五氯酚钠对鲤鱼肾细胞DNA损伤的体内和体外研究

目的 研究五氯酚钠对鲤鱼肾细胞DNA的损伤效应.方法 选择健康鲤鱼,体内染毒实验:分别设3个五氯酚钠(Na-PCP)染毒组(14.4、28.8、144.0μg/L)和1个对照组(蒸馏水),每组3尾鲤鱼,染毒72 h.体外染毒实验:收集健康鲤鱼肾细胞悬液,分别设3个Na-PCP染毒组(14.4、28.8、144.0μg/L)和1个对照组(蒸馏水),染毒1.5 h.体内、外实验结束后,均采用单细胞凝胶电泳试验检测细胞DNA损伤程度,指标包括Olive尾距、彗尾长、尾距、彗尾DNA含量.结果 体内染毒结果显示,14.4、28.8、144.0μg/L组Olive尾距、彗尾长、尾距、彗尾DNA含量均高于对照组,差异均有统计学意义(P＜0.05,P＜0.01).体外染毒结果显示,除28.8 μg/L组外,14.4、144.0 μg/L组Olive尾距、彗尾长、尾距、彗尾DNA含量均高于对照组,差异均有统计学意义(P＜0.01).体内染毒的0、14.4μg/L组Olive尾距小于体外染毒,差异均有统计学意义(P＜0.05);而体内染毒的28.8、144.0 μg/L组Olive尾距大于体外染毒,差异均无统计学意义(P＞0.05).结论 五氯酚钠能够诱导鲤鱼肾细胞DNA损伤.     

Renal Changes and Apoptosis Caused By Subacute Exposure To Aroclor 1254 in Selenium-deficient and Selenium-supplemented Rats

Aroclor 1254 (A1254), a mixture of polychlorinated biphenyls, exerts hepatic, renal, and reproductive toxicity in rodents. This study aimed to determine a protective role of selenium on histopathological changes, oxidative stress, and apoptosis caused by A1254 in rat kidney. It included a control group, which received regular diet containing 0.15 mg/kg Se (C), a Se-supplemented group (SeS) receiving 1 mg/kg Se, a Se-deficient group (SeD) receiving Se-deficient diet of ≤0.05 mg/kg Se, an A1254-treated group (A) receiving 10 mg/kg of Aroclor 1254 and regular diet, an A1254-treated group receiving Se-supplementation (ASeS), and an A1254-treated group receiving Se-deficient diet (ASeD). Treatments lasted 15 days. After 24 h of the last dose of A1254, the animals were decapitated under anaesthesia and their renal antioxidant enzyme activities, lipid peroxidation (LP), glutathione, protein oxidation, and total antioxidant capacity levels measured. Histopathological changes were evaluated by light and electron microscopy. Apoptosis was detected with the TUNEL assay. Kidney weights, CAT activities, and GSH levels decreased significantly in all A1254-treated groups. Renal atrophic changes and higher apoptotic cell counts were observed in the A and ASeD groups. Both groups also showed a significant drop in GPx1 activities (A – 34.92 % and ASeD – 86.46 %) and rise in LP (A – 30.45 % and ASeD – 20.44 %) vs control. In contrast, LP levels and apoptotic cell counts were significantly lower in the ASeS group vs the A group. Histopathological changes and renal apoptosis were particularly visible in the ASeD group. Our findings suggest that selenium supplementation provides partial protection against renal toxicity of Aroclor 1254.     

Toxicopathological Changes Induced By Combined Exposure To Noise and Toluene in New Zealand White Rabbits

Noise and toluene can have significant adverse effects on different systems in the human body, but little is known about their combination. The aim of this study was to see how their combined action reflects on serum levels of inflammatory cytokines tumour necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β), body weight, and pathological changes in the heart, lung, stomach, and spleen tissues. To do that we exposed New Zealand rabbits to 1000 mg/L toluene and 100 dB of white noise in a chamber specifically designed for the purpose over two consecutive weeks. Serum levels of TNF-α and IL-1β were measured with the enzyme-linked immunosorbent assay (ELISA), whereas Bax and Bcl-2 expressions in tissues were determined with real-time polymerase chain reaction (PCR). Noise and toluene changed TNF-α and IL-1β serum levels on different days following the end of exposure and significantly increased the Bax/Bcl-2 ratio in the lung and spleen. In addition, they induced different pathological changes in the heart, lung, spleen, and stomach tissues. This study has confirmed that exposure to noise and toluene can induce a range of toxicopathological changes, probably by inducing inflammatory pathways and apoptosis, but their combined effects look weaker than those of its components, although histopathological findings suggest the opposite.Key words: body weight, environmental exposure, heart, IL-1β, industrial toxicology, apoptosis, lung, spleen, stomach, TNF-α     

