[en] Highlights: • tBHQ increased HO-1 mRNA and protein levels in rat primary astrocytes. • tBHQ enhanced HO-1 gene transcription in an ARE-dependent manner. • tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. • Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. • Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction. - Abstract: Hemeoxygenase-1 (HO-1) is a phase II antioxidant enzyme that is primarily involved in detoxification and cytoprotection in a variety of tissues. However, the mechanism underlying HO-1 gene expression remains unclear. In the present study, we investigated the regulation of HO-1 expression in primary cultured astrocytes by using the natural antioxidant compound tertiary butylhydroquinone (tBHQ). We found that tBHQ increased HO-1 mRNA and protein levels. Promoter analysis revealed that tBHQ enhanced HO-1 gene transcription in an antioxidant response element (ARE)-dependent manner. In addition, tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. Small interfering RNA (siRNA) experiments demonstrated that Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. Thus, Nrf2 knockdown reduced the basal level of HO-1 expression but did not affect the fold induction by tBHQ. On the other hand, knockdown of c-Jun diminished tBHQ-mediated induction of HO-1 without affecting basal expression. The data suggest that Nrf2 generally modulates the basal expression of HO-1, while c-Jun mediates HO-1 induction in response to tBHQ. The results of co-immunoprecipitation assays demonstrated a physical interaction between Nrf2 and c-Jun in tBHQ-treated astrocytes. The results suggest that Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction in tBHQ-treated rat primary astrocytes

[en] Analysis of blood samples is an effective way of evaluating contamination by persistent pollutants such as polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxin/furans (PCDD/Fs), and polychlorinated biphenyls (PCBs) in human population. Concentrations of PBDEs, PCDD/Fs and PCBs were measured in the blood of laborers (n=13) working full time in two different municipal waste incinerator (MWI) plants and residents from the general population (n=22) living in areas near MWIs in Korea. The concentrations of PBDEs were found to be slightly higher in the blood of incineration workers (8.61-46.05 ng/g lipid; mean, 19.33 ng/g lipid; median, 15.94 ng/g lipid) in comparison to that of residents from the general population (7.24-28.89 ng/g lipid; mean, 15.06 ng/g lipid; median, 14.34 ng/g lipid). The total average PCDD/Fs and PCB TEQ concentration was 20.11 pg/g lipid, averaged over incineration workers (17.73 pg/g lipid) and the general population (21.52 pg/g lipid). In addition, the average total crude concentration of PCDD/Fs was 7.40 ng/g lipids, which was 4.1 times greater than for PBDEs. Congener specific analysis confirmed that BDE 47 was a predictive indicator for total PBDE concentration (correlation coefficient r=0.912), and that PCB 153 was a predictive indicator for total PCB concentration (r=0.967). The PBDE levels in human blood in Korea are much higher than those reported in other countries. The presence of the BDE 183 congener was characteristic in the blood of workers from an electronic dismantling facility in MWIs

No abstract available

[en] This study examined the possibility of using striped field mice as a biological dosimeter or indicator for the environmental radio-surveillance. For this study, the external morphological characteristics and isoenzymic types of dark-striped field mice were studied after they were captured. Among the morphological external characteristics, the dark-brown coat, dark back stripe, head-to-tail length, tail length, and ear length matched the taxonomical characteristics of dark-striped field mice. The analyses on L-lactate dehydrogenase, aspartate aminotransferase, and malate dehydrogenase revealed that one species of dark-striped field mice, called Apodemus agrarius, was inhabitated throughout a wide range of Korea. On the other hand, A. agrarius and ICR mice to analyze their survival rate and frequency of micronuclei in peripheral polychromatic erythrocytes after irradiation (0, 0.5, 1, 3, 5, 7, 9 Gy). The LD₅₀/₃₀ of A. agrarius and ICR mice were approximately 5 Gy and 7 Gy, respectively. The results of the study reveal that wild A. agrarius have a high potential as a biological monitoring system to determine the impact of radiation effect in areas such as those within the vicinity of nuclear power plants

[en] This study examined the possibility of using dark-striped field mice as a biological indicator for the environmental radio-surveillance. For this study, dark-striped field mice were caught from five areas of Kyonggi, Kyongsang, Chungchong and Cholla provinces. The external morphological characteristics and isoenzymic types of dark-striped field mice were studied after they were captured. Among the external morphological characteristics, the dark-brown coat, dark back stripe, head-to-tail length, tail length, and ear length matched the taxonomical characteristics of dark-striped field mice. The analyses on L-lactate dehydrogenase, aspartate aminotransferase, and malate dehydrogenese revealed that one species of dark-striped field mice, called Apodemus agrarius, was inhabitated throughout a wide range of Korea. On the other hand, the frequency of micronuclei in peripheral polychromatic erythrocytes to survived mice after irradiation also analyzed. The LD_50/30 of A. cgrarius and ICR mice were approximately 5 Gy and 7.9 Gy, respectively. The results of the study reveal that wild A. asrarius have a high potential as a biological monitoring system to determine the impact of radiation in areas such as those within the vicinity of nuclear power plants.

