Oakes Ken D, Hewitt L Mark, McMaster Mark E, Wood Craig, Munkittrick Kelly R, Van Der Kraak Glen J
Department of Zoology, University of Guelph, Guelph, Ontario, Canada.
J Toxicol Environ Health A. 2005 Feb 27;68(4):267-86. doi: 10.1080/15287390590895621.
This study investigates the relationship between oxidative stress and reproductive dysfunction in wild white sucker (Catostomus commersoni) with short-term exposures to pulp-mill effluent. Hepatic oxidative damage, as quantified using 2-thiobarbituric acid-reactive substances (TBARS), was often increased with effluent exposure within 4-8 d, but responses varied by species, sex, and effluent. Fatty acyl-coenzyme A (CoA) oxidase (FAO) and ethoxyresorufin O-deethylase (EROD) activities were also significantly induced between 4 and 8 d of exposure. There were marked species differences in oxidative stress, as TBARS, FAO, and EROD responses in white sucker differed dramatically from those of longnose sucker (Catostomus catostomus) exposed under identical conditions. Exposure for 8 d to pulp-mill effluent delayed ovulation in white sucker, and these delays were independent of changes in circulating testosterone and 17alpha,20beta-dihydroxy-4-pregnen-3-one titers. Evaluations of the effects of pulp mill effluent on in vivo plasma steroid levels and in vitro steroidogenic capacities were compromised due to caging stress. In vivo preexposure to pulp-mill effluent did not reduce in vitro ovarian follicle steroidogenic capacities when exposed to additional reactive oxygen species (ROS) generators. Endocrine and oxidative stress parameters may be interrelated, as the in vivo administration of ferric nitrilotriacetate (Fe(3+)NTA) significantly reduced circulating sex steroids. Administration of a superactive GnRH analog containing a dopamine inhibitor significantly increased TBARS within 24 h, indicating endocrine status is capable of modifying oxidative stress responses. This study provides new knowledge regarding the onset of oxidative stress and changes in reproductive endpoints in fish following pulp-mill effluent exposure.
本研究调查了野生白亚口鱼（Catostomus commersoni）短期暴露于纸浆厂废水后氧化应激与生殖功能障碍之间的关系。使用2-硫代巴比妥酸反应性物质（TBARS）定量的肝脏氧化损伤，在暴露于废水4-8天内通常会增加，但反应因物种、性别和废水而异。脂肪酰辅酶A（CoA）氧化酶（FAO）和乙氧异吩恶唑酮O-脱乙基酶（EROD）活性在暴露4至8天之间也有显著诱导。氧化应激存在明显的物种差异，因为白亚口鱼的TBARS、FAO和EROD反应与在相同条件下暴露的长鼻亚口鱼（Catostomus catostomus）有显著差异。暴露于纸浆厂废水8天会延迟白亚口鱼的排卵，这些延迟与循环睾酮和17α,20β-二羟基-4-孕烯-3-酮水平的变化无关。由于饲养应激，对纸浆厂废水对体内血浆类固醇水平和体外类固醇生成能力影响的评估受到影响。当暴露于额外的活性氧（ROS）生成剂时，体内预先暴露于纸浆厂废水不会降低体外卵巢卵泡类固醇生成能力。内分泌和氧化应激参数可能相互关联，因为体内施用次氮基三乙酸铁（Fe(3+)NTA）会显著降低循环性类固醇。施用含有多巴胺抑制剂的超活性GnRH类似物在24小时内显著增加了TBARS，表明内分泌状态能够改变氧化应激反应。本研究提供了关于鱼类暴露于纸浆厂废水后氧化应激的发生和生殖终点变化的新知识。
