharmacology ; Random Allocation ; Superoxide Dismutase/metabolism

Inevitable human exposure to ionizing radiation from man-made sources has been increased with the proceeding of human civilization and consequently public concerns focus on the possible risk to human health. Moreover, Fukushima nuclear power plant accidents after the 2011 East-Japan earthquake and tsunami has brought the great fear and anxiety for the exposure of radiation at low levels, even much lower levels similar to natural background. Health effects of low dose radiation less than 100 mSv have been debated whether they are beneficial or detrimental because sample sizes were not large enough to allow epidemiological detection of excess effects and there was lack of consistency among the available experimental data. We have reviewed an extensive literature on the low dose radiation effects in both radiation biology and epidemiology, and highlighted some of the controversies therein. This article could provide a reasonable view of utilizing radiation for human life and responding to the public questions about radiation risk. In addition, it suggests the necessity of integrated studies of radiobiology and epidemiology at the national level in order to collect more systematic and profound information about health effects of low dose radiation.
DNA Damage/drug effects ; Environmental Exposure ; Humans ; Leukemia/epidemiology/etiology ; Neoplasms, Radiation-Induced/epidemiology ; *Radiation Dosage ; Radiation Tolerance ; *Radiation, Ionizing ; Radioactive Hazard Release ; Risk

OBJECTIVETo investigate the relationships between skin photoaging and point mutations in mitochondrial DNA (mtDNA) control region for replication of dermal fibroblast.

METHODSCultured dermal fibroblasts were treated by 8-methoxypsora len /ultraviolet A (8-MOP/UVA). mtDNA was extracted by one-step-method and th e PCR products of D-loop and adjacent transcription promoter (DLP(6)) fragment of mtDNA control region for replication were detected by polymerase chain reaction-single strain conformation polymorphism and direct sequencing.

RESULTSAfter treated by 8-MOP/UVA, point mutations of 414 T-->G of DLP(6) fragment of mtDNA control region for replication largely accumulated.

CONCLUSIONAccumulation of point mutations of DLP(6) fragment of mtDNA control region for replication may be closely associated with skin photoaging.

Adult ; Binding Sites ; Cells, Cultured ; DNA Replication ; DNA, Mitochondrial ; drug effects ; radiation effects ; Dermis ; cytology ; Fibroblasts ; cytology ; drug effects ; radiation effects ; Humans ; Male ; Methoxsalen ; pharmacology ; Photosensitizing Agents ; pharmacology ; Point Mutation ; Ultraviolet Rays

OBJECTIVETo assess DNA repair capacity of human lymphocytes with comet assay.

METHODSFresh lymphocytes form twelve 26-year old donors (6 males, 6 females) were exposed to ultraviolet C (UVC, 254 nm) at the dose rate of 1.5 J/m(2). The lymphocytes of each donor were divided into three parts: UVC group, UVC + aphidicolin (APC) group, UVC + novobiocin (NOV) group. DNA single strand breaks were detected with comet assay in UVC-irradiated cells and unirradiated cells incubated for 30, 60, 90, 120, 180 and 240 min. DNA repair rate (DRR) was calculated and served as an indicator of DNA repair capacity.

RESULTSThe maximum average comet tail length (MTL) in three groups appeared 90 min after UVC exposure. The DRR range of UVC group was 81.84% (62.84% - 98.71%); There was no significant difference in DRR between males and females (P > 0.05). However, the average DRRs of UVC + NOV group and UVC + APC group (52.98% and 39.57% respectively) were significantly lower than that of UVC group (P < 0.01).

CONCLUSIONComet assay is a rapid and simple screening test to assess DNA repair capacity. DRR, as an indicator, may express the individual DNA repair capacity.

Aphidicolin ; pharmacology ; Comet Assay ; methods ; DNA ; drug effects ; genetics ; radiation effects ; DNA Repair ; Enzyme Inhibitors ; pharmacology ; Female ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Male ; Novobiocin ; pharmacology ; Ultraviolet Rays

DNA-PKcs, the catalytic subunit of DNA-dependent protein kinase (DNA-PK), plays an important role in the nonhomologous end-joining (NHEJ) pathway of DNA double-strand breaks (DSBs) repair. To investigate the effects of DNA-PKcs down-regulation on cell growth and sensitization to low dose radiation (LDR), we transfected DNA-PKcs siRNA into human mammary epithelia cells MCF10F, then, detected the proliferation curve of the cells and the expression of protiens in DNA repair pathways. The results showed that DNA-PKcs gene silencing, induced by the transfection of DNA-PKcs siRNA could suppress significantly the cell proliferation and inhibit the expression of the DNA repair proteins, such as Ku80, ATM and P53 after 50 cGy 137Cs gamma-irradiation.The results suggested that DNA-PKcs gene silencing could increase the sensitivity of human breast epithelial cells to the LDR, which might be relative with the decrease of the proteins.
Breast ; cytology ; Cell Line ; DNA Repair ; drug effects ; radiation effects ; DNA-Activated Protein Kinase ; genetics ; Dose-Response Relationship, Radiation ; Epithelial Cells ; metabolism ; radiation effects ; Gene Silencing ; Humans ; Nuclear Proteins ; genetics ; RNA, Small Interfering ; genetics ; Transfection