In vitro exposure of human spermatozoa to bisphenol A induces pro-oxidative/apoptotic mitochondrial dysfunction

As bisphenol A (BPA) exerts oxidative/pro-apoptotic effects in several cell types, we explored whether the in vitro exposure to BPA could affect human sperm integrity through the induction of pro-oxidative/apoptotic mitochondrial dysfunction. The exposure of motile sperm suspensions to scalar BPA concentrations for 4 h produced a decrease in the mitochondrial membrane potential, starting from 300 μM. It was associated with an increased mitochondrial generation of superoxide anion, caspase-9 and caspase-3 activation and motility decrement. Vitality decline was observed at BPA ≥ 400 μM. Twenty hours exposure to 300 μM BPA, but not to lower concentrations, produced a significant loss in sperm vitality associated with a complete sperm immobilization. Finally, 300 μM BPA also produced a significant DNA oxidative damage, as revealed by the formation of oxidized base adduct 8-hydroxy-2′-deoxyguanosine. In conclusion, BPA affected human sperm integrity by inducing pro-oxidative/apoptotic mitochondrial dysfunction.     

脂肪肝患者血脂、血糖及肝功能损害的相关性研究

目的研究脂肪肝患者血脂、血糖以及肝功能损害之间的相关性。方法选择2010年9月～2011年3月在笔者所在医院超声科检查确诊的196例脂肪肝患者作为观察组,同时选择同时期门诊体检的120例健康者作为对照组,分别检测两组的血脂、血糖、肝功能指标水平,并进行统计学分析和处理。结果观察组TC、TG、LDL-C、FBG均显著高于对照组,而HDL-C显著低于对照组,观察组ALT、AST、GGT均显著高于对照组,两组比较差异有统计学意义(P<0.05)。结论脂肪肝与高血脂、高血糖以及肝功能损害有一定的关联。     

尿微量白蛋白与妊娠期高血压疾病早期肾损伤关系的研究

目的探讨尿微量白蛋白(尿mALB)与妊娠期高血压疾病患者早期肾损害的关系,评价临床诊断价值。方法采用免疫散射比浊法检测60例孕25～42周孕妇尿微量白蛋白(尿蛋白定性均为阴性),其中30例妊娠期高血压孕妇作为观察组,另30例正常孕妇为对照组。结果观察组尿微量白蛋白(26.01±7.28)mg/L,超过参考值阳性率60.00%。对照组尿微量白蛋白(8.17±2.98)mg/L,超过参考值阳性率10.00%。两组比较有统计学差异(P<0.05)。结论妊娠期高血压疾病早期肾损伤患者尿微量白蛋白明显升高,检测尿微量白蛋白可用于及早发现妊娠期高血压疾病的早期肾损伤,对及时干预,阻止病情发展有其重要的临床意义。     

视网膜光损伤：Ⅰ.中,低强度循环光下光照强度及照射时间的作用

目的:研究中、低强度的循环光照射对鼠视网膜光损伤的影响及其与时间、强度的关系。方法:25只8～10周的雌性SD鼠随机分为5组。一组作对照,另外四组置于12小时亮、12小时暗的白色氙灯循环光下照射3～28天,照射强度分别为90～115Lux(100Lux)、400～650Lux(500Lux)、800～1150Lux(1000Lux)、1400～1650Lux(1500Lux)。照射不同时间后,对视网膜行光镜、电镜检查及组织测厚。结果:除100Lux组光强度外,500Lux、1000Lux、1500Lux组的光强度均能引起鼠视网膜光损伤。视网膜光感受器细胞最早受累。光强度越高、照射时间越长,光感受器细胞的丧失越多;损伤严重者,也伴有视网膜色素上皮的损伤。结论:中、低强度的循环光所造成的鼠视网膜光损伤,其损伤程度与光照强度和照射时间有关。是光损伤防护中值得注意的环节。眼科学报1998;14:215～219。     

Ochratoxin A induces oxidative DNA damage and G1 phase arrest in human peripheral blood mononuclear cells in vitro

Ochratoxin A is one of the most abundant food-contaminating mycotoxins worldwide, and its immunosuppressive effects in human caused more and more concern in biomedical field. In the present study, the toxicity of OTA on human peripheral blood mononuclear cells (hPBMC) was explored by analyzing the involvement of oxidative pathway. It was found that OTA treatment led to the release of reactive oxygen species (ROS) and the increase of 8-hydroxydeoxyguanosine (8-OHdG), an important biomarker of oxidative DNA stress. Moreover, we found that OTA treatment induced DNA strand breaks in hPBMC as evidenced by DNA comet tails formation and increased γ-H2AX expression. In addition, OTA could induce cell cycle arrest at G1 phase by down-regulating the expression of CDK4 and cyclinD1 protein, as well as apoptosis in hPBMC in vitro. Pre-treatment of hPBMC with antioxidant, N-acetyl-L-cysteine (NAC), could reduce OTA-induced ROS release and DNA damage, thus confirming the involvement of oxidative DNA damage in the OTA genotoxicity in hPBMC. NAC pre-treatment could also significantly prevent OTA-induced down-regulation of CDK4 and cyclinD1 expression in hPBMC. All the results demonstrated the involvement of oxidative pathway in OTA mediated cytotoxicity in human immune cells, which including the ROS accumulation-oxidative DNA damage-G1 arrest and apoptosis. Our results provide new insights into the molecular mechanisms by which OTA might promote immunotoxicity.     

