Oxidative stress and apoptosis of Carassius auratus lymphocytes induced by nonplanar （PCB153） and coplanar （PCB169） polychlorinated biphenyl congeners in vitro

Among all the 209 kinds of polychlorinated biphenyls (PCBs) congeners, nonplanar and coplanar PCB congeners have di erent levels of toxicity on mammal cells such as neuronal cells, but little is known about their toxicity on fish cells although PCB congeners usually have high bioaccumulation abilities in the detected fish bodies. This study showed that 2,2’,4,4’,5,5’-hexacholorbiphenyl (PCB153, nonplanar congener) and 3,3’,4,4’,5,5’-hexacholorbiphenyl (PCB169, coplanar congener) caused apoptosis on the isolated crucian carp (Carassius auratus) lymphocytes and the induced cytotoxicity was structure-dependent. According to the laser confocal microscope observations, apoptosis was clearly distinguished by condensation of nucleus, shrinkage and formation of apoptotic bodies. DNA fragmentation was detected by agarose gel electrophoresis. These typical morphological and biochemical characteristics indicate the occurrence of apoptosis on fish lymphocytes. According to the flow cytometry analysis, after the cells were exposed to 10 mol/L PCBs for 3 h, the apoptotic percentage induced by PCB153 was 23.41%, while that induced by PCB169 was even higher (31.03%). Furthermore, incubating PCBs with fish lymphocytes enhanced levels of reactive oxygen species (ROS) and malondialdehyde (MDA), clearly indicating the presence of oxidative stress and lipid peroxidation. Our data also demonstrate that the di erent cytotoxic e ects induced by coplanar and nonplanar PCBs were correlated with their structural characteristics and the coplanar congener was more cytotoxic than nonplanar congener. This study suggests that cytotoxicity mechanisms of the PCB congeners on fish lymphocytes depend on their planarity and chemical structures.     

镉暴露致黑斑蛙精巢氧化损伤与DNA损伤

在实验条件下,将健康性成熟黑斑蛙(Rana nigromaculata)暴露于0.005、0.01、0.05、0.1、0.5和1.0 mg·L-1浓度的镉溶液中30 d,采用慧星实验检测其精巢细胞DNA损伤,并测定精巢组织中活性氧自由基(ROS)的水平和脂质过氧化主要终产物丙二醛(MDA)含量,探讨镉暴露对黑斑蛙精巢组...     

Health risk assessment and oxidative stress in workers exposed to welding fumes

The aim of this study was designed to determine the influence of welding fumes on oxidative stress in humans and the role of metals. A questionnaire was designed to collect information regarding personal characteristics, including age, weight, height, and medical history; life style such as smoking status and exercise habits; and occupational history such as working history, working environment, employment duration, and use of protective equipment. Body mass index (BMI) in kg/m² was then calculated for each participant. Blood samples were also drawn to determine malondialdehyde (MDA) levels and various metals in plasma. Significantly higher plasma MDA (4.08 µg/L) was observed as compared to controls (1.61 µg/L). Blood metal analysis also showed elevated level of metals in welders for cadmium, chromium, lead,and nickel. Data indicated that workers occupationally exposed to welding fumes for prolong periods possessed higher metal levels associated with increased oxidative stress as evidenced by elevated MDA levels.     

砷在不同物候期香蒲中的分布及其生理影响

为研究砷(As)在挺水植物中的富集和植物的逆境适应特征,以香蒲(Typha angustifolius L.)为例,通过水培模拟实验,研究As(浓度为0、0.5、2.0、5.0、10.0 mg/L)胁迫下不同物候期(生长期、花果期、枯黄期)香蒲叶组织和亚细胞水平As的分布特征及对活性氧代谢的生理影响。结果表明:香蒲叶组织As含量随As胁迫浓度的增加呈现逐渐升高的趋势;随着香蒲的生长(生长期、花果期、枯黄期),叶组织中As含量呈现先升高后下降的趋势,As含量在生长期最高,表明生长期的香蒲对As的富集积累能力最强。在As胁迫下,随着香蒲的生长,叶细胞壁和细胞液中As的分布比例之和为63.5%~84.5%,表明细胞壁和细胞液组分是香蒲储存As的主要部位。As对不同物候期香蒲叶中过氧化物酶(POD)活性的影响与As浓度呈正相关,对过氧化氢酶(CAT)活性产生低促高抑的作用,在不同物候期,POD与CAT存在互补关系,表明香蒲通过限制As细胞壁的固持和细胞液的区隔化来降低As的毒害;超氧化物歧化酶(SOD)和丙二醛(MDA)含量随香蒲生长和As浓度增加均显著增加,表明抗氧化酶相互协作是香蒲应对As胁迫的重要策略。