低剂量三丁基锡和镉联合暴露对鲤鱼甲状腺轴及抗氧化指标的影响

发布时间：2018-05-20 20:38

本文选题：镉 + 三丁基锡　；参考：《华中农业大学》2017年硕士论文

【摘要】：镉(Cd)和三丁基锡(TBT)是环境中常见的内分泌污染物,能够影响水生生物的生长发育及内分泌代谢,对生物体产生毒性作用。有关Cd和TBT单一暴露对鱼类毒性影响的研究较多,但关于Cd和TBT联合暴露对鱼类毒性效应的研究很少。事实上,联合毒性研究更有助于客观地评价污染物在环境中的真实毒性。本研究以淡水经济鱼类鲤鱼(Cyprinus carpio)为研究对象,以氯化镉(CdCl2)和三丁基氯化锡(TBTCl)作为目标毒物,设定对照组、镉单独暴露组、三丁基锡单独暴露组及镉和三丁基锡的联合暴露组,进行不同时间(1 d、2 d、4 d、8 d、16 d、32 d、48d)的毒性暴露实验,通过检测一系列的生理生化指标(形态学指标、抗氧化指标、血液指标等)及甲状腺轴(HPT)相关基因表达,研究低剂量三丁基锡和镉单独暴露及联合暴露对鲤鱼甲状腺轴和抗氧化系统的毒性影响。本研究的实验结果如下:1.形态学指标测量结果显示:在暴露48d时,TBT使鱼的肥满度(CF)显著下降且肝体指数(HSI)显著升高;而Cd对CF和HSI无影响;联合暴露组的HSI也出现显著升高。就形态学指标而言,Cd和TBT的联合毒性作用弱于TBT单独暴露。2.生理生化指标结果显示:在暴露初期,Cd和TBT的单独暴露及联合暴露均对鲤鱼肝脏中抗氧化指标(SOD、CAT、MDA、GR和GSH)及血液指标(葡萄糖和总蛋白)产生了不同程度的诱导和抑制效应,但随着暴露时间的延长,相对于Cd和TBT的单独暴露,Cd和TBT联合暴露对鲤鱼大部分抗氧化指标的诱导和抑制效应减弱,但对MDA及血液中葡萄糖和总蛋白含量影响增强。3.甲状腺组织切片镜检结果显示:所有暴露组鲤鱼在暴露48d后均出现甲状腺滤泡上皮细胞高度增加,滤泡上皮细胞增生,滤泡变形等现象。其中Cd组和TBT组还出现了滤泡胶质缺失现象。而二者联合暴露对甲状腺的组织损伤反而相对较小。4.血浆中激素含量测量结果显示:Cd和TBT的单独暴露及联合暴露均对血浆中T3、T4含量造成影响,其中联合暴露组的影响更为明显,在暴露2 d时就会导致血浆中T3、T4的含量显著降低。整体来看,Cd和TBT的联合暴露对鲤鱼血浆中甲状腺激素产生较大的干扰效应。5.甲状腺轴相关基因结果显示:HPT轴基因表达水平在Cd和TBT的单独暴露及联合暴露下均受到一定程度的影响,基因的表达水平在不同的暴露组以及不同的暴露时间不尽相同。Cd、TBT及二者的联合暴露可通过影响HPT轴相关基因的表达对HPT轴产生干扰作用。
[Abstract]:Cadmium (Cd) and three butyltin (TBT) are common endocrine pollutants in the environment, which can affect the growth, development and endocrine metabolism of aquatic organisms and produce toxic effects on organisms. There are many studies on the effects of single exposure to Cd and TBT on fish toxicity, but there are few studies on the toxic effects of Cd and TBT exposure on fish. The study of combined toxicity is more conducive to the objective evaluation of the real toxicity of pollutants in the environment. In this study, the freshwater economic fish carp (Cyprinus carpio) was studied with cadmium chloride (CdCl2) and three butyl chloride (TBTCl) as the target poison. The control group, the single cadmium exposure group, the three butyltin exposure group and the cadmium and three butyl tin were set. The toxic exposure tests of the combined exposure group (1 D, 2 D, 4 D, 8 D, 16 D, 32 D, 48D) were carried out to study a series of physiological and biochemical indexes (morphological, antioxidant, blood, etc.) and thyroid axis (HPT) related genes, and the low dose of three butyltin and cadmium were exposed and exposed to common carp thyroid gland. The toxic effects of axis and antioxidant system. The results of this study were as follows: 1. the results of morphological index measurements showed that when exposed to 48D, TBT significantly decreased the fullness of the fish (CF) and significantly increased the liver body index (HSI), while Cd had no effect on CF and HSI, and the HSI in the combined exposure group was also significantly elevated. As for morphological indicators, Cd and TBT were associated with the morphological index. The results of physiological and biochemical indicators that were less than TBT exposure to.2. showed that both exposure to Cd and TBT in the early exposure and combined exposure to combined exposure and exposure to the liver of carp (SOD, CAT, MDA, GR and GSH) and blood indexes (glucose and total protein) were induced and inhibited in different degrees, but with the prolongation of exposure time, Compared with the exposure of Cd and TBT, the induction and inhibition effect of combined exposure to Cd and TBT on most of the antioxidant indices of carp decreased, but the effect of MDA and blood glucose and total protein content in.3. thyroid tissue section microscopy revealed that all exposed group carp appeared thyroid follicle epithelial cell height after exposed to 48D. Increase, follicular epithelial cell proliferation, follicular deformation and so on. In group Cd and TBT, there was a phenomenon of follicular glia loss. The results of hormone content measurements in the two groups of combined exposure to thyroid tissue damage in the relatively small.4. plasma showed that both Cd and TBT exposure and combination exposure were affected by the content of T3 and T4 in plasma, The effects of the combined exposure group were more obvious, and the concentrations of T3 and T4 in the plasma were significantly reduced when exposed to 2 D. Overall, the combined exposure of Cd and TBT to the thyroid hormones in the plasma of carp.5. thyroid axis related gene results showed that the HPT axis gene expression level was separately exposed and linked to Cd and TBT. The expression level of gene expression is not the same as.Cd in different exposure groups and different exposure time. The combined exposure of TBT and two can interfere with the HPT axis by influencing the expression of HPT axis related genes.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X503.225;S917.4

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