[en] We exposed ICR mice to low-dose (0.2 Gy) and low-dose-rate (0.7 mGy/h) -radiation (¹³⁷Cs) in the Low-dose-rate Irradiation Facility at the Radiation Health Research Institute to evaluate systemic effects of low-dose radiation. We compared the body and organ weights, number of blood cells (white and red blood cells and platelets), levels of biochemical markers in serum, and frequency of micronuclei in polychromatic erythrocytes between low-dose irradiated and nonirradiated control mice. The ICR mice irradiated with total doses of 0.2 and 2 Gy showed no changes in body and organ weights, number of blood cells (white and red blood cells), or frequency of micronuclei in the polychromatic erythrocytes of peripheral blood. However, the number of platelets (P = 0.002) and the liver weight (P < 0.01) were significantly increased in mice exposed to 0.2 and 2 Gy, respectively. These results suggest that a low-dose-rate of 0.7 mGy/h does not induce systemic damage. This dose promotes hematopoiesis in the bone marrow microenvironment and the proliferation of liver cells. In the future, the molecular biological effects of lower doses and dose rates need to be evaluated

[en] Regarding the management of nuclear power plants and the installation of facilities for radiation waste storage: social concerns over radiation safety are increasing. To understand how environmental radiation affects on human beings, the development of an reasonable monitoring system is required. The existing radio-environmental surveillance systems can be classified into physical and biological monitoring systems. The wild small animals and livestocks were reported to be effective biological indicators of environmental radiation This study investigated the possibility of using dark-striped field mice as a biological dosimetric model to assess the effect of radiation on the human environments. For this study, the criteria for the biological dosimeters of environmental radiation were established as the following: first, it should be an animal from a clear background of species; second, it should inhabit a broad range of areas and in considerable numbers; third, it should maintain identical ecological characteristics; fourth, it should be cohabitating with humans; fifth, it should have been consuming food found in their habitat; and finally, it should indicate a clear doseresponse relationship with high sensitivity. Based on such criteria, this study investigated the possibility of using dark-striped field mice as an effective biological dosimeter. Primarily, their species were classified based on their morphological external characteristics and isoenzymic patterns. The taxonomically classified darkstriped field mice, A. agrarius coreae, were then irradiated to investigate their radiation sensitivity based on the survival rate and hematology in this study

[en] This study evaluated the effects of low dose radiation on spermatogenic cells using the morphological characteristics of sperm in the caudal epididymis of ICR mice. In this study, six abnormal sperm shapes (amorphous heads, blunt hooks, excessive hooks, two heads and tails, folded tails and short tails) were observed at eight days after γ-irradiation (¹³⁷Cs, 0, 0.2, 0.5, 1, 2 or 4 Gy) with both a high-dose-rate (0.8 Gy/min) and a low-dose-rate (0.7 mGy/hr). Fewer abnormal forms of sperm were observed in low-dose-rate irradiated mice than in mice that received a high-dose-rate irradiation (P=0.002). The ratio of the dose rate effect among low-dose-rate irradiated mice to high-dose-rate irradiated mice was approximately 0.6. In addition, sperm with blunt hooks and two heads and tails significantly increased in number after irradiation, potentially providing an endpoint marker for estimating the effects of radiation. This study suggests that low-dose-rate (0.7 mGy/hr) radiation does not damage stem spermatogonia and probably stimulates repair in damaged spermatogonial stem cells in male mice. (author)

[en] The importance of low-dos and low-dose-rate radiation induced has been well recognized. Different systems have been used to study this phenomenon induced by low doses and low dose rates of radiation using various biological endpoints such as chromosomal aberration and micronuclei. These results clear showed the occurrence of adaptive response in terms of hematopoietic microenvironment the conditioning given in small fractions continuously seemed to be more effective

[en] To understand how environmental effects of radiation and radionuclides from radiation facilities relate to human beings, the development of an unmanned monitoring system is required. For the reasons of that, the International Atomic Energy Agency (IAEA) suggests a method to evaluate the effects of radiation emitted from radiation facilities on marine water, freshwater, and habitats for land animals and plants on its Technical Report Series 190, 288, and 332. Recently, International Commission on Radiological Protection (ICRP) Publication No. 91 (2003) was consecutively published to protect non-human animals and plants from environmental radiation and radioactive materials. This study examined the potential usefulness of dark-striped field mice as a biological indicator of enviro-radiation and radionuclides around nuclear power plants and radioactive waste storage facilities. For the purpose, dark-striped mice were collected in regions of Korea where there are no radiation facilities. Their external morphological characters and isoenzyme patterns were observed. As a result, the most dark-striped mice scattered in Korea are Apodemus agrarius coreae