Comparison of Single and Combined Use of Ergothioneine, Ferulic Acid, and Glutathione as Antioxidants for the Prevention of Ultraviolet B Radiation-Induced Photoaging Damage in Human Skin Fibroblasts

Ultraviolet B (UVB) irradiation can cause human skin damage or skin aging and wrinkle formation through photochemical reactions. Antioxidative substances may ameliorate UV damage. In this study, the anti-photoaging activity of three antioxidants—ergothioneine, ferulic acid, and glutathione—was investigated after UVB irradiation of Hs68 human skin fibroblast cells. The cells treated with these three antioxidants appeared similar to unirradiated control cells. UVB irradiation decreased cell viability by 26% compared to that of unirradiated control cells. However, the addition of either single or combined antioxidants enhanced cell viability after UVB irradiation. These three antioxidants can inhibit the production of reactive oxygen species (ROS) induced by the UVB irradiation of the Hs68 cells. Ergothioneine showed a greater inhibitory effect on matrix metalloproteinase-1 (MMP-1) performance than the other two antioxidants. IL-1 alpha was not detected in the Hs68 cells after exposure to a radiation dose of 150 mJ/cm2. Ergothioneine showed better restoration of type 1 procollagen than either ferulic acid or glutathione. Based on these results, the addition of two antioxidants was expected to restore type Ι procollagen production. In summary, these results demonstrate that the three tested antioxidants protect the skin against UVB-induced damage. The single and combined use of ergothioneine, ferulic acid, and glutathione has the potential for development as anti-photoaging materials in cosmetic applications.

Effect of irradiation on the survival and susceptibility of female Anopheles arabiensis to natural isolates of Plasmodium falciparum

BackgroundThe sterile insect technique (SIT) is a vector control strategy relying on the mass release of sterile males into wild vector populations. Current sex separation techniques are not fully efficient and could lead to the release of a small proportion of females. It is therefore important to evaluate the effect of irradiation on the ability of released females to transmit pathogens. This study aimed to assess the effect of irradiation on the survival and competence of Anopheles arabiensis females for Plasmodium falciparum in laboratory conditions.MethodsPupae were irradiated at 95 Gy, a sterilizing dose of gamma-rays from Caesium-137 source, and emerging adult females were challenged with one of 14 natural isolates of P. falciparum. Seven days post-bloodmeal (dpbm), irradiated and unirradiated-control females were dissected to assess the presence of oocysts. On 14 dpbm, oocyst rupture in mosquito midguts and sporozoite dissemination in head/thoraces were also examined. Two assays were performed to gauge the effect of irradiation on An. arabiensis survival. First, the survivorship of irradiated and unirradiated-control mosquitoes exposed to each parasite isolate was monitored. Second, how parasite infection and irradiation interact to influence mosquito lifespan was also assessed by including a group of uninfected unirradiated mosquitoes.ResultsOverall, irradiation reduced the proportion of infected mosquitoes but this effect was inconsistent among parasite isolates. Second, there was no significant effect of irradiation on the number of developing oocysts. Third, the proportion of ruptured oocysts at 14 dpbm was higher in irradiated- than in control-unirradiated females, suggesting that irradiation might speed up parasite development. Fourth, irradiation had varying effects on female survival with either a negative effect (assay 1) or no effect (assay 2).ConclusionCombining these effects into an epidemiological model could help quantifying the net effect of irradiation on malaria transmission in this system. Together, our data indicate that irradiated female An. arabiensis could contribute to malaria transmission, and highlight the need for perfect sexing tools which would prevent the release of females as part of SIT programs.

Upregulation of Plasminogen Activator Inhibitor-1 in Irradiated Recipient Arteries and Veins from Free Tissue Transfer Reconstruction in Cancer Patients

Background. Clinical studies have shown that radiotherapy can induce vascular disease at the site of exposure but is usually not clinically evident until years after treatment. We have studied irradiated human arteries and veins to better understand the underlying biology in search of future treatments. The aim was to investigate whether radiotherapy contributed to a sustained expression of plasminogen activator inhibitor-1 (PAI-1) in human arteries and veins. Methods. Irradiated arteries and veins were harvested, together with unirradiated control vessels, from patients undergoing free tissue transfer reconstruction at a median time of 90 weeks [5–650] following radiation exposure. Differential gene expression of PAI-1 was analysed, together with immunohistochemistry (IHC) and immunofluorescence (IF). Results. PAI-1 gene expression was increased in both arteries (p=0.012) and veins (p<0.001) in irradiated compared to unirradiated control vessels. IHC and IF indicated that cells expressing PAI-1 were located in the adventitia of both arteries and veins and colocalized with cells positive for CD68, CD45, and α-SMA in arteries and with CD45 and α-SMA in veins. Conclusion. The current study shows a sustained upregulation of PAI-1 in both arteries and veins after exposure to ionizing radiation, indicating a chronic inflammation mainly in the adventitia. We believe that the results contribute to further understanding of radiation-induced vascular disease, where targeting PAI-1 may be a potential treatment.