Effects of methylmercury exposure on neuronal differentiation of mouse and human embryonic stem cells

Sulphur mustard (SM) is a blistering agent that causes debilitating damage to the skin, eyes and respiratory system. In cases of severe exposure, immunodepletion can occur as well as death, due to secondary infections. The toxicity of SM is thought to be mediated in part by the alkylation of nucleic acids and proteins, although the exact mechanisms are not clear. In addition, although the first known use of SM was in military conflict nearly 100 years ago, there are still no effective treatments or preventative measures. In order to develop treatments it is necessary to have a detailed understanding of the cellular biochemical changes induced by SM as well as information on the mechanisms that cells employ to protect against SM toxicity. We have previously demonstrated that the homologous recombination (HR) DNA repair pathway promotes cell survival after SM. This study investigated the role of other DNA repair pathways in the cellular response to SM, specifically base excision repair (BER), nucleotide excision repair (NER) and non-homologous end joining (NHEJ) as well as studying the activation and regulation of DNA damage signalling pathways. Our data confirmed that HR is the major repair pathway protecting against acute SM toxicity, with NER and NHEJ also contributing to cell survival. In addition, this study demonstrated the dose- and time-dependent activation of DNA damage signalling pathways after SM in human TK6 lymphoblastoid cells, in particular the phosphorylation of CHK1, CHK2 and p53. These phosphorylation events were orchestrated by a combination of the ATM and ATR protein kinases.     

Melamine induced cognitive impairment associated with oxidative damage in rat's hippocampus

Previous studies reported that melamine could affect hippocampal function and cause spatial cognition impairment. Moreover, some evidences implied that there might be an oxidative damage pathway linking melamine to the function of hippocampus in vitro, but there was a paucity of data about this adverse effect in vivo. The aim of this study was to investigate the toxicology of melamine induced by oxidative damage in hippocampus in vivo. Male Wistar rats were randomly divided into two groups: control group (n = 8) and melamine group (n = 8). The animals were treated with melamine at a dose of 300 mg/kg/day in 1% carboxymethylcellulose (CMC) solution as a suspension by oral administration, while rats received the same dose of solution of 1% CMC in control group. Melamine was given once a day and for 28 consecutive days. The MWM experiment and histopathological examination were performed. MWM results showed that there were significant deficits of spatial learning and memory in melamine group. The levels of superoxide anion radical, hydroxyl free radical and malonaldehyde (MDA) were significantly increased by melamine, which also reduced the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The analysis of hippocampal energy metabolism showed that melamine caused significant decrease in the content of adenosine-triphosphate (ATP), implying the reduction of energy synthesis in hippocampal neurocytes. The results suggest that the selective neurotoxicity of melamine in hippocampus may be in part associated with oxidative damage.     

1,2-二氯乙烷对淋巴细胞DNA损伤的γH2AX识别抗体流式细胞术检测

目的 探讨γH2AX识别抗体流式细胞术(FCM)检测1,2-二氯乙烷(1,2-DCE)接触工人外周血淋巴细胞DNA损伤的可行性及1,2-DCE对健康人外周血淋巴细胞DNA的损伤.方法 提取某制鞋厂接触1,2-DCE的工人21例(接触组)和该厂未接触1,2-DCE的工人27例(内对照组)及某海岛非职业接触有害因素居民28例(外对照组)的外周血淋巴细胞,采用FCM法检测淋巴细胞DNA损伤情况;用不同浓度(5、10、20和30 μmol/L)的1,2-DCE分别对健康人外周血淋巴细胞体外染毒0.5、1.0 h,采用FCM法检测淋巴细胞DNA损伤情况.结果 接触组工人DNA损伤率(4.05%±2.55%)明显高于内对照组工人(1.97%±1.40%)和外对照组人群(0.23%±0.13%),内对照组明显高于外对照组,差异均有统计学意义(P＜0.01或P＜0.05);接触组工人外周血淋巴细胞的几何平均荧光强度(3.33±3.01)与内对照组(2.07±0.58)比较,差异有统计学意义(P＜0.05).接触组不同工龄工人DNA损伤率和外周血淋巴细胞的几何平均荧光强度比较,差异均无统计学意义(P＞0.05).体外染毒0.5 h时,20、30μmol/L染毒组外周血淋巴细胞的几何平均荧光强度与阴性对照组比较,差异有统计学意义(P＜0.01).体外染毒1.0 h时,20、30μmol/L染毒组的DNA损伤率与阴性对照组比较,差异有统计学意义(P＜0.05,P＜0.01),10、20、30 μmol/L染毒组外周血淋巴细胞的几何平均荧光强度与阴性对照组比较,差异均有统计学意义(P＜0.05,P＜0.01).结论 1,2-DCE具有遗传损伤作用,FCM法是一种检测外周血淋巴细胞DNA损伤的有效方法.