Radiotherapy with fraction size of 2.25 Gy in T1-2 laryngeal and hypopharyngeal cancer

This study was carried out to evaluate the influence of fraction size 2.25 Gy on local control of T1 and T2 laryngeal and hypopharyngeal cancers. Between August 2002 and December 2010, 80 patients with T1 and T2 laryngeal or hypopharyngeal cancers were treated with definitive radiotherapy with a fraction size of 2.25 Gy. Primary sites were the larynx in 69 and the hypopharynx in 11. Fifty-three patients were T1 and 27 were T2. All patients'' pathology was squamous cell carcinoma except one carcinosarcoma. Radiotherapy was delivered 5 days/week with a 4-MV photon beam up to a total dose of 63.0 Gy. Median treatment time was 41 days. Statistical analysis of survival was calculated using the Kaplan–Meier method. No acute toxicity greater than grade 2 (CTCAE ver. 3.0.) including mucositis and dermatitis was observed. All but one patient had a complete response. The partial response patient received salvage surgery. The median follow-up period was 47 months (ranging from 4 to 108 months). No late toxicity greater than 1 was observed. Nine patients developed recurrence, seven local and two neck lymph nodes. Three patients died, one from laryngeal cancer and two from intercurrent diseases. The 5-year local control rates (LCRs) in the entire group, larynx T1, larynx T2 and hypopharynx T1 were 85.8%, 97.6%, 70.1% and 85.7%, respectively. The LCRs of T1 improved compared with our historical control, but not those of T2. The 2.25-Gy fraction size is safe and may have the potential to achieve good LCR in T1 lesions.     

甲醛和乙苯联合染毒对小鼠脑组织DNA的损伤

[目的]探讨不同浓度甲醛和乙苯单独及联合染毒对小鼠脑组织DNA的损伤作用,分析其联合作用的类型.[方法]采用4×4析因设计,利用单细胞凝胶电泳实验方法,研究甲醛(0、0.2、2.0、20.0 mg/kg)和乙苯(0、50、250、500 mg/kg)单独以及二者联合染毒后小鼠脑组织DNA的损伤情况. [结果]甲醛和乙苯单独及联合染毒组小鼠脑细胞彗星拖尾率、尾部DNA含量和尾矩均高于对照组(P＜0.05);彗星细胞拖尾率随染毒剂量的增加而增大,高剂量联合组小鼠的拖尾率高于其他各组(P＜0.05);尾部DNA含量和尾矩均随乙苯剂量的增加而增大;低、中剂量染毒组的尾部DNA含量和尾矩随着甲醛剂量的增加而增大,但高剂量组减小;二者之间存在交互作用(P＜0.05). [结论]甲醛和乙苯均可对小鼠脑组织造成DNA的损伤,联合染毒组的脑组织损伤程度重于单独染毒组,二者的联合效应表现为协同作用.     

滴滴涕与纳米二氧化钛对人胚肝细胞DNA损伤作用的协同效应

[目的]观察滴滴涕（DDT）及纳米二氧化钛（nano-TiO2）单独及联合体外染毒对人胚肝细胞株（L-02）内活性氧（ROS）含量及DNA损伤的影响。[方法]生长良好的L-02细胞,分别加入0.001、0.01、0.1μmol/L的DDT,0.01、0.1、1μg/mL的nano-TiO2,以及上述各浓度的DDT和nano-TiO2联合剂量,染毒时间均为24 h;运用DCFH-DA作为荧光探针,采用流式细胞检测技术检测DDT与nano-TiO2联合作用下L-02细胞内ROS含量,运用碱性和中性两种彗星试验检测各组DNA断裂损伤程度。[结果]0.01μmol/L以上浓度组DDT单独作用24 h引起ROS升高（P〈0.05）和DNA损伤增加（P〈0.05）;各浓度nano-TiO2单独染毒均不能引起DNA损伤增加（P〉0.05）,但1μg/mL单独染毒可引起ROS升高（P〈0.05）。各剂量组单独染毒24 h后均无明显的DNA双链损伤（P〉0.05）,但可导致DNA单链断裂损伤。析因分析结合反应曲面模型显示两种受试物联合染毒可协同增加ROS水平与DNA损伤作用（P〈0.05）。[结论]DDT和nano-TiO2联合作用可协同增加各自对DNA单链断裂水平的影响,诱导产生ROS导致DNA损伤是DDT和nano-TiO2引起机体损伤的主要机制之一。     