Erythropoietin Induction by Anemia Is Required for CFU-E Expansion During Erythroid Recovery From Sublethal Radiation Injury

Abstract 3218 The massive steady-state output of the erythron makes the erythroid lineage exquisitely sensitive to clastogenic injury. While the rapid loss of reticulocytes is well-described, the response of bone marrow progenitors and precursors to sublethal irradiation and the mechanisms underlying recovery of the erythron remain poorly defined. Following 4 Gy total body irradiation (TBI) in C57Bl/6 mice, functional colony assays were utilized to study the erythroid progenitor compartment, consisting of immature day 7 erythroid burst-forming units (BFU-E) and more mature day 3 BFU-E and erythroid colony-forming units (CFU-E). Multispectral imaging flow cytometry was used to quantify the erythroid precursor compartment, consisting of proerythroblasts and progressively more mature basophilic, polychromatophilic, and orthochromatic erythroblasts. At 2 days after 4 Gy TBI, greater than 95% of erythroid progenitors and precursors in the marrow were lost. A significant decrease in peripheral reticulocyte output and a gradual 9% drop in hematocrit accompanied this marrow loss over the first 3–4 days after radiation exposure. Following this initial injury and mild radiation-induced anemia, a robust recovery of the erythron began with a significant increase in day 3 BFU-E at 5 days post-radiation immediately followed by a rapid expansion of CFU-E at 5–6 days post-radiation to 200% of unirradiated control marrow. In contrast, day 7 BFU-E only partially recovered in a gradual linear fashion. Subsequent maturation of CFU-E resulted in progressive waves of erythroid precursors, reticulocytes, and mature red cells, creating a “ripple effect” following sublethal radiation injury. These results indicate that erythroid repopulation following radiation damage is centered on specific expansion and maturation of later erythroid progenitors (day 3 BFU-E and CFU-E). Erythropoietin (EPO) is known to be the primary regulator of the erythroid lineage, and day 3 BFU-E and CFU-E form the EPO-responsive compartment of the erythron. Therefore, we hypothesized that EPO may be the primary driving force underlying day 3 BFU-E/CFU-E expansion and subsequent erythroid recovery from radiation injury. Endogenous plasma EPO levels increased 13-fold above steady-state levels at 4 days post-radiation. This spike in EPO levels preceded the CFU-E expansion seen at 5–6 days post-radiation. To specifically determine both the etiology of the endogenous EPO spike and the necessity of supra-physiologic levels of EPO for erythroid recovery from radiation injury, we performed loss-of-function studies in which mice were transfused with packed red cells post-radiation to maintain a normal hematocrit. Prevention of the mild radiation-induced anemia by transfusion also prevented the increase in endogenous EPO and significantly abrogated day 3 BFU-E/CFU-E recovery. These findings directly link radiation-induced anemia with EPO induction and erythroid lineage reconstitution. Gain-of-function studies were performed to determine whether EPO is sufficient to drive erythroid expansion after radiation injury. Administration of exogenous EPO at 1 hour post-radiation significantly advanced the timing of CFU-E expansion and subsequent recovery of the erythron. In addition, the accelerated synchronous wave of recovery following exogenous EPO very closely mirrored the physiological wave of recovery during the endogenous EPO response, indicating that the previously observed “ripple effect” is an inherent component of EPO-induced erythroid recovery from radiation injury. Finally, administration of EPO at 4 days post-radiation, at the peak of the endogenous EPO response, further enhanced CFU-E recovery to over 330% of unirradiated control levels, providing additional evidence that EPO drives expansion of irradiated CFU-E. These studies, taken together, indicate that the anemia-induced EPO response following radiation injury is both necessary and sufficient for CFU-E expansion that leads to recovery of the erythron. A better understanding of the response of the erythroid lineage to clastogenic injury will ultimately lead to improved therapies to protect and mitigate the hematopoietic system from radiation and chemotherapy damage. Disclosures: No relevant conflicts of interest to declare.

