百草枯对小鼠肝脏的损伤研究

为了解百草枯对哺乳动物肝脏损伤的特性,以便有效寻找针对性治疗药物,试验建立了小鼠模型,分别向昆明白雄鼠腹腔注射30、60、90 mg/kg不同浓度的百草枯,各处理分别于6、12 h以及1、3、7 d后测定血清中的谷丙转氨酶(ALT)和谷草转氨酶(AST)活性,对百草枯染毒的各浓度处理小鼠肝脏进行苏木精-伊红染色,观察其病理学变化,然后选取中剂量60 mg/kg处理的不同时间组(6、12 h以及1、3、7d),通过Realtime PCR检测IL-1β、IL-6、TNF-α、Caspase-3、Caspase-8基因表达变化。结果表明,百草枯30、60、90 mg/kg不同浓度处理的血清ALT、AST活性在不同处理时间上均高于对照,在7 d后各血清ALT、AST活性均又呈现下降趋势。染色结果发现在处理3 d后的30 mg/kg的小鼠肝脏病理学变化不明显,90 mg/kg处理出现较为明显的炎症变化。Realtime PCR结果显示,60 mg/kg不同时间处理的IL-1β、IL-6、TNF-α、Caspase-3、Caspase-8基因表达从6 h后开始呈现上升趋势,在3 d后基因表达略有下降。不同浓度的百草枯对小鼠肝脏均有损伤,高剂量百草枯对肝脏损伤较严重,且对血清中免疫因子和相关基因的表达有显著影响。     

Effects of gender and temperature on oxidative stress enzymes in Nile tilapia Oreochromis niloticus exposed to paraquat

Many classes of environmental pollutants can enhance the intracellular formation of reactive oxygen species, which can conduce to the damage of macromolecules and changes in oxidant defences levels in fish. In the present study it was analysed the hepatic levels of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione S-transferase (GST) in males and females of Nile tilapia Oreochromis niloticus exposed to paraquat (PQ), at 17 and 27 °C. Tilapia were exposed to a sublethal concentration of PQ (0.5 mg L⁻¹) during 45 days. Condition factor and hepatosomatic index of males and females exposed to PQ were significantly higher when compared with the control group, except in females at 17 °C. SOD and GST activities were higher in males and females exposed to PQ than in the control group at 17 and 27 °C. The levels of both enzyme activities revealed that they are sex-dependent with males exposed to PQ showing higher SOD activity (5.05 ± 0.13 and 4.84 ± 0.23 U/g protein, respectively at 17 and 27 °C) than females (4.21 ± 0.07 and 3.87 ± 0.27 U/g protein, respectively at the same temperature). Similar results were observed in GST activity. A GR activity significantly higher (9.09 ± 0.44 and 7.97 ± 1.08 U/g protein at 17 and 27 °C, respectively) was observed in PQ-exposed females, but not in exposed males. Fish exposed to PQ showed higher values of SOD and GST activities than the control group at both temperatures. These results are gender-dependent, while GR activity was higher only in PQ-exposed females. No significant differences were found for SOD, GST and GR activities between fish exposed to 17 and 27 °C, although males and females showed higher values at 17 °C. In short, this work advanced new knowledge on influence of gender in same biochemical parameters in tilapia exposed to PQ and demonstrated that their effects could be observed at different temperatures.     

Effect of methylene blue on T-lymphocyte subsets and oxidative stress in rat thymus with paraquat poisoning

AIM: To illustrate the effect of methylene blue(MB) on T-lymphocyte subsets and oxidative stress of the thymus in rats with paraquat(PQ) poisoning.METHODS: Male SD rats(n=40) were randomly assigned to 4 groups: normal group, control group, low-dose(2 mg·kg^-1·d^-1) MB group and high-dose(4 mg·kg^-1·d^-1) MB group. After 72 h, the pathological morphological changes of the thymus were observed under microscope with HE staining. The SOD activity and MDA content were measured by colorimetry method. The expression of Bcl-2, Bax, CD4 and CD8 was determined by immunohistochemical method.RESULTS: In MB group, the thymus tissue showed good corticomedullary demarcation. MDA content decreased and SOD activity increased, indicating that the ability of antioxidation enhanced. Bcl-2 and Bax expression was down-regulated, Bcl-2/Bax ratio increased, and CD4 positive cells increased.CONCLUSION: MB protects against oxidative damage induced by PQ, and regulates the distribution of T-lymphocyte subsets in the cortex and medulla, thus relieving the persistent body damage.     