Abstract：

Objective To study DNA damage of human peripheral blood lymphocytes exposed to 1,2dichloroethane (1,2-DCE) with flow cytometry (FCM) assay. Methods The lymphocytes were obtained from 21 workers who are occupationally exposed to 1, 2-DCE (exposed group ) and 27 workers who were not exposed to 1,2-DCE in the same factory (inner control ) and 28 island residents who had never been occupationally exposed to adverse factors (external control ). FCM assay was adopted to detect DNA damage of the lymphocvtes of each group. Lymphocytes of the health people were incubated with 1 ,2 - DCE at different doses, and FCM assay was used to detect DNA damage. Results DNA damage rate (%) of the exposed group of exposed workers (4.05%±2.55%) was significantly higher than the inner control group of workers ( 1.97%± 1.40% ) and external control groups of island residents (0.23%±0.13%), and the DNA damage of inner control was higher than the external control, all the differences were statistically significant (P＜0.01 or P＜0.05 ).The geometric mean fluorescence intensity of the workers in the exposed group (3.33±3.01) was significantly higher than the (2.07±0.58) only (P＜0.05). There was no significant difference in the DNA damage rate as well as the geometric mean fluorescence intensity among the exposed group of workers with different years of working period (P＞0.05). In vitro, the fluorescence intensity at the dose of 20,30 μmol/L for 0.5 h exposure showed statistical significance compared with the negative control group (P＜0.01). The DNA damage rate at the dose of 20, 30μmol/L for 1.0 h exposure was statistically significant compared with the negative control group (P＜0.05,P＜0.01 ); The fluorescence intensity at the dose of 10,20,30 μmol/L for 1.0 h exposure was statistically significant compared with the negative control group(P＜0.05,P＜0.01 ). Conclusion 1 ,2-DEC can cause DNA damage. And γH2AX FCM assay can be a sensitive, objective and effective method of detecting DNA damage of peripheral blood lymphocytes.     

姜黄素对长波紫外线所致DNA损伤的拮抗作用

目的　观察长波紫外线引起人表皮样癌细胞 DNA链断裂损伤的情况 ,以及姜黄素对这种损伤的拮抗作用。方法　用长波紫外线照射细胞 ,用单细胞凝胶电泳法检测 DNA损伤。结果　长波紫外线剂量依赖性地诱发表皮细胞的 DNA链断裂损伤 ,损伤的高峰出现在照射后 1h。而姜黄素可以拮抗长波紫外线引起的DNA链断裂 ,表现为彗星细胞百分比的降低和彗星尾巴长度的缩短 ,并有量效关系。结论　姜黄素可以预防长波紫外线照射引起的皮肤细胞 DNA链断裂损伤。     

香烟烟雾溶液作用下大鼠淋巴细胞的氧化应激反应

目的　以细胞内活性氧自由基 (ROS)水平、DNA损伤、脂质过氧化物 (LPO)水平以及超氧化物歧化酶 (SOD)活力为指标 ,研究细胞在香烟烟雾溶液作用下产生的氧化应激反应。方法　以PBS作吸收液 ,用大包氏管收集香烟主流烟雾 ,将香烟烟雾溶液 (CSS)分别以 0、1× 10 - 3、2× 10 - 3、4× 10 - 3、8× 10 - 3、12× 10 - 3、16× 10 - 3支 ml的浓度作用于大鼠淋巴细胞。用 2′ ,7′ 二乙酰二氯荧光素 (DCFH DA)测定细胞内ROS水平 ,用彗星试验检测细胞DNA损伤 ,同时检测细胞内SOD活力和LPO水平。结果　 2× 10 - 3支 ml以上剂量组二氯荧光素 (DCF)荧光强度、彗星尾长以及LPO水平均显著高于对照组 ,且随剂量增加而增加。 16× 10 - 3支 ml组SOD活力显著低于对照组。与对照组相比 ,1× 10 - 3支 ml组LPO水平显著降低、SOD活力则显著增高。结论　CSS达到一定剂量时使细胞内ROS水平增高 ,引起细胞DNA损伤和脂质过氧化 ,高剂量时SOD活力降低 ,而低剂量时能够诱导SOD活力