UV-B Irradiation Increases Susceptibility of Mice to Malarial Infection

ABSTRACT We here examined whether exposure of mice to UV-B affected their susceptibility to the murine malaria parasite Plasmodium chabaudi. When BALB/c mice with depilated skin were irradiated with UV-B and subsequently infected with the parasite, 80 to 100% of the UV-B-irradiated mice died within 12 days of infection with a sublethal dose. In addition, UV-B irradiation of C57BL/10 (B-10) mice, which are otherwise naturally resistant to the parasites, rendered them susceptible, and 100% of irradiated B-10 mice died within 11 days postinfection. The level of plasma gamma interferon (IFN-γ) in unirradiated B-10 mice at 5 days after infection increased to 566 pg/ml, whereas the UV-B exposure of mice impaired the production of IFN-γ, which showed a maximum level of 65 pg/ml in response to the parasite infection. The maximum level of plasma interleukin-10 in UV-B-irradiated mice in response to the parasite infection was ∼1,100 pg/ml, which was approximately fourfold higher than the maximum level in unirradiated control mice. When UV-B-irradiated B-10 mice were administered murine recombinant IFN-γ after infection, the mice regained parasite resistance. These results demonstrated that the UV-B exposure of mice enhances the susceptibility to the malaria parasites and suggested that the enhanced susceptibility following UV-B exposure was mediated by impairment of IFN-γ production in response to the parasite infection.

Sensory and Microbial Quality of Chicken as Affected by Irradiation and Postirradiation Storage at 4.0°C

Chickens were subjected to gamma irradiation doses of 2.5, 5.0,7.5, and 10.0 kGy using a semi-commercial gamma irradiation facility. The irradiated and unirradiated (control) chickens were stored at 4.0°C, and samples were drawn at day 0 and at 3-day intervals up to 21 days for sensory and microbiological analyses. All irradiation doses (2.5 to 10.0 kGy) had little effect on the sensory acceptability (appearance, odor, texture, taste) of both raw and cooked chicken (breast and thigh). Irradiation extended the time during which these characteristics were acceptable. Moreover, juiciness and tenderness of cooked chicken were only slightly affected by irradiation, and chickens were not rejected even after 21 days of storage. A dose of 2.5 kGy seemed adequate to extend the shelf life of chicken by 12 days, and increasing the dose level above 2.5 kGy gave little if any additional benefit as far as total and psychrotrophic bacterial counts are concerned. Moreover, the dose of 2.5 kGy was enough to destroy Salmonella, Yersinia, and Campylobacter species and coliforms. The study also showed that yeasts of the genera Candida, Saccharomyces, and Alternaria started to grow on day 12 in samples treated with ≥5.0 kGy, but not in samples treated with &lt;5.0 kGy.

SPONTANEOUS MITOTIC RECOMBINATION AND EVIDENCE FOR AN X-RAY-INDUCIBLE SYSTEM FOR THE REPAIR OF DNA DAMAGE IN DROSOPHILA MELANOGASTER

ABSTRACT Spontaneous mitotic recombination in the left arm of chromosome 3 was examined in both unirradiated control flies and sibs irradiated early in development by determining the sizes and frequencies of multiple-wing-hair (mwh) clones in the wing blade of heterozygous mwh/+ flies. Approximately 16% of the spontaneous mwh clones arise from events generating cells with normal division rates. The remaining 84% result from events generating cells with an average cell division rate one-third that of the surrounding cells; these are thought to result from events that generate aneuploid cells. Such clones probably arise from a failure correctly to repair spontaneous DNA damage. The frequency of spontaneous events late in development decreases significantly after irradiation as much as 150 hours earlier in development. The suppression of spontaneous events decreases with a longer period of time between irradiation and the final cell divisions in the wing blade. These results suggest the existence of a repair system for DNA damage in Drosophila that is induced by irradiation. The decrease in effect with time following irradiation could result from slow degradation or dilution by subsequent cell growth and division.

RADIOSENSITIVITY OF THE EXTRA-LARGE (XL) MUTANT OF TRIBOLIUM CONFUSUM (COLEOPTERA: TENEBRIONIDAE)

The radiosensitivity of a wild-type (+/+) laboratory strain of Tribolium confusum Jacquelin duVal was compared with that of an extra-large (xl/xl) strain known to differ in only a single locus. Differences in both longevity and fecundity between the two strains after irradiation were very highly significant (p < 0.001), but real differences between strains in these biological characteristics may have produced the differential response. When differences in longevity and fecundity were corrected for the unirradiated control, there were only minor differences in response between the two strains. Thus, physical size alone apparently did not greatly influence the comparative radiosensitivity for the two strains of this species.

Gamma Irradiation as a Means of Extending the Storage Life of Haddock Fillets

Studies of the storage life of iced haddock (Melanogrammus aeglefinus) fillets after treatment with doses of gamma radiation of 75,000, 150,000, and 250,000 rads, have shown that a useful extension of the storage life is made possible by irradiation. The fillets irradiated with the 75,000-rad dose and assessed after cooking became unacceptable after about 25 days at 0 °C. The unirradiated control became unacceptable after 12 days. Fillets irradiated at the two higher levels were of lower quality initially than the fillets irradiated at the 75,000-rad level but showed no significant decrease in acceptability up to 27 days storage in ice. Raw fillets developed an objectionable odour and appearance just prior to becoming unacceptable to the taste panel.