不同大豆品种对触杀型除草剂耐受性研究

采用不同浓度除草剂处理大豆叶片,对4个大豆品种的草铵膦和百草枯耐受性进行研究。结果表明,不同品种对两种除草剂的耐受性存在明显差异,以中豆32对百草枯耐受的最高浓度为0.24mg/L;中黄10号次之,为0.18mg/L;东农50和小粒豆最低为0.12mg/L。中豆32对草铵膦耐受的最高浓度为6mg/L;吉林小粒豆1号次之,为4mg/L;中黄10号和东农50的耐受浓度均为3mg/L。     

百草枯污染土壤的微生物生态效应

研究了除草剂百草枯在3种不同浓度下对土壤微生物的种群数量及其部分活性的影响。结果表明,施用百草枯对土壤微生物有明显的影响。0.05~5mg/kg的百草枯在施药后30d内,真菌种群严重被抑制;硝化细菌种群和纤维素分解菌种群均呈刺激效应;低浓度的百草枯刺激土壤细菌和放线菌种群的生长,而高浓度的百草枯则抑制其生长。结果同时表明,百草枯对土壤硝化作用和纤维素分解强度的影响均表现为刺激效应。随着加药时间的延长,这种刺激或抑制作用又逐渐恢复或接近正常水平。     

Effect of taurine on kidney injury induced by paraquat poisoning in rats

AIM:To study the effects of taurine at different doses on renal oxidative stress and inflammation induced by paraquat in rats.METHODS:Male SD rats (n=48) were randomly divided into 4 groups:negative control group,paraquat group,paraquat+low-dose taurine group,and paraquat+high-dose taurine group.The serum levels of creatinine and urea nitrogen were detected by a biochemical analyzer.The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured by colorimetry.The plasma concentrations of IL-6 and intercellular adhesion molecule (ICAM)-1 were detected by ELISA.Renal reactive oxygen species (ROS) was checked by fluorescence probe dihydroethidium (DHE).The protein levels of renal p-P38 MAPK,p-ERK1/2 and p-JNK were determined by Western blot.The mRNA expression of TNF-α,IL-6 and TGF-β1 was detected by real-time PCR.RESULTS:Serum creatinine and urea nitrogen increased after paraquat poisoning,and decreased after feeding with taurine in poisoned rats,with better result in high-dose taurine group.Taurine reduced the oxidative stress and inflammation in the renal tissue,and also reduced the protein levels of p-JNK,p-ERK1/2 and p-P38 in the kidney of paraquat-poisoned rats.CONCLUSION:Taurine attenuates renal injury induced by paraquat poisoning in rats.The mechanism may be related to reducing renal MAPK activity,oxidative stress and inflammatory response.     

2种除草剂对马铃薯地土壤微生物群落的影响

[目的]探究2种除草剂对马铃薯土壤微生物生态多样性变化的影响。[方法]结合田间取样调查及室内试验培养方法研究了百草枯和草甘膦2种除草剂对马铃薯土壤微生物(细菌、真菌和放线菌)种群数量、微生物群落的影响。[结果]2种除草剂对马铃薯地0～10 cm和10～15 cm深度的土壤细菌和真菌数量影响不大;2种除草剂处理40 d时,放线菌增长被抑制,其数量呈下降趋势,但60 d后放线菌数量逐渐上升呈恢复趋势。[结论]为进一步研究百草枯和草甘膦对农业生态系统的影响提供了理论依据。     

Nonthiol ACE inhibitors, enalapril and lisinopril are unable to protect mitochondrial toxicity due to paraquat

Angiotensin-converting enzyme inhibitors (ACEi) were shown to ameliorate endothelial dysfunction in various human diseases and some of these inhibitors have been reported to enhance antioxidant defenses. The objective of the present study was to shown the abilities of enalapril and lisinopril as two nonthiol ACEi on mitochondrial toxicity due to paraquat. In this study, mitochondrial isolation from rat liver was divided into six groups. Group 1 was considered as control, group 2 received paraquat (5 mM), group 3 received enalapril (0.25 mM), group 4 received lisinopril (0.01 mM), group 5 received paraquat (5 mM) + enalapril (0.25 mM), and group 6 received paraquat(5 mM) + lisinopril (0.01 mM). Viability, lipid peroxidation, catalase activity, GSH (reduced glutathione) and GSSG (oxidized glutathione) concentrations were also determined. Simultaneous treatment of mitochondria with enalapril (0.25 mM) + paraquat (5 mM) and lisinopril (0.0.01 mM) + paraquat (5 mM) did not significantly ameliorate the mitochondrial toxicity induced by paraquat (5 mM) alone (p > 0.05). However, the nonthiol ACEi, enalapril showed to partially improve target of lipid peroxidation due to paraquat. In conclusion, nonthiol ACEi treatment did not improve the increased oxidative stress and the decreased antioxidant mechanisms.     

百草枯中毒对大鼠的肺损伤作用研究

[目的]观察一次性灌胃染毒百草枯对大鼠肺组织的损伤情况。[方法]将20只大鼠随机分为对照组和百草枯组,百草枯组一次性染毒百草枯50 mg/kg体重,对照组用生理盐水代替,观察大鼠一般情况变化,染毒前后对大鼠进行跑步机训练,比较2组大鼠灌胃前以及灌胃后第5、10、15天跑步机上掉落次数。于染毒后第15天麻醉处死大鼠,收集肺组织,碱水解法测定肺组织羟脯氨酸含量,HE染色观察大鼠肺组织病理学变化。[结果]百草枯组大鼠灌胃后一般状况差,百草枯组平均进食量较对照组显著降低。灌胃前大鼠跑步时掉落次数2组间并无显著差异,但灌胃后百草枯组掉落次数较对照组增加。百草枯组大鼠肺组织羟脯氨酸含量极显著较对照组高,病理切片显示染毒组肺组织肺泡腔塌陷,肺泡间隔明显增宽,间质呈纤维性增厚。[结论]百草枯一次性染毒导致大鼠肺组织纤维化。     

Expression of genes related to Parkinson’s disease after paraquat treatment in Drosophila melanogaster

This study was designed to determine the minimum effective concentration of paraquat that modulated the expression of PKD-related genes in Drosophila. We first studied the viability of Drosophila and then tested the expression of the PKD-related genes—Parkin, UCH, and tau—in various concentrations of paraquat in the water sucked by Drosophila. The lowest effective concentration of paraquat was approximately 20 μM and the gene expression was induced at paraquat doses between 20 mM and 20 μM. Parkin and tau expression was inhibited, while that of UCH was significantly increased.Next, we examined the expression of the Parkin and UCH genes in the neurons of SOD-reduced mutants under oxidative stress conditions and found that Parkin was up regulated, while UCH was down regulated. We also found that the expression of Parkin was regulated by JNK. This study revealed that paraquat affects the expression of PKD-related genes via oxidative stress.In conclusion, our results showed that paraquat in the water sucked by Drosophila altered the gene expression at a minimum concentration of 20 μM, and that it not only promoted but also inhibited PKD-related gene expression via signal transduction mediated by oxidative stress. In order to confirm whether paraquat is a causal factor of PKD, more balanced and in-depth tests seem to be done looking into multiple aspects.