应用单细胞凝胶电泳研究镉对大鼠肝细胞DNA损伤的影响

目的 研究一定剂量的氯化镉对离体和在体大鼠肝细胞ＤＮＡ损伤的作用。方法 应用单细胞凝胶电泳或慧星试验。结果 在２．１８５μｍｏｌ／Ｌ、４．３７５μｍｏｌ／Ｌ、８．７５μｍｏｌ／Ｌ、１７．５０μｍｏｌ／Ｌ、３５．００μｍｏｌ／Ｌ的剂量条件下,氯化镉均可引起离体大鼠肝细胞ＤＮＡ损伤。５μｍｏｌ／ｋｇ、１０μｍｏｌ／ｋｇ、２０μｍｏｌ／ｋｇ的氯化也可引起在体大鼠肝细胞ＤＮＡ损伤。氯化镉引起的离体和在体在     

微囊藻毒素与饮用水有机提取物联合致HepG_2细胞DNA损伤的研究

目的探讨微囊藻毒素(MC-LR)与管网末梢水有机提取物联合致HepG2细胞DNA损伤的作用。方法于2007年7月采集某市的管网末梢水,分别选用XAD-2、XAD-8大孔吸附树脂以及两者等体积配制的复合树脂(简称XAD-2/8)富集为100、10和30ml/ml的有机物。应用彗星试验,研究MC-LR与管网末梢水有机提取物联合致HepG2细胞(1×105个/孔)DNA损伤的作用。结果与溶剂对照组相比,0.5μg/mlMC-LR染毒组可使HepG2细胞Olive尾矩值显著增加(P0.01)。较高浓度(0.1、0.5μg/ml)MC-LR与经XAD-2树脂富集的有机物(100ml/ml)联合染毒时,所诱导的HepG2细胞Olive尾矩值较之相应的单独作用组显著增加(P0.01);0.05、0.1、0.5μg/mlMC-LR与经XAD-8树脂富集的有机物(10ml/ml)联合染毒时,所诱导的HepG2细胞Olive尾矩值较之相应的单独作用组显著增加(P0.01);较高浓度(0.1、0.5μg/ml)MC-LR与经XAD-2/8树脂富集的有机物(30ml/ml)联合染毒时,所诱导的HepG2细胞Olive尾矩值较之相应的单独作用组显著增加(P0.01)。运用析因分析统计学方法,发现MC-LR与3种树脂富集的饮用水有机提取物存在交互作用(P0.01)。结论饮用水有机提取物与MC-LR之间存在协同作用,MC-LR可以极大地增强饮用水中有机物的致DNA损伤作用。     

低剂量纳米二氧化钛和乙酸铅联合诱导人胚肝细胞DNA损伤与修复作用

目的研究纳米二氧化钛（titanium dioxide nanoparticles,nano-TiO₂）与乙酸铅（PbAc）联合染毒对人胚肝细胞（L-02）的DNA损伤及修复作用。方法将L-02细胞分别以1μg/ml乙酸铅溶液和10、1、0.1、0.01、0.001μg/ml纳米二氧化钛溶液以及1μg/ml乙酸铅+0.001、0.01、0.1、1、10μg/ml纳米二氧化钛溶液处理24 h,同时,以1‰二甲基亚砜（dimethyl sulfoxide,DMSO）为阴性对照,30μmol/L H₂O₂为阳性对照。测定L-02细胞DNA的Olive尾矩、DNA加合物8-羟基脱氧鸟苷（8-OHdG）和DNA损伤修复酶8-羟基鸟苷DNA糖苷酶同源物1（OGG1）的水平。结果与阴性对照组比较,1μg/ml乙酸铅+1、10μg/ml纳米二氧化钛组L02细胞DNA的Olive尾矩和8-OHdG生成量明显升高,差异有统计学意义（P<0.05）。与1μg/ml乙酸铅单独染毒组比较,1μg/ml乙酸铅+10μg/ml纳米二氧化钛联合染毒组L02细胞DNA的Olive尾矩和8-OHdG生成量明显升高,差异有统计学意义（P<0.05）。与阴性对照组和1μg/ml乙酸铅单独染毒组比较,1μg/ml乙酸铅+0.001～1μg/ml纳米二氧化钛组L02细胞OGG1的表达水平均明显升高,差异有统计学意义（P<0.05）。随着乙酸铅的添加以及纳米二氧化钛染毒浓度的升高,L02细胞DNA的Olive尾矩和8-OhdG生成量均呈上升趋势,OGG1的表达水平呈下降趋势。乙酸铅和纳米二氧化钛对DNA损伤修复蛋白OGG1的表达存在协同作用,但对Olive尾矩水平和8-OHdG生成量不存在交互作用。结论低浓度乙酸铅和纳米二氧化钛联合暴露可使L02细胞DNA损伤增加,OGG1应激性增高以修复DNA损伤,但持续增加的DNA损伤会使OGG1水平下降。     

双酚A及纳米二氧化钛对人胚肝L-02细胞内活性氧含量及DNA损伤的联合作用

[目的]观察双酚A（BPA）、纳米二氧化钛（nano-TiO2）单独及联合作用对人胚肝L-02细胞内活性氧（reactive oxygen species，ROS）含量及DNA损伤的影响。[方法]生长良好的L-02细胞，分别单独加入0．1、1、10μmol／L的BPA，1、5、10mg／L的nano-TiO2，以及上述各浓度的BPA和nano-TiO2混合染毒24h；采用流式细胞仪检测各组L-02细胞内ROS含量，采用彗星试验观察各组DNA断裂损伤程度。[结果]10μmol／L BPA单独染毒组，1mg／L nano-TiO2与1、10μmol／L BPA，以及5、10mg／L的nano-TiO2分别与0．1、1、10μmol／L BPA联合作用于L-02细胞后，均可引起ROS含量升高，DNA断裂损伤加重，与阴性对照组比较差异有统计学意义（P〈0．001）；而nano-TiO2单独染毒组对于L-02细胞ROS的升高、DNA损伤作用与阴性对照组比较差异均无统计学意义（P〉0．05）。析因分析结果显示两种受试物混合染毒存在协同作用。[结论]BPA和nano-TiO2联合作用可增加各自对L-02细胞内ROS水平和DNA损伤断裂水平的影响，对细胞的损伤作用增大。     

外照射联合腔内后装治疗T1、T2期鼻咽癌的疗效观察

目的探讨鼻咽癌外照射后期联合高剂量率腔内后装治疗的效果及并发症.方法有计划地对首程T1、T2期鼻咽癌患者52例,分为单纯外照射组(26例)和外照射联合高剂率腔内后装推量组(综合放疗组26例),其中综合放疗组在鼻咽癌外照射至DT40Gy、50Gy、60Gy时行腔内后装治疗一次.结果综合放疗组与单纯放疗组的三年肿瘤局部控制率分别是100%与73.08%,两组有显著性差异(P＜0.01);3年生存率是92.31%和84.61%,无明显差异(P＜0.05).结论 T1、T2期鼻咽癌外照射后期联合高剂量率腔内后装治疗能提高肿瘤局部控制率,减少外照射的剂量及降低其并发症的产生.     

Stress-Induced Transcriptional Changes and DNA Damage Associated with Bis(2-ethylhexyl) Adipate Exposure in Zebrafish (<Emphasis Type="Italic">Danio rerio</Emphasis>) Larvae

The present study evaluates potential toxic effects of bis(2-ethylhexyl) adipate (DEHA) plasticizer to larval (72 h post fertilization) zebrafish (Danio rerio) by analyzing changes in expression levels of stress-related genes (p53, rad51 and xrcc5) and assessing possible DNA damage of DEHA in larvae. The lethal concentration for 50% mortality (LC₅₀) in larval zebrafish exposed for 96 h to 0–200 mg L^?1 DEHA was 89.9?±?8.03 mg L^?1. A concentration-dependent increase in DNA strand breaks was detected in cells from larvae exposed for 96 h to DEHA. There were some significant differences in induction of stress-related genes in larvae exposed to DEHA relative to control.