Long-term exposure to cypermethrin and piperonyl butoxide cause liver and kidney inflammation and induce genotoxicity in New Zealand white male rabbits

Cypermethrin (CY) is a frequently used class II pyrethroid pesticide, while piperonyl butoxide (PBO) plays a major role in the pesticide formulation of synthetic pyrethroids. Synthetic pyrethroids are metabolized in mammals via oxidation and ester hydrolysis. PBO can prevent the metabolism of CY and enhances its pesticide effect. While this potentiation effect reduces the amount of pesticide required to eliminate insects, it is not clear how this mixture affects mammals. In our in vivo experiment, New Zealand white male rabbits were exposed to low and high doses of CY, PBO, and their combinations, for 4 months. Genotoxicity and cytotoxicity were monitored by measuring binucleated cells with micronuclei (BNMN), micronuclei (MN) and the cytokinesis block proliferation index (CBPI) in lymphocytes. After two months of exposure, a statistically significant increase in the frequency of BNMN was observed for all exposed animals (p < 0.001) in a dose-dependent way. MN were significantly elevated compared to controls (p < 0.001), with high dose groups reaching a 442% increase when co-exposed. BNMN and MN continued to increase after four months. Histopathological examination of lesions showed damage involving inflammation, attaining lymphoplasmatocytic infiltration in the high dose groups. Both CY and PBO cause liver and kidney inflammation and induce genotoxicity.     

Involvement of oxidative stress in mutagenicity and apoptosis caused by dental resin monomers in cell cultures

OBJECTIVE: This investigation studied the possibility that apoptosis as well as mutagenicity induced by resin monomers are mediated by oxidative stress. METHODS: A range of dilutions of three resin monomers (GMA, TEGDMA, and HEMA) was added to culture medium (DMEM/10% FBS), of V79-4 fibroblasts and RPC-C2A pulp cells for 24 h. Their cytotoxic effects were measured by a colorimetric functional assay (MTT). Chromosomal aberration induced by the resin monomers was investigated by counting micronuclei in V79-4 cells. The effects of the resin monomers on DNA fragmentation were viewed by agarose gel electrophoresis of DNA, isolated from RPC-C2A pulp cells that were treated by resin compounds. Resin monomer-induced apoptosis was further confirmed by flow cytometry (staining with both annexin V-FITC and PI). RESULTS: All monomers exhibited a dose-dependent cytotoxic effect, and the ranking of the cytotoxicity based on TC50 was GMA > TEGDMA > HEMA. The resin monomer-induced cytotoxicity was significantly decreased by co-treatment with N-acetylcystein (NAC), an antioxidant. The authors also confirmed a dose-dependent genotoxicity of the resin monomers that had induced micronucleated cells in V79-4 fibroblasts. Similar to the effects on cytotoxicity, NAC reduced the numbers of micronuclei in comparison with those generated by the resin monomers. The preventive effects of NAC were also observed in monomer-induced apoptosis in RPC-C2A cells. A DNA ladder pattern, characteristic of apoptosis, was shown at cytotoxic concentrations, but NAC blocked the resin monomer-mediated DNA fragmentation. The preventive effects of NAC on apoptosis were confirmed by Annexin V staining. Cells exposed to 300 microM GMA, 7 mM TEGDMA, or 14 mM HEMA for 24 h showed a significant increase in apoptotic cells, while NAC co-treatment caused a reduction in apoptotic cells compared to controls. SIGNIFICANCE: These findings suggest that glutathione depletion and oxidative stress are responsible for GMA, TEGDMA, and HEMA-induced mutagenicity and apoptosis.     

铬酸盐低水平长期职业接触与劳动者早期健康效应

目的: 从肺功能、免疫毒性及遗传损伤方面综合探讨铬酸盐长期低水平职业接触对劳动者健康的影响,以期发现潜在的早期健康效应标志物。方法: 以内蒙古某职业卫生环境监测下长期符合国家标准的电镀企业22名铬酸盐接触工人和44名非铬酸盐接触工人为研究对象,问卷调查收集工人基本情况、吸烟饮酒史、疾病史等信息;分别采用便携式肺功能仪、电感耦合等离子体质谱法和胞滞分裂阻滞微核试验测定铬酸盐接触工人肺功能、全血铬(whole blood Cr, WB-Cr)和外周血淋巴细胞微核率(micronuclei frequency, MNF);采用流式微球阵列法检测两组工人血清细胞因子IL-1β、IL-6、IL-8、IL-10、IL-12P70和TNFα含量,分析铬酸盐接触对上述生物内暴露、肺功能、免疫应答、遗传损伤各指标的影响及不同损伤效应间的相关性。结果: (1)铬酸盐接触工人平均工龄为31年,WB-Cr浓度为1.11~4.19 μg/L,按中位数1.72 μg/L将铬酸盐接触者分为高暴露组和低暴露组,高暴露组平均WB-Cr水平(2.17 μg/L)高于低暴露组(1.58 μg/L)和健康人群参考值(1.74 μg/L, P<0.05);(2)肺功能检测发现10名(45.45%)铬酸盐接触工人出现单个或多个肺功能指标异常情况,其中大气道损伤指标呼气流量峰值(peak expiratory flow,PEF)与小气道损伤指标每分钟最大通气量(maximum ventilation volume,MVV)和FEF25%~75%分别与WB-Cr呈负相关(r=-0.53,P<0.05; r=-0.52, P<0.05; r=-0.44,P<0.05);(3)铬酸盐接触工人血清IL-1β,IL-6,IL-8和TNFα均高于对照人群(P<0.05), 且TNFα与WB-Cr间存在正相关,各细胞因子之间两两正相关(P<0.05);(4)铬酸盐接触工人淋巴细胞MNF平均为1.341%, 高于一般人群参考值0.436%(P<0.01),Poisson多元回归结果显示高暴露工人MNF高于低暴露工人,OR(95%CI)值为1.323(1.049,1.669);(5)多元线性回归结果显示肺功能指标用力呼气中段流量 (forced expiratory flow rate 25%~75%,FEF25%~75%)随TNFα升高而降低(P<0.05),未发现其他细胞因子、MNF、肺功能指标之间存在有统计学意义的相关性。结论: 长期低水平铬酸盐职业接触引起劳动者肺功能下降、免疫炎症反应、遗传损伤的发生,其中局部或全身炎症反应与肺功能下降有关。肺功能指标PEF、FEF25%~75%、MVV,血清细胞因子IL-1β、IL-6、IL-8、TNFα水平和外周血淋巴细胞微核率可能作为铬酸盐暴露的早期健康效应标志物。     

Effects of 2-deoxy-D-glucose on glycolysis,proliferation kinetics and radiation response of human cancer cells

The effects of 2-deoxy-D-glucose (2-DG) on energy metabolism, cell proliferation kinetics, radiation-induced DNA repair, and micronuclei formation in HeLa cells have been studied. Results show that the 2-DG induced modifications of the radiation effects are biphasic: (1) at high 2-DG conceentrations (>2.5 mM), DNA repair is inhibited and manifestation of radiation damage is enhanced as observed by an increase in the radiation (X ray) induced micronuclei formation; (2) lower concentrations of 2-DG (<2.5 mM) do not inhibit DNA repair and a decrease in the frequency of micronuclei formation is observed. These data, in correlation with the effects of 2-DG on glycolysis and cell proliferation kinetics, can be explained by the hypothesis that 2-DG induced modifications of radiation effects arise as a result of energy linked differential inhibitions of pathways of repair andfixation of DNA damage. Implications for cancer therapy are discussed.     

Radiobiological effect of 99mTechnetium-MIBI in human peripheral blood lymphocytes: ex vivo study using micronucleus/FISH assay

99mTc-MIBI is currently used, for cardiac investigations, for parathyroid thyroid imaging and evaluation of various tumours. It has been demonstrated that 99mTc-MIBI is specifically taken up by the human peripheral blood lymphocytes (HPBL), cells which are known to be highly radiosensitive. To evaluate the possible chromosomal damage induced on HPBL by their in vitro exposure to increasing activities of 99mTc-MIBI and also to establish whether HPBL undergo apoptosis or necrosis after in vitro exposure to 99mTc-MIBI. Blood from two healthy donors were irradiated, incubated in vitro with increasing activities of 99mTc-MIBI corresponding to absorbed doses ranging from 1 microGy, 100 microGy, 1 cGy, 10 cGy, 50 cGy to 1 Gy. The cytokinesis block micronucleus (MN) assay was used and the frequency of binucleated cells (BN) with MN (MNBN) was analyzed in cultured HPBL (in either the G0- or G1- and S1-phase of the cell cycle). The fluorescence in situ hybridization (FISH) with pancentromeric probes was also applied to study the MN regarding whole chromosomes or acentric fragments. Apoptosis induction by 0.1 Gy of 99mTc-MIBI in HPBL was quantified using annexin-V test. The frequencies of MNBC were similar in control cultures and in HBPL cultures exposed to 1 microGy, 100 microGy and 1 cGy. However, they were significantly higher (P<0.05 versus controls and lower doses) after one treatment exposure to 0.25 mCi of 99mTc-MIBI (corresponding to 10 cGy) or more but the percentages of MNBN with 10 cGy, 50 cGy and 1 Gy did not differ significantly. The increase of MNBN was more pronounced (P<0.05) for cells irradiated during G1 phase than for those irradiated during G0 or S1. Using FISH, 80-90% of the MN were centromere negative. Although small, the absolute number of MN positive for centromeric signal and presumably containing whole chromosomes increased with doses. There is a statistically significant (P=0.001 and 0.006) increase of both apoptotic cells and necrosis, respectively, as compared to control cells in two times studied (24 and 36 h). Chromosomic damages can thus be demonstrated in HPBL after in vitro exposure of blood to at least 0.25 mCi of 99mTc-MIBI corresponding to one absorbed dose of 10 cGy, and for this dose, apoptosis and necrosis phenomenons were detected.     

Effects of uranium ore dust on cultured human lung cells

Effects of uranium ore dust on cell proliferation, lipid peroxidation and micronuclei formation were compared with silica (DQ12) and titanium oxide in normal human distal airway epithelial cells (NHDE), human lung cancer cells (A549) and human lung fibroblast cells. Cell proliferation was significantly inhibited with uranium ore dust and silica but not with titanium oxide. Lipid peroxidation was significantly enhanced only with uranium ore dust. Micronuclei formation was significantly stimulated with uranium ore dust in A549 and NHDE cells, but not in fibroblast cells. Silica stimulated micronuclei formation only in A549 cells. The results showed the outstanding effect of uranium ore dust on lipid peroxidation and micronuclei formation in human lung cells compared to silica and titanium dioxide.     

新癀片对荷S_(180)小鼠的肿瘤生长及免疫功能的影响

目的 :探讨新癀片对荷S180 小鼠的肿瘤生长及免疫功能的影响。方法 :采用小鼠S180 实体瘤模型 ,以新癀片灌胃治疗 ,观察新癀片对荷S180 小鼠的瘤体比、抑瘤率、胸腺和脾脏的脏器系数及骨髓PCE微核率的变化。结果 :新癀片具有减少瘤体比、明显抑制肿瘤生长、增加脾重和外周血白细胞数目的作用 ,但对骨髓PCE微核率无明显影响。结论 :新癀片具有抑制S180 肿瘤生长和增强其细胞免疫的功能。     

Health impact of air pollution to children

Health impact of air pollution to children was studied over the last twenty years in heavily polluted parts of the Czech Republic during. The research program (Teplice Program) analyzed these effects in the polluted district Teplice (North Bohemia) and control district Prachatice (Southern Bohemia).     

Homocysteine induces DNA damage and alterations in proliferative capacity of T-lymphocytes: a model for immunosenescence?

Homocysteine (Hcy) appears to exert different effects on immune functions possibly contributing to age-related pathological states, including vascular diseases, immune dysfunction, and Alzheimer’s disease. However, molecular mechanisms underlying Hcy toxicity need to be better characterized. Since T cells are a suitable model to address the possible role of replicative senescence during the in vivo aging, we investigated the effects of high Hcy concentrations on mitogen-activated lymphocytes, with regard to evaluation of DNA damage and cell cycle alterations. Cultured human peripheral blood lymphocytes were stimulated with mitogenic concanavalin A (5 μg/ml) for 48 h in the presence or absence of Hcy (1 mM). Both flow cytometric analysis and caspase-3 activity assay showed an increased rate of apoptosis in Hcy-treated lymphocyte cultures compared to controls. Further, Hcy exposure caused DNA fragmentation as evaluated by single cell gel electrophoresis showing the occurrence of comets. Cytokinesis-block micronucleus assay, performed after addition of cytochalasin B (5 μg/ml) and incubation up to 72 h, revealed a significantly higher frequency of micronucleated/binucleated cells in Hcy-treated cultures compared to controls (P < 0.001). Hcy also reduced cyclin B expression in comparison to control cultures, while cyclin D levels were not significantly affected. Cell cycle alterations, such as the inability of cells to enter into mitosis, could be related with DNA damage. These findings provided a link between perturbation of lymphocyte proliferation homeostasis and commitment towards apoptosis. Our results suggest the involvement of Hcy in the altered immune function associated with age and disease pathology.     

A cytogenetic approach to the effects of low levels of ionizing radiations on occupationally exposed individuals

The aim of the present study was to assess occupationally induced chromosomal damage in hospital workers exposed to low levels of ionizing radiation. Thirty-two interventional cardiologists, 36 nuclear medicine physicians and 33 conventional radiologists were included in this study, along with 35 healthy age- and sex-matched individuals as the control group. We used conventional metaphase chromosome aberration (CA) analysis, cytokinesis-block micronucleus (MN) assay as important biological indicators of ionizing radiation exposure. Occupational dosimetry records were collected over the last year (ranged from 0.25 to 48 mSv) and their whole life exposure (ranged from 1.5 to 147 mSv). The results showed significantly higher frequencies of dicentric and acentric CAs (p < 0.001) and MN (p < 0.01) in all exposed groups than in the controls. Taking all the confounding factors into account, no obvious trend of increased chromosomal damages as a function of either duration of employment, exposed dose, sex or age was observed. Interventional cardiologists had the highest rates of CA and MN frequencies between the worker groups, though the differences were not significant. These results indicate that long term exposure to low dose ionizing radiation could result in DNA damage. Hence, the personnel who work in the hospitals should carefully apply the radiation protection